Merging upstream version 0.1.30.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

39 files changed, 2228 insertions, 416 deletions

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 565d0d9..b3d32b2 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -143,17 +143,26 @@ pages:
   - main
 
 variables:
-  SALSA_CI_DISABLE_WRAP_AND_SORT: 0
-  SALSA_CI_WRAP_AND_SORT_ARGS: '-abkt'
+  SALSA_CI_DISABLE_WRAP_AND_SORT: 1
   SALSA_CI_AUTOPKGTEST_ALLOWED_EXIT_STATUS: 0
   SALSA_CI_DISABLE_APTLY: 0
 
+debputy-reformat:
+  stage: ci-test
+  image: debian:sid-slim
+  script:
+    - apt-get update -qq && apt-get -qq build-dep --no-install-recommends --yes .
+    - ./debputy.sh reformat --linter-exit-code --no-auto-fix
+  except:
+    variables:
+      - $CI_COMMIT_TAG != null && $SALSA_CI_ENABLE_PIPELINE_ON_TAGS !~ /^(1|yes|true)$/
+
 debputy-lint:
   stage: ci-test
   image: debian:sid-slim
   script:
-    - apt-get update -qq && apt-get -qq install --no-install-recommends --yes dh-debputy python3-pygls
-    - PERL5LIB=lib debputy lint --spellcheck
+    - apt-get update -qq && apt-get -qq build-dep --no-install-recommends --yes .
+    - PERL5LIB=lib ./debputy.sh lint --spellcheck
   except:
     variables:
       - $CI_COMMIT_TAG != null && $SALSA_CI_ENABLE_PIPELINE_ON_TAGS !~ /^(1|yes|true)$/
diff --git a/debputy.pod b/debputy.pod
index 933b6d0..0cee740 100644
--- a/debputy.pod
+++ b/debputy.pod
@@ -14,7 +14,9 @@ B<debputy> B<check-manifest> [B<--debputy-manifest=>I<path/to/debputy.manifest>]
 
 B<debputy> B<annotate-packaging-files>
 
-B<debputy> B<lint>
+B<debputy> B<lint> [--auto-fix]
+
+B<debputy> B<reformat> [--no-auto-fix]
 
 B<debputy> B<lsp> B<editor-config> B<NAME>
 
@@ -117,6 +119,60 @@ The B<--no-act> is an alias of B<--no-apply-changes> to match the name that B<de
 
 =back
 
+=item reformat
+
+I<< Note: This subcommand needs optional dependencies to work from B<Recommends> or B<Suggests> >>
+
+Apply the formatting style on the packaging files.
+
+This is the same style that B<debputy lsp server> would have applied if requested to reformat the files.
+
+The B<debputy> tool reacts to having a B<X-Style> field in F<debian/control> from where you can pick
+a named style. The recommended style is B<black>, which is named such to match the B<black> code formatter
+for B<Python> (which imposes a style that evolves over time).
+
+For packages that does not have the B<X-Style> field, B<debputy> will result to looking up the maintainer
+(and possibly co-maintainers) for known style preferences in its built-in configuration. If B<debputy>
+can derive a style that all parties would agree too (or the team style for packaging teams), then that
+style will be used.
+
+At the time of introduction, the B<black> style is similar to that of B<wrap-and-sort -astkb>, since
+that was one of the most common style according to L<https://bugs.debian.org/895570>, But the style is
+expected to evolve over time and the two styles may diverge over time.
+
+The command accepts the following options:
+
+=over 4
+
+=item B<--style=black>
+
+Override the package style and use the B<black> style. Any auto-detection or B<X-Style> setting will
+be ignored.
+
+=item B<--auto-fix>, B<--no-auto-fix>
+
+Decide whether any changes should be fixed automatically.
+
+Either way, a difference (B<diff -u>) is displayed to stdout if any changes were detected.
+
+=item B<--linter-exit-code>, B<--no-linter-exit-code>
+
+There is a convention among linter tools to return a non-zero exit code for "issues".  The
+B<--linter-exit-code> will enforce this behaviour while the B<--no-linter-exit-code> will disable
+it.
+
+The B<debputy> program will use exit code B<2> for "issues" as a "linter exit code" when
+linting based exit codes are active.
+
+Not having a linter based exit code can be useful if you want to run the tool programmatically
+to perform the action and you only want the exit code to tell whether there was a problem
+providing the results.
+
+If you rely on the exit code, you are recommended to explicitly pass the relevant variant of the
+flag even if the current default matches your wishes.
+
+=back
+
 =item lint
 
 I<< Note: This subcommand needs optional dependencies to work from B<Recommends> or B<Suggests> >>
diff --git a/src/debputy/commands/debputy_cmd/__main__.py b/src/debputy/commands/debputy_cmd/__main__.py
index 1a7a737..2d6519f 100644
--- a/src/debputy/commands/debputy_cmd/__main__.py
+++ b/src/debputy/commands/debputy_cmd/__main__.py
@@ -358,7 +358,6 @@ def parse_args() -> argparse.Namespace:
 )
 def _check_manifest(context: CommandContext) -> None:
     context.parse_manifest()
-    _info("No errors detected.")
 
 
 def _install_plugin_from_plugin_metadata(
diff --git a/src/debputy/commands/debputy_cmd/lint_and_lsp_cmds.py b/src/debputy/commands/debputy_cmd/lint_and_lsp_cmds.py
index 2f283e8..ea97665 100644
--- a/src/debputy/commands/debputy_cmd/lint_and_lsp_cmds.py
+++ b/src/debputy/commands/debputy_cmd/lint_and_lsp_cmds.py
@@ -2,6 +2,7 @@ import textwrap
 from argparse import BooleanOptionalAction
 
 from debputy.commands.debputy_cmd.context import ROOT_COMMAND, CommandContext, add_arg
+from debputy.lsp.lsp_reference_keyword import ALL_PUBLIC_NAMED_STYLES
 from debputy.util import _error
 
 
@@ -26,9 +27,9 @@ _EDITOR_SNIPPETS = {
                     '(debian-changelog-mode . ("debputy" "lsp" "server" "--ignore-language-ids")))
             (add-to-list 'eglot-server-programs
                     '(debian-copyright-mode . ("debputy" "lsp" "server" "--ignore-language-ids")))
-        ;; Requires elpa-dpkg-dev-el (>> 37.11)
-        ;;    (add-to-list 'eglot-server-programs
-        ;;            '(debian-autopkgtest-control-mode . ("debputy" "lsp" "server" "--ignore-language-ids")))
+        ;; Requires elpa-dpkg-dev-el (>= 37.12)
+           (add-to-list 'eglot-server-programs
+                    '(debian-autopkgtest-control-mode . ("debputy" "lsp" "server" "--ignore-language-ids")))
             ;; The debian/rules file uses the qmake mode.
             (add-to-list 'eglot-server-programs
                     '(makefile-gmake-mode . ("debputy" "lsp" "server" "--ignore-language-ids")))
@@ -38,13 +39,15 @@ _EDITOR_SNIPPETS = {
 
         ;; Auto-start eglot for the relevant modes.
         (add-hook 'debian-control-mode-hook 'eglot-ensure)
-        ;; NOTE: changelog disabled by default because for some reason it
-        ;;       this hook causes perceivable delay (several seconds) when
-        ;;       opening the first changelog. It seems to be related to imenu.
-        ;; (add-hook 'debian-changelog-mode-hook 'eglot-ensure)
+        ;; Requires elpa-dpkg-dev-el (>= 37.12)
+        ;;   Technically, the `eglot-ensure` works before then, but it causes a
+        ;;   visible and very annoying long delay on opening the first changelog.
+        ;;   It still has a minor delay in 37.12, which may still be too long for
+        ;;   for your preference. In that case, comment it out.
+        (add-hook 'debian-changelog-mode-hook 'eglot-ensure)
         (add-hook 'debian-copyright-mode-hook 'eglot-ensure)
-        ;; Requires elpa-dpkg-dev-el (>> 37.11)
-        ;; (add-hook 'debian-autopkgtest-control-mode-hook 'eglot-ensure)
+        ;; Requires elpa-dpkg-dev-el (>= 37.12)
+        (add-hook 'debian-autopkgtest-control-mode-hook 'eglot-ensure)
         (add-hook 'makefile-gmake-mode-hook 'eglot-ensure)
         (add-hook 'yaml-mode-hook 'eglot-ensure)
     """
@@ -178,6 +181,8 @@ def lsp_server_cmd(context: CommandContext) -> None:
     debputy_language_server.dctrl_parser = context.dctrl_parser
     debputy_language_server.trust_language_ids = parsed_args.trust_language_ids
 
+    debputy_language_server.finish_initialization()
+
     if parsed_args.tcp and parsed_args.ws:
         _error("Sorry, --tcp and --ws are mutually exclusive")
 
@@ -254,7 +259,6 @@ def lsp_describe_features(context: CommandContext) -> None:
             "--auto-fix",
             dest="auto_fix",
             action="store_true",
-            shared=True,
             help="Automatically fix problems with trivial or obvious corrections.",
         ),
         add_arg(
@@ -264,6 +268,13 @@ def lsp_describe_features(context: CommandContext) -> None:
             action=BooleanOptionalAction,
             help='Enable or disable the "linter" convention of exiting with an error if severe issues were found',
         ),
+        add_arg(
+            "--warn-about-check-manifest",
+            dest="warn_about_check_manifest",
+            default=True,
+            action=BooleanOptionalAction,
+            help="Warn about limitations that check-manifest would cover if d/debputy.manifest is present",
+        ),
     ],
 )
 def lint_cmd(context: CommandContext) -> None:
@@ -278,9 +289,48 @@ def lint_cmd(context: CommandContext) -> None:
     perform_linting(context)
 
 
+@ROOT_COMMAND.register_subcommand(
+    "reformat",
+    argparser=[
+        add_arg(
+            "--style",
+            dest="named_style",
+            choices=ALL_PUBLIC_NAMED_STYLES,
+            default=None,
+            help="The formatting style to use (overrides packaging style).",
+        ),
+        add_arg(
+            "--auto-fix",
+            dest="auto_fix",
+            default=True,
+            action=BooleanOptionalAction,
+            help="Whether to automatically apply any style changes.",
+        ),
+        add_arg(
+            "--linter-exit-code",
+            dest="linter_exit_code",
+            default=True,
+            action=BooleanOptionalAction,
+            help='Enable or disable the "linter" convention of exiting with an error if issues were found',
+        ),
+    ],
+)
+def reformat_cmd(context: CommandContext) -> None:
+    try:
+        import lsprotocol
+    except ImportError:
+        _error("This feature requires lsprotocol (apt-get install python3-lsprotocol)")
+
+    from debputy.linting.lint_impl import perform_reformat
+
+    context.must_be_called_in_source_root()
+    perform_reformat(context, named_style=context.parsed_args.named_style)
+
+
 def ensure_lint_and_lsp_commands_are_loaded():
     # Loading the module does the heavy lifting
     # However, having this function means that we do not have an "unused" import that some tool
     # gets tempted to remove
     assert ROOT_COMMAND.has_command("lsp")
     assert ROOT_COMMAND.has_command("lint")
+    assert ROOT_COMMAND.has_command("reformat")
diff --git a/src/debputy/commands/debputy_cmd/output.py b/src/debputy/commands/debputy_cmd/output.py
index 2e117ba..5159980 100644
--- a/src/debputy/commands/debputy_cmd/output.py
+++ b/src/debputy/commands/debputy_cmd/output.py
@@ -22,6 +22,14 @@ from debputy.util import assume_not_none
 
 try:
     import colored
+
+    if (
+        not hasattr(colored, "Style")
+        or not hasattr(colored, "Fore")
+        or not hasattr(colored, "Back")
+    ):
+        # Seen with python3-colored v1 (bookworm)
+        raise ImportError
 except ImportError:
     colored = None
 
diff --git a/src/debputy/deb_packaging_support.py b/src/debputy/deb_packaging_support.py
index 6de61b4..8ab0484 100644
--- a/src/debputy/deb_packaging_support.py
+++ b/src/debputy/deb_packaging_support.py
@@ -1216,7 +1216,7 @@ def setup_control_files(
         return
 
     if generated_triggers:
-        assert not allow_ctrl_file_management
+        assert allow_ctrl_file_management
         dest_file = os.path.join(control_output_dir, "triggers")
         with open(dest_file, "at", encoding="utf-8") as fd:
             fd.writelines(
diff --git a/src/debputy/linting/lint_impl.py b/src/debputy/linting/lint_impl.py
index ec13d53..c4e9310 100644
--- a/src/debputy/linting/lint_impl.py
+++ b/src/debputy/linting/lint_impl.py
@@ -1,6 +1,7 @@
 import dataclasses
 import os
 import stat
+import subprocess
 import sys
 from typing import Optional, List, Union, NoReturn, Mapping
 
@@ -23,19 +24,35 @@ from debputy.linting.lint_util import (
     LinterImpl,
     LintReport,
     LintStateImpl,
+    FormatterImpl,
 )
 from debputy.lsp.lsp_debian_changelog import _lint_debian_changelog
-from debputy.lsp.lsp_debian_control import _lint_debian_control
-from debputy.lsp.lsp_debian_copyright import _lint_debian_copyright
+from debputy.lsp.lsp_debian_control import (
+    _lint_debian_control,
+    _reformat_debian_control,
+)
+from debputy.lsp.lsp_debian_copyright import (
+    _lint_debian_copyright,
+    _reformat_debian_copyright,
+)
 from debputy.lsp.lsp_debian_debputy_manifest import _lint_debian_debputy_manifest
 from debputy.lsp.lsp_debian_rules import _lint_debian_rules_impl
-from debputy.lsp.lsp_debian_tests_control import _lint_debian_tests_control
+from debputy.lsp.lsp_debian_tests_control import (
+    _lint_debian_tests_control,
+    _reformat_debian_tests_control,
+)
 from debputy.lsp.quickfixes import provide_standard_quickfixes_from_diagnostics
 from debputy.lsp.spellchecking import disable_spellchecking
+from debputy.lsp.style_prefs import (
+    StylePreferenceTable,
+    EffectivePreference,
+    determine_effective_style,
+)
 from debputy.lsp.text_edit import (
     get_well_formatted_edit,
     merge_sort_text_edits,
     apply_text_edits,
+    OverLappingTextEditException,
 )
 from debputy.packages import SourcePackage, BinaryPackage
 from debputy.plugin.api.feature_set import PluginProvidedFeatureSet
@@ -51,24 +68,39 @@ LINTER_FORMATS = {
 }
 
 
+REFORMAT_FORMATS = {
+    "debian/control": _reformat_debian_control,
+    "debian/copyright": _reformat_debian_copyright,
+    "debian/tests/control": _reformat_debian_tests_control,
+}
+
+
 @dataclasses.dataclass(slots=True)
 class LintContext:
     plugin_feature_set: PluginProvidedFeatureSet
+    style_preference_table: StylePreferenceTable
     source_package: Optional[SourcePackage] = None
     binary_packages: Optional[Mapping[str, BinaryPackage]] = None
+    effective_preference: Optional[EffectivePreference] = None
 
-    def state_for(self, path, lines) -> LintStateImpl:
+    def state_for(self, path: str, content: str, lines: List[str]) -> LintStateImpl:
         return LintStateImpl(
             self.plugin_feature_set,
+            self.style_preference_table,
             path,
+            content,
             lines,
             self.source_package,
             self.binary_packages,
+            self.effective_preference,
         )
 
 
 def gather_lint_info(context: CommandContext) -> LintContext:
-    lint_context = LintContext(context.load_plugins())
+    lint_context = LintContext(
+        context.load_plugins(),
+        StylePreferenceTable.load_styles(),
+    )
     try:
         with open("debian/control") as fd:
             source_package, binary_packages = (
@@ -76,6 +108,11 @@ def gather_lint_info(context: CommandContext) -> LintContext:
             )
         lint_context.source_package = source_package
         lint_context.binary_packages = binary_packages
+        if source_package is not None:
+            lint_context.effective_preference = determine_effective_style(
+                lint_context.style_preference_table,
+                source_package,
+            )
     except FileNotFoundError:
         pass
 
@@ -112,7 +149,9 @@ def perform_linting(context: CommandContext) -> None:
             "Some sub-linters reported issues. Please report the bug and include the output"
         )
 
-    if os.path.isfile("debian/debputy.manifest"):
+    if parsed_args.warn_about_check_manifest and os.path.isfile(
+        "debian/debputy.manifest"
+    ):
         _info("Note: Due to a limitation in the linter, debian/debputy.manifest is")
         _info("only **partially** checked by this command at the time of writing.")
         _info("Please use `debputy check-manifest` to fully check the manifest.")
@@ -121,6 +160,129 @@ def perform_linting(context: CommandContext) -> None:
         _exit_with_lint_code(lint_report)
 
 
+def perform_reformat(
+    context: CommandContext,
+    *,
+    named_style: Optional[str] = None,
+) -> None:
+    parsed_args = context.parsed_args
+    if not parsed_args.spellcheck:
+        disable_spellchecking()
+    fo = _output_styling(context.parsed_args, sys.stdout)
+    lint_context = gather_lint_info(context)
+    if named_style is not None:
+        style = lint_context.style_preference_table.named_styles.get(named_style)
+        if style is None:
+            styles = ", ".join(lint_context.style_preference_table.named_styles)
+            _error(f'There is no style named "{style}". Options include: {styles}')
+        if (
+            lint_context.effective_preference is not None
+            and lint_context.effective_preference != style
+        ):
+            _info(
+                f'Note that the style "{named_style}" does not match the style that `debputy` was configured to use.'
+            )
+            _info("This may be a non-issue (if the configuration is out of date).")
+        lint_context.effective_preference = style
+
+    if lint_context.effective_preference is None:
+        _info(
+            "You can set `X-Style: black` in the source stanza of `debian/control` to pick"
+        )
+        _info("`black` as the preferred style for this package.")
+        _info("")
+        _info(
+            "You can also include your style in `debputy`. This has the advantage that `debputy`"
+        )
+        _info(
+            "can sometimes automatically derive an agreed style between all maintainers and"
+        )
+        _info(
+            "co-maintainers for informal teams (provided all agree to the same style), where"
+        )
+        _info(
+            "no explicit synchronization has been done (that is, there is no `X-Style` field)"
+        )
+        _info("")
+        _info(
+            "For packaging teams, you can also have a team style that is applied to all team"
+        )
+        _info("maintained packages by having it recorded in `debputy`.")
+        _error("Sorry; `debputy` does not know which style to use for this package.")
+
+    changes = False
+    auto_fix = context.parsed_args.auto_fix
+    for name_stem in REFORMAT_FORMATS:
+        formatter = REFORMAT_FORMATS.get(name_stem)
+        filename = f"./{name_stem}"
+        if formatter is None or not os.path.isfile(filename):
+            continue
+
+        reformatted = perform_reformat_of_file(
+            fo,
+            lint_context,
+            filename,
+            formatter,
+            auto_fix,
+        )
+        if reformatted:
+            changes = True
+
+    if changes and parsed_args.linter_exit_code:
+        sys.exit(2)
+
+
+def perform_reformat_of_file(
+    fo: OutputStylingBase,
+    lint_context: LintContext,
+    filename: str,
+    formatter: FormatterImpl,
+    auto_fix: bool,
+) -> bool:
+    with open(filename, "rt", encoding="utf-8") as fd:
+        text = fd.read()
+
+    lines = text.splitlines(keepends=True)
+    lint_state = lint_context.state_for(
+        filename,
+        text,
+        lines,
+    )
+    edits = formatter(lint_state)
+    if not edits:
+        return False
+
+    try:
+        replacement = apply_text_edits(text, lines, edits)
+    except OverLappingTextEditException:
+        _error(
+            f"The reformatter for {filename} produced overlapping edits (which is broken and will not work)"
+        )
+
+    output_filename = f"{filename}.tmp"
+    with open(output_filename, "wt", encoding="utf-8") as fd:
+        fd.write(replacement)
+
+    r = subprocess.run(["diff", "-u", filename, output_filename]).returncode
+    if r != 0 and r != 1:
+        _warn(f"diff -u {filename} {output_filename} failed!?")
+    if auto_fix:
+        orig_mode = stat.S_IMODE(os.stat(filename).st_mode)
+        os.chmod(output_filename, orig_mode)
+        os.rename(output_filename, filename)
+        print(
+            fo.colored(
+                f"Reformatted {filename}.",
+                fg="green",
+                style="bold",
+            )
+        )
+    else:
+        os.unlink(output_filename)
+
+    return True
+
+
 def _exit_with_lint_code(lint_report: LintReport) -> NoReturn:
     diagnostics_count = lint_report.diagnostics_count
     if (
@@ -193,6 +355,7 @@ def _auto_fix_run(
     lines = text.splitlines(keepends=True)
     lint_state = lint_context.state_for(
         filename,
+        text,
         lines,
     )
     current_issues = linter(lint_state)
@@ -346,7 +509,7 @@ def _diagnostics_run(
     lint_report: LintReport,
 ) -> None:
     lines = text.splitlines(keepends=True)
-    lint_state = lint_context.state_for(filename, lines)
+    lint_state = lint_context.state_for(filename, text, lines)
     issues = linter(lint_state) or []
     for diagnostic in issues:
         actions = provide_standard_quickfixes_from_diagnostics(
diff --git a/src/debputy/linting/lint_util.py b/src/debputy/linting/lint_util.py
index 8f226fa..e997097 100644
--- a/src/debputy/linting/lint_util.py
+++ b/src/debputy/linting/lint_util.py
@@ -1,8 +1,8 @@
 import dataclasses
 import os
-from typing import List, Optional, Callable, Counter, TYPE_CHECKING, Mapping
+from typing import List, Optional, Callable, Counter, TYPE_CHECKING, Mapping, Sequence
 
-from lsprotocol.types import Position, Range, Diagnostic, DiagnosticSeverity
+from lsprotocol.types import Position, Range, Diagnostic, DiagnosticSeverity, TextEdit
 
 from debputy.commands.debputy_cmd.output import OutputStylingBase
 from debputy.packages import SourcePackage, BinaryPackage
@@ -11,9 +11,14 @@ from debputy.util import _DEFAULT_LOGGER, _warn
 
 if TYPE_CHECKING:
     from debputy.lsp.text_util import LintCapablePositionCodec
+    from debputy.lsp.style_prefs import (
+        StylePreferenceTable,
+        EffectivePreference,
+    )
 
 
 LinterImpl = Callable[["LintState"], Optional[List[Diagnostic]]]
+FormatterImpl = Callable[["LintState"], Optional[Sequence[TextEdit]]]
 
 
 class LintState:
@@ -31,6 +36,10 @@ class LintState:
         raise NotImplementedError
 
     @property
+    def content(self) -> str:
+        raise NotImplementedError
+
+    @property
     def lines(self) -> List[str]:
         raise NotImplementedError
 
@@ -46,14 +55,25 @@ class LintState:
     def binary_packages(self) -> Optional[Mapping[str, BinaryPackage]]:
         raise NotImplementedError
 
+    @property
+    def style_preference_table(self) -> "StylePreferenceTable":
+        raise NotImplementedError
+
+    @property
+    def effective_preference(self) -> Optional["EffectivePreference"]:
+        raise NotImplementedError
+
 
 @dataclasses.dataclass(slots=True)
 class LintStateImpl(LintState):
     plugin_feature_set: PluginProvidedFeatureSet = dataclasses.field(repr=False)
+    style_preference_table: "StylePreferenceTable" = dataclasses.field(repr=False)
     path: str
+    content: str
     lines: List[str]
-    source_package: Optional[SourcePackage]
-    binary_packages: Optional[Mapping[str, BinaryPackage]]
+    source_package: Optional[SourcePackage] = None
+    binary_packages: Optional[Mapping[str, BinaryPackage]] = None
+    effective_preference: Optional["EffectivePreference"] = None
 
     @property
     def doc_uri(self) -> str:
diff --git a/src/debputy/lsp/debputy_ls.py b/src/debputy/lsp/debputy_ls.py
index cc3f00e..e475ab4 100644
--- a/src/debputy/lsp/debputy_ls.py
+++ b/src/debputy/lsp/debputy_ls.py
@@ -13,7 +13,14 @@ from typing import (
 
 from lsprotocol.types import MarkupKind
 
-from debputy.linting.lint_util import LintState
+from debputy.linting.lint_util import (
+    LintState,
+)
+from debputy.lsp.style_prefs import (
+    StylePreferenceTable,
+    MaintainerPreference,
+    determine_effective_style,
+)
 from debputy.lsp.text_util import LintCapablePositionCodec
 from debputy.packages import (
     SourcePackage,
@@ -21,6 +28,7 @@ from debputy.packages import (
     DctrlParser,
 )
 from debputy.plugin.api.feature_set import PluginProvidedFeatureSet
+from debputy.util import _info
 
 if TYPE_CHECKING:
     from pygls.server import LanguageServer
@@ -89,6 +97,10 @@ class LSProvidedLintState(LintState):
         return self._doc.path
 
     @property
+    def content(self) -> str:
+        return self._doc.source
+
+    @property
     def lines(self) -> List[str]:
         return self._lines
 
@@ -146,6 +158,17 @@ class LSProvidedLintState(LintState):
         dctrl = self._resolve_dctrl()
         return dctrl.binary_packages if dctrl is not None else None
 
+    @property
+    def effective_preference(self) -> Optional[MaintainerPreference]:
+        source_package = self.source_package
+        if source_package is None:
+            return None
+        return determine_effective_style(self.style_preference_table, source_package)
+
+    @property
+    def style_preference_table(self) -> StylePreferenceTable:
+        return self._ls.style_preferences
+
 
 def _preference(
     client_preference: Optional[List[MarkupKind]],
@@ -171,6 +194,20 @@ class DebputyLanguageServer(LanguageServer):
         self._dctrl_parser: Optional[DctrlParser] = None
         self._plugin_feature_set: Optional[PluginProvidedFeatureSet] = None
         self._trust_language_ids: Optional[bool] = None
+        self._finished_initialization = False
+        self.style_preferences = StylePreferenceTable({}, {})
+
+    def finish_initialization(self) -> None:
+        if self._finished_initialization:
+            return
+        assert self._dctrl_parser is not None
+        assert self._plugin_feature_set is not None
+        assert self._trust_language_ids is not None
+        self.style_preferences = self.style_preferences.load_styles()
+        _info(
+            f"Loaded style preferences: {len(self.style_preferences.maintainer_preferences)} unique maintainer preferences recorded"
+        )
+        self._finished_initialization = True
 
     @property
     def plugin_feature_set(self) -> PluginProvidedFeatureSet:
diff --git a/src/debputy/lsp/diagnostics.py b/src/debputy/lsp/diagnostics.py
new file mode 100644
index 0000000..6e0b88a
--- /dev/null
+++ b/src/debputy/lsp/diagnostics.py
@@ -0,0 +1,8 @@
+from typing import TypedDict, NotRequired, List, Any, Literal, Optional
+
+LintSeverity = Literal["style"]
+
+
+class DiagnosticData(TypedDict):
+    quickfixes: NotRequired[Optional[List[Any]]]
+    lint_severity: NotRequired[Optional[LintSeverity]]
diff --git a/src/debputy/lsp/lsp_debian_changelog.py b/src/debputy/lsp/lsp_debian_changelog.py
index ecff192..c6166c5 100644
--- a/src/debputy/lsp/lsp_debian_changelog.py
+++ b/src/debputy/lsp/lsp_debian_changelog.py
@@ -23,6 +23,7 @@ from lsprotocol.types import (
 )
 
 from debputy.linting.lint_util import LintState
+from debputy.lsp.diagnostics import DiagnosticData
 from debputy.lsp.lsp_features import lsp_diagnostics, lsp_standard_handler
 from debputy.lsp.quickfixes import (
     propose_correct_text_quick_fix,
@@ -64,23 +65,6 @@ _WEEKDAYS_BY_IDX = [
 ]
 _KNOWN_WEEK_DAYS = frozenset(_WEEKDAYS_BY_IDX)
 
-DOCUMENT_VERSION_TABLE: Dict[str, int] = {}
-
-
-def _handle_close(
-    ls: "LanguageServer",
-    params: DidCloseTextDocumentParams,
-) -> None:
-    try:
-        del DOCUMENT_VERSION_TABLE[params.text_document.uri]
-    except KeyError:
-        pass
-
-
-def is_doc_at_version(uri: str, version: int) -> bool:
-    dv = DOCUMENT_VERSION_TABLE.get(uri)
-    return dv == version
-
 
 lsp_standard_handler(_LANGUAGE_IDS, TEXT_DOCUMENT_CODE_ACTION)
 lsp_standard_handler(_LANGUAGE_IDS, TEXT_DOCUMENT_WILL_SAVE_WAIT_UNTIL)
@@ -212,7 +196,9 @@ def _check_footer_line(
             f"The date was a {expected_week_day}day.",
             severity=DiagnosticSeverity.Warning,
             source="debputy",
-            data=[propose_correct_text_quick_fix(expected_week_day)],
+            data=DiagnosticData(
+                quickfixes=[propose_correct_text_quick_fix(expected_week_day)]
+            ),
         )
 
 
@@ -232,8 +218,9 @@ def _check_header_line(
     if (
         entry_no == 1
         and dctrl_source_pkg is not None
-        and dctrl_source_pkg.name != source_name
+        and dctrl_source_pkg.fields.get("Source") != source_name
     ):
+        expected_name = dctrl_source_pkg.fields.get("Source") or "(missing)"
         start_pos, end_pos = m.span(1)
         range_server_units = Range(
             Position(
@@ -248,7 +235,7 @@ def _check_header_line(
         yield Diagnostic(
             position_codec.range_to_client_units(lint_state.lines, range_server_units),
             f"The first entry must use the same source name as debian/control."
-            f' Changelog uses: "{source_name}" while d/control uses: "{dctrl_source_pkg.name}"',
+            f' Changelog uses: "{source_name}" while d/control uses: "{expected_name}"',
             severity=DiagnosticSeverity.Error,
             source="debputy",
         )
diff --git a/src/debputy/lsp/lsp_debian_control.py b/src/debputy/lsp/lsp_debian_control.py
index b44e8f9..3a4107b 100644
--- a/src/debputy/lsp/lsp_debian_control.py
+++ b/src/debputy/lsp/lsp_debian_control.py
@@ -6,43 +6,22 @@ from typing import (
     Union,
     Sequence,
     Tuple,
-    Iterator,
     Optional,
-    Iterable,
     Mapping,
     List,
-    FrozenSet,
     Dict,
 )
 
-from debputy.lsp.debputy_ls import DebputyLanguageServer
-from lsprotocol.types import (
-    DiagnosticSeverity,
-    Range,
-    Diagnostic,
-    Position,
-    FoldingRange,
-    FoldingRangeParams,
-    CompletionItem,
-    CompletionList,
-    CompletionParams,
-    TEXT_DOCUMENT_WILL_SAVE_WAIT_UNTIL,
-    DiagnosticRelatedInformation,
-    Location,
-    HoverParams,
-    Hover,
-    TEXT_DOCUMENT_CODE_ACTION,
-    SemanticTokens,
-    SemanticTokensParams,
-)
-
 from debputy.linting.lint_util import LintState
+from debputy.lsp.debputy_ls import DebputyLanguageServer
+from debputy.lsp.diagnostics import DiagnosticData
 from debputy.lsp.lsp_debian_control_reference_data import (
     DctrlKnownField,
     BINARY_FIELDS,
     SOURCE_FIELDS,
     DctrlFileMetadata,
     package_name_to_section,
+    all_package_relationship_fields,
 )
 from debputy.lsp.lsp_features import (
     lint_diagnostics,
@@ -51,6 +30,8 @@ from debputy.lsp.lsp_features import (
     lsp_standard_handler,
     lsp_folding_ranges,
     lsp_semantic_tokens_full,
+    lsp_will_save_wait_until,
+    lsp_format_document,
 )
 from debputy.lsp.lsp_generic_deb822 import (
     deb822_completer,
@@ -58,6 +39,7 @@ from debputy.lsp.lsp_generic_deb822 import (
     deb822_folding_ranges,
     deb822_semantic_tokens_full,
     deb822_token_iter,
+    deb822_format_file,
 )
 from debputy.lsp.quickfixes import (
     propose_remove_line_quick_fix,
@@ -81,10 +63,28 @@ from debputy.lsp.vendoring._deb822_repro.parsing import (
     Deb822KeyValuePairElement,
     LIST_SPACE_SEPARATED_INTERPRETATION,
 )
-from debputy.lsp.vendoring._deb822_repro.tokens import (
-    Deb822Token,
+from lsprotocol.types import (
+    DiagnosticSeverity,
+    Range,
+    Diagnostic,
+    Position,
+    FoldingRange,
+    FoldingRangeParams,
+    CompletionItem,
+    CompletionList,
+    CompletionParams,
+    TEXT_DOCUMENT_WILL_SAVE_WAIT_UNTIL,
+    DiagnosticRelatedInformation,
+    Location,
+    HoverParams,
+    Hover,
+    TEXT_DOCUMENT_CODE_ACTION,
+    SemanticTokens,
+    SemanticTokensParams,
+    WillSaveTextDocumentParams,
+    TextEdit,
+    DocumentFormattingParams,
 )
-from debputy.util import _info
 
 try:
     from debputy.lsp.vendoring._deb822_repro.locatable import (
@@ -126,7 +126,7 @@ class SubstvarMetadata:
 
 
 def relationship_substvar_for_field(substvar: str) -> Optional[str]:
-    relationship_fields = _relationship_fields()
+    relationship_fields = all_package_relationship_fields()
     try:
         col_idx = substvar.rindex(":")
     except ValueError:
@@ -287,28 +287,6 @@ _DCTRL_FILE_METADATA = DctrlFileMetadata()
 
 
 lsp_standard_handler(_LANGUAGE_IDS, TEXT_DOCUMENT_CODE_ACTION)
-lsp_standard_handler(_LANGUAGE_IDS, TEXT_DOCUMENT_WILL_SAVE_WAIT_UNTIL)
-
-
-@lru_cache
-def _relationship_fields() -> Mapping[str, str]:
-    # TODO: Pull from `dpkg-dev` when possible fallback only to the static list.
-    return {
-        f.lower(): f
-        for f in (
-            "Pre-Depends",
-            "Depends",
-            "Recommends",
-            "Suggests",
-            "Enhances",
-            "Conflicts",
-            "Breaks",
-            "Replaces",
-            "Provides",
-            "Built-Using",
-            "Static-Built-Using",
-        )
-    }
 
 
 @lsp_hover(_LANGUAGE_IDS)
@@ -539,7 +517,7 @@ def _binary_package_checks(
                 f'The Section should be "{component_prefix}{guessed_section}"{section_diagnostic_rationale}',
                 severity=DiagnosticSeverity.Warning,
                 source="debputy",
-                data=quickfix_data,
+                data=DiagnosticData(quickfixes=quickfix_data),
             )
         )
 
@@ -557,17 +535,12 @@ def _diagnostics_for_paragraph(
     diagnostics: List[Diagnostic],
 ) -> None:
     representation_field = _paragraph_representation_field(stanza)
-    representation_field_pos = representation_field.position_in_parent().relative_to(
+    representation_field_range = representation_field.range_in_parent().relative_to(
         stanza_position
     )
-    representation_field_range_server_units = te_range_to_lsp(
-        TERange.from_position_and_size(
-            representation_field_pos, representation_field.size()
-        )
-    )
     representation_field_range = position_codec.range_to_client_units(
         lines,
-        representation_field_range_server_units,
+        te_range_to_lsp(representation_field_range),
     )
     for known_field in known_fields.values():
         missing_field_severity = known_field.missing_field_severity
@@ -606,7 +579,10 @@ def _diagnostics_for_paragraph(
         normalized_field_name_lc = normalize_dctrl_field_name(field_name_lc)
         known_field = known_fields.get(normalized_field_name_lc)
         field_value = stanza[field_name]
-        field_range_te = kvpair.range_in_parent().relative_to(stanza_position)
+        kvpair_position = kvpair.position_in_parent().relative_to(stanza_position)
+        field_range_te = kvpair.field_token.range_in_parent().relative_to(
+            kvpair_position
+        )
         field_position_te = field_range_te.start_pos
         field_range_server_units = te_range_to_lsp(field_range_te)
         field_range = position_codec.range_to_client_units(
@@ -646,10 +622,12 @@ def _diagnostics_for_paragraph(
                         f'The "{field_name}" looks like a typo of "{known_field.name}".',
                         severity=DiagnosticSeverity.Warning,
                         source="debputy",
-                        data=[
-                            propose_correct_text_quick_fix(known_fields[m].name)
-                            for m in candidates
-                        ],
+                        data=DiagnosticData(
+                            quickfixes=[
+                                propose_correct_text_quick_fix(known_fields[m].name)
+                                for m in candidates
+                            ]
+                        ),
                     )
                 )
         if known_field is None:
@@ -682,6 +660,7 @@ def _diagnostics_for_paragraph(
                 kvpair,
                 stanza,
                 stanza_position,
+                kvpair_position,
                 position_codec,
                 lines,
                 field_name_typo_reported=field_name_typo_detected,
@@ -722,9 +701,12 @@ def _diagnostics_for_paragraph(
                             f'Spelling "{word}"',
                             severity=DiagnosticSeverity.Hint,
                             source="debputy",
-                            data=[
-                                propose_correct_text_quick_fix(c) for c in corrections
-                            ],
+                            data=DiagnosticData(
+                                quickfixes=[
+                                    propose_correct_text_quick_fix(c)
+                                    for c in corrections
+                                ]
+                            ),
                         )
                     )
         source_value = source_stanza.get(field_name)
@@ -750,7 +732,7 @@ def _diagnostics_for_paragraph(
                     f"The field {field_name} duplicates the value from the Source stanza.",
                     severity=DiagnosticSeverity.Information,
                     source="debputy",
-                    data=fix_data,
+                    data=DiagnosticData(quickfixes=fix_data),
                 )
             )
     for (
@@ -846,7 +828,11 @@ def _scan_for_syntax_errors_and_token_level_diagnostics(
                         f'Spelling "{word}"',
                         severity=DiagnosticSeverity.Hint,
                         source="debputy",
-                        data=[propose_correct_text_quick_fix(c) for c in corrections],
+                        data=DiagnosticData(
+                            quickfixes=[
+                                propose_correct_text_quick_fix(c) for c in corrections
+                            ]
+                        ),
                     )
                 )
     return first_error
@@ -903,6 +889,32 @@ def _lint_debian_control(
     return diagnostics
 
 
+@lsp_will_save_wait_until(_LANGUAGE_IDS)
+def _debian_control_on_save_formatting(
+    ls: "DebputyLanguageServer",
+    params: WillSaveTextDocumentParams,
+) -> Optional[Sequence[TextEdit]]:
+    doc = ls.workspace.get_text_document(params.text_document.uri)
+    lint_state = ls.lint_state(doc)
+    return _reformat_debian_control(lint_state)
+
+
+def _reformat_debian_control(
+    lint_state: LintState,
+) -> Optional[Sequence[TextEdit]]:
+    return deb822_format_file(lint_state, _DCTRL_FILE_METADATA)
+
+
+@lsp_format_document(_LANGUAGE_IDS)
+def _debian_control_on_save_formatting(
+    ls: "DebputyLanguageServer",
+    params: DocumentFormattingParams,
+) -> Optional[Sequence[TextEdit]]:
+    doc = ls.workspace.get_text_document(params.text_document.uri)
+    lint_state = ls.lint_state(doc)
+    return deb822_format_file(lint_state, _DCTRL_FILE_METADATA)
+
+
 @lsp_semantic_tokens_full(_LANGUAGE_IDS)
 def _debian_control_semantic_tokens_full(
     ls: "DebputyLanguageServer",
diff --git a/src/debputy/lsp/lsp_debian_control_reference_data.py b/src/debputy/lsp/lsp_debian_control_reference_data.py
index 898faab..60e47d7 100644
--- a/src/debputy/lsp/lsp_debian_control_reference_data.py
+++ b/src/debputy/lsp/lsp_debian_control_reference_data.py
@@ -1,6 +1,7 @@
 import dataclasses
 import functools
 import itertools
+import operator
 import re
 import sys
 import textwrap
@@ -19,18 +20,39 @@ from typing import (
     Callable,
     Tuple,
     Any,
+    Set,
+    TYPE_CHECKING,
 )
 
+from debian._deb822_repro.types import TE
 from debian.debian_support import DpkgArchTable
+from lsprotocol.types import (
+    DiagnosticSeverity,
+    Diagnostic,
+    DiagnosticTag,
+    Range,
+    TextEdit,
+    Position,
+)
+
+from debputy.lsp.diagnostics import DiagnosticData
+
+from debputy.lsp.lsp_reference_keyword import (
+    ALL_PUBLIC_NAMED_STYLES,
+    Keyword,
+    allowed_values,
+)
 from debputy.lsp.quickfixes import (
     propose_correct_text_quick_fix,
     propose_remove_line_quick_fix,
 )
+from debputy.lsp.text_edit import apply_text_edits
 from debputy.lsp.text_util import (
     normalize_dctrl_field_name,
     LintCapablePositionCodec,
     detect_possible_typo,
     te_range_to_lsp,
+    trim_end_of_line_whitespace,
 )
 from debputy.lsp.vendoring._deb822_repro.parsing import (
     Deb822KeyValuePairElement,
@@ -44,6 +66,7 @@ from debputy.lsp.vendoring._deb822_repro.parsing import (
     Deb822ParsedValueElement,
     LIST_UPLOADERS_INTERPRETATION,
     _parse_whitespace_list_value,
+    parse_deb822_file,
 )
 from debputy.lsp.vendoring._deb822_repro.tokens import (
     Deb822FieldNameToken,
@@ -53,8 +76,9 @@ from debputy.lsp.vendoring._deb822_repro.tokens import (
     _RE_WHITESPACE_SEPARATED_WORD_LIST,
     Deb822SpaceSeparatorToken,
 )
+from debputy.lsp.vendoring._deb822_repro.types import FormatterCallback
+from debputy.lsp.vendoring.wrap_and_sort import _sort_packages_key
 from debputy.util import PKGNAME_REGEX
-from lsprotocol.types import DiagnosticSeverity, Diagnostic, DiagnosticTag, Range
 
 try:
     from debputy.lsp.vendoring._deb822_repro.locatable import (
@@ -66,6 +90,10 @@ except ImportError:
     pass
 
 
+if TYPE_CHECKING:
+    from debputy.lsp.style_prefs import EffectivePreference
+
+
 F = TypeVar("F", bound="Deb822KnownField")
 S = TypeVar("S", bound="StanzaMetadata")
 
@@ -103,7 +131,7 @@ LIST_COMMA_OR_SPACE_SEPARATED_INTERPRETATION = ListInterpretation(
     _parse_whitespace_list_value,
     Deb822ParsedValueElement,
     Deb822SpaceSeparatorToken,
-    Deb822SpaceSeparatorToken,
+    lambda: Deb822SpaceSeparatorToken(","),
     _parsed_value_render_factory,
 )
 
@@ -121,6 +149,43 @@ CustomFieldCheck = Callable[
 ]
 
 
+@functools.lru_cache
+def all_package_relationship_fields() -> Mapping[str, str]:
+    # TODO: Pull from `dpkg-dev` when possible fallback only to the static list.
+    return {
+        f.lower(): f
+        for f in (
+            "Pre-Depends",
+            "Depends",
+            "Recommends",
+            "Suggests",
+            "Enhances",
+            "Conflicts",
+            "Breaks",
+            "Replaces",
+            "Provides",
+            "Built-Using",
+            "Static-Built-Using",
+        )
+    }
+
+
+@functools.lru_cache
+def all_source_relationship_fields() -> Mapping[str, str]:
+    # TODO: Pull from `dpkg-dev` when possible fallback only to the static list.
+    return {
+        f.lower(): f
+        for f in (
+            "Build-Depends",
+            "Build-Depends-Arch",
+            "Build-Depends-Indep",
+            "Build-Conflicts",
+            "Build-Conflicts-Arch",
+            "Build-Conflicts-Indep",
+        )
+    }
+
+
 ALL_SECTIONS_WITHOUT_COMPONENT = frozenset(
     [
         "admin",
@@ -199,28 +264,7 @@ def _fields(*fields: F) -> Mapping[str, F]:
     return {normalize_dctrl_field_name(f.name.lower()): f for f in fields}
 
 
-@dataclasses.dataclass(slots=True, frozen=True)
-class Keyword:
-    value: str
-    hover_text: Optional[str] = None
-    is_obsolete: bool = False
-    replaced_by: Optional[str] = None
-    is_exclusive: bool = False
-    """For keywords in fields that allow multiple keywords, the `is_exclusive` can be
-    used for keywords that cannot be used with other keywords. As an example, the `all`
-    value in `Architecture` of `debian/control` cannot be used with any other architecture.
-    """
-
-
-def _allowed_values(*values: Union[str, Keyword]) -> Mapping[str, Keyword]:
-    as_keywords = [k if isinstance(k, Keyword) else Keyword(k) for k in values]
-    as_mapping = {k.value: k for k in as_keywords if k.value}
-    # Simple bug check
-    assert len(as_keywords) == len(as_mapping)
-    return as_mapping
-
-
-ALL_SECTIONS = _allowed_values(
+ALL_SECTIONS = allowed_values(
     *[
         s if c is None else f"{c}/{s}"
         for c, s in itertools.product(
@@ -230,7 +274,7 @@ ALL_SECTIONS = _allowed_values(
     ]
 )
 
-ALL_PRIORITIES = _allowed_values(
+ALL_PRIORITIES = allowed_values(
     Keyword(
         "required",
         hover_text=textwrap.dedent(
@@ -762,17 +806,19 @@ class Deb822KnownField:
         kvpair: Deb822KeyValuePairElement,
         stanza: Deb822ParagraphElement,
         stanza_position: "TEPosition",
+        kvpair_position: "TEPosition",
         position_codec: "LintCapablePositionCodec",
         lines: List[str],
         *,
         field_name_typo_reported: bool = False,
     ) -> Iterable[Diagnostic]:
         field_name_token = kvpair.field_token
-        field_range_te = kvpair.range_in_parent().relative_to(stanza_position)
-        field_position_te = field_range_te.start_pos
+        field_range_te = kvpair.field_token.range_in_parent().relative_to(
+            kvpair_position
+        )
         yield from self._diagnostics_for_field_name(
             field_name_token,
-            field_position_te,
+            field_range_te,
             field_name_typo_reported,
             position_codec,
             lines,
@@ -789,13 +835,16 @@ class Deb822KnownField:
             )
         if not self.spellcheck_value:
             yield from self._known_value_diagnostics(
-                kvpair, field_position_te, position_codec, lines
+                kvpair,
+                kvpair_position,
+                position_codec,
+                lines,
             )
 
     def _diagnostics_for_field_name(
         self,
         token: Deb822FieldNameToken,
-        token_position: "TEPosition",
+        token_range: "TERange",
         typo_detected: bool,
         position_codec: "LintCapablePositionCodec",
         lines: List[str],
@@ -803,9 +852,7 @@ class Deb822KnownField:
         field_name = token.text
         # Defeat the case-insensitivity from python-debian
         field_name_cased = str(field_name)
-        token_range_server_units = te_range_to_lsp(
-            TERange.from_position_and_size(token_position, token.size())
-        )
+        token_range_server_units = te_range_to_lsp(token_range)
         token_range = position_codec.range_to_client_units(
             lines,
             token_range_server_units,
@@ -817,7 +864,7 @@ class Deb822KnownField:
                 severity=DiagnosticSeverity.Warning,
                 source="debputy",
                 tags=[DiagnosticTag.Deprecated],
-                data=propose_remove_line_quick_fix(),
+                data=DiagnosticData(quickfixes=[propose_remove_line_quick_fix()]),
             )
         elif self.replaced_by is not None:
             yield Diagnostic(
@@ -826,7 +873,9 @@ class Deb822KnownField:
                 severity=DiagnosticSeverity.Warning,
                 source="debputy",
                 tags=[DiagnosticTag.Deprecated],
-                data=propose_correct_text_quick_fix(self.replaced_by),
+                data=DiagnosticData(
+                    quickfixes=[propose_correct_text_quick_fix(self.replaced_by)],
+                ),
             )
 
         if not typo_detected and field_name_cased != self.name:
@@ -835,25 +884,52 @@ class Deb822KnownField:
                 f"Non-canonical spelling of {self.name}",
                 severity=DiagnosticSeverity.Information,
                 source="debputy",
-                data=propose_correct_text_quick_fix(self.name),
+                data=DiagnosticData(
+                    quickfixes=[propose_correct_text_quick_fix(self.name)]
+                ),
             )
 
     def _known_value_diagnostics(
         self,
         kvpair: Deb822KeyValuePairElement,
-        field_position_te: "TEPosition",
+        kvpair_position: "TEPosition",
         position_codec: "LintCapablePositionCodec",
         lines: List[str],
     ) -> Iterable[Diagnostic]:
         unknown_value_severity = self.unknown_value_diagnostic_severity
-        allowed_values = self.known_values
         interpreter = self.field_value_class.interpreter()
-        if not allowed_values or interpreter is None:
+        if interpreter is None:
             return
         values = kvpair.interpret_as(interpreter)
         value_off = kvpair.value_element.position_in_parent().relative_to(
-            field_position_te
+            kvpair_position
         )
+
+        last_token_non_ws_sep_token: Optional[TE] = None
+        for token in values.iter_parts():
+            if token.is_whitespace:
+                continue
+            if not token.is_separator:
+                last_token_non_ws_sep_token = None
+                continue
+            if last_token_non_ws_sep_token is not None:
+                sep_range_te = token.range_in_parent().relative_to(value_off)
+                value_range = position_codec.range_to_client_units(
+                    lines,
+                    te_range_to_lsp(sep_range_te),
+                )
+                yield Diagnostic(
+                    value_range,
+                    "Duplicate separator",
+                    severity=DiagnosticSeverity.Error,
+                    source="debputy",
+                )
+            last_token_non_ws_sep_token = token
+
+        allowed_values = self.known_values
+        if not allowed_values:
+            return
+
         first_value = None
         first_exclusive_value_ref = None
         first_exclusive_value = None
@@ -866,12 +942,8 @@ class Deb822KnownField:
                 and self.field_value_class == FieldValueClass.SINGLE_VALUE
             ):
                 value_loc = value_ref.locatable
-                value_position_te = value_loc.position_in_parent().relative_to(
-                    value_off
-                )
-                value_range_in_server_units = te_range_to_lsp(
-                    TERange.from_position_and_size(value_position_te, value_loc.size())
-                )
+                range_position_te = value_loc.range_in_parent().relative_to(value_off)
+                value_range_in_server_units = te_range_to_lsp(range_position_te)
                 value_range = position_codec.range_to_client_units(
                     lines,
                     value_range_in_server_units,
@@ -935,7 +1007,7 @@ class Deb822KnownField:
                         "message": unknown_value_message,
                         "severity": unknown_severity,
                         "source": "debputy",
-                        "data": typo_fix_data,
+                        "data": DiagnosticData(quickfixes=typo_fix_data),
                     }
                 )
 
@@ -958,7 +1030,7 @@ class Deb822KnownField:
                         "message": obsolete_value_message,
                         "severity": obsolete_severity,
                         "source": "debputy",
-                        "data": obsolete_fix_data,
+                        "data": DiagnosticData(quickfixes=obsolete_fix_data),
                     }
                 )
 
@@ -974,11 +1046,180 @@ class Deb822KnownField:
             )
             yield from (Diagnostic(value_range, **issue_data) for issue_data in issues)
 
+    def reformat_field(
+        self,
+        effective_preference: "EffectivePreference",
+        stanza_range: TERange,
+        kvpair: Deb822KeyValuePairElement,
+        formatter: FormatterCallback,
+        position_codec: LintCapablePositionCodec,
+        lines: List[str],
+    ) -> Iterable[TextEdit]:
+        kvpair_range = kvpair.range_in_parent().relative_to(stanza_range.start_pos)
+        return trim_end_of_line_whitespace(
+            position_codec,
+            lines,
+            line_range=range(
+                kvpair_range.start_pos.line_position,
+                kvpair_range.end_pos.line_position,
+            ),
+        )
+
 
 @dataclasses.dataclass(slots=True, frozen=True)
-class DctrlKnownField(Deb822KnownField):
+class DctrlLikeKnownField(Deb822KnownField):
+
+    def reformat_field(
+        self,
+        effective_preference: "EffectivePreference",
+        stanza_range: TERange,
+        kvpair: Deb822KeyValuePairElement,
+        formatter: FormatterCallback,
+        position_codec: LintCapablePositionCodec,
+        lines: List[str],
+    ) -> Iterable[TextEdit]:
+        interpretation = self.field_value_class.interpreter()
+        if (
+            not effective_preference.formatting_deb822_normalize_field_content
+            or interpretation is None
+        ):
+            yield from super(DctrlLikeKnownField, self).reformat_field(
+                effective_preference,
+                stanza_range,
+                kvpair,
+                formatter,
+                position_codec,
+                lines,
+            )
+            return
+        if not self.reformattable_field:
+            yield from super(DctrlLikeKnownField, self).reformat_field(
+                effective_preference,
+                stanza_range,
+                kvpair,
+                formatter,
+                position_codec,
+                lines,
+            )
+            return
+        seen: Set[str] = set()
+        old_kvpair_range = kvpair.range_in_parent()
+        sort = self.is_sortable_field
+
+        # Avoid the context manager as we do not want to perform the change (it would contaminate future ranges)
+        field_content = kvpair.interpret_as(interpretation)
+        old_value = field_content.convert_to_text(with_field_name=True)
+        for package_ref in field_content.iter_value_references():
+            value = package_ref.value
+            if self.is_relationship_field:
+                new_value = " | ".join(x.strip() for x in value.split("|"))
+            else:
+                new_value = value
+            if not sort or new_value not in seen:
+                if new_value != value:
+                    package_ref.value = new_value
+                seen.add(new_value)
+            else:
+                package_ref.remove()
+            if sort:
+                field_content.sort(key=_sort_packages_key)
+            field_content.value_formatter(formatter)
+            field_content.reformat_when_finished()
+
+        new_value = field_content.convert_to_text(with_field_name=True)
+        if new_value != old_value:
+            range_server_units = te_range_to_lsp(
+                old_kvpair_range.relative_to(stanza_range.start_pos)
+            )
+            yield TextEdit(
+                position_codec.range_to_client_units(lines, range_server_units),
+                new_value,
+            )
+
+    @property
+    def reformattable_field(self) -> bool:
+        return self.is_relationship_field or self.is_sortable_field
+
+    @property
+    def is_relationship_field(self) -> bool:
+        return False
+
+    @property
+    def is_sortable_field(self) -> bool:
+        return self.is_relationship_field
+
+
+@dataclasses.dataclass(slots=True, frozen=True)
+class DTestsCtrlKnownField(DctrlLikeKnownField):
+    @property
+    def is_relationship_field(self) -> bool:
+        return self.name == "Depends"
+
+    @property
+    def is_sortable_field(self) -> bool:
+        return self.is_relationship_field or self.name in (
+            "Features",
+            "Restrictions",
+            "Tests",
+        )
+
+
+@dataclasses.dataclass(slots=True, frozen=True)
+class DctrlKnownField(DctrlLikeKnownField):
     inherits_from_source: bool = False
 
+    def reformat_field(
+        self,
+        effective_preference: "EffectivePreference",
+        stanza_range: TERange,
+        kvpair: Deb822KeyValuePairElement,
+        formatter: FormatterCallback,
+        position_codec: LintCapablePositionCodec,
+        lines: List[str],
+    ) -> Iterable[TextEdit]:
+        if (
+            self.name == "Architecture"
+            and effective_preference.formatting_deb822_normalize_field_content
+        ):
+            interpretation = self.field_value_class.interpreter()
+            assert interpretation is not None
+            archs = list(kvpair.interpret_as(interpretation))
+            # Sort, with wildcard entries (such as linux-any) first:
+            archs = sorted(archs, key=lambda x: ("any" not in x, x))
+            new_value = f"{kvpair.field_name}: {' '.join(archs)}\n"
+            if new_value != kvpair.convert_to_text():
+                kvpair_range = te_range_to_lsp(
+                    kvpair.range_in_parent().relative_to(stanza_range.start_pos)
+                )
+                return [
+                    TextEdit(
+                        position_codec.range_to_client_units(lines, kvpair_range),
+                        new_value,
+                    )
+                ]
+            return tuple()
+
+        return super(DctrlKnownField, self).reformat_field(
+            effective_preference,
+            stanza_range,
+            kvpair,
+            formatter,
+            position_codec,
+            lines,
+        )
+
+    @property
+    def is_relationship_field(self) -> bool:
+        name_lc = self.name.lower()
+        return (
+            name_lc in all_package_relationship_fields()
+            or name_lc in all_source_relationship_fields()
+        )
+
+    @property
+    def reformattable_field(self) -> bool:
+        return self.is_relationship_field or self.name == "Uploaders"
+
 
 SOURCE_FIELDS = _fields(
     DctrlKnownField(
@@ -1216,8 +1457,8 @@ SOURCE_FIELDS = _fields(
         FieldValueClass.SINGLE_VALUE,
         deprecated_with_no_replacement=True,
         default_value="no",
-        known_values=_allowed_values("yes", "no"),
-        synopsis_doc="**Obsolete**: Old ACL mechanism for Debian Managers",
+        known_values=allowed_values("yes", "no"),
+        synopsis_doc="**Obsolete**: Old ACL mechanism for Debian Maintainers",
         hover_text=textwrap.dedent(
             """\
                 Obsolete field
@@ -1355,7 +1596,7 @@ SOURCE_FIELDS = _fields(
         "Rules-Requires-Root",
         FieldValueClass.SPACE_SEPARATED_LIST,
         unknown_value_diagnostic_severity=None,
-        known_values=_allowed_values(
+        known_values=allowed_values(
             Keyword(
                 "no",
                 is_exclusive=True,
@@ -1480,7 +1721,7 @@ SOURCE_FIELDS = _fields(
     DctrlKnownField(
         "XS-Autobuild",
         FieldValueClass.SINGLE_VALUE,
-        known_values=_allowed_values("yes"),
+        known_values=allowed_values("yes"),
         synopsis_doc="Whether this non-free is auto-buildable on buildds",
         hover_text=textwrap.dedent(
             """\
@@ -1492,6 +1733,28 @@ SOURCE_FIELDS = _fields(
         ),
     ),
     DctrlKnownField(
+        "X-Style",
+        FieldValueClass.SINGLE_VALUE,
+        known_values=ALL_PUBLIC_NAMED_STYLES,
+        unknown_value_diagnostic_severity=DiagnosticSeverity.Warning,
+        synopsis_doc="Choose a formatting style",
+        hover_text=textwrap.dedent(
+            """\
+        This field is read by `debputy` to determine how it should format the files in the package.
+
+        In its absence, `debputy` will attempt to determine the formatting style by looking at
+        the maintainers and built-in style preferences.
+
+        This value influences commands such as `debputy reformat` and `debputy lsp server`. When this
+        field is present, it will overrule any built-in style detection that `debputy` would otherwise
+        have applied.
+
+        Note that unknown styles will cause the styling to be disabled (and trigger a `debputy lint`
+        warning).
+        """
+        ),
+    ),
+    DctrlKnownField(
         "Description",
         FieldValueClass.FREE_TEXT_FIELD,
         spellcheck_value=True,
@@ -1555,7 +1818,7 @@ BINARY_FIELDS = _fields(
         "Package-Type",
         FieldValueClass.SINGLE_VALUE,
         default_value="deb",
-        known_values=_allowed_values(
+        known_values=allowed_values(
             Keyword("deb", hover_text="The package will be built as a regular deb."),
             Keyword(
                 "udeb",
@@ -1579,7 +1842,7 @@ BINARY_FIELDS = _fields(
         FieldValueClass.SPACE_SEPARATED_LIST,
         missing_field_severity=DiagnosticSeverity.Error,
         unknown_value_diagnostic_severity=None,
-        known_values=_allowed_values(*dpkg_arch_and_wildcards()),
+        known_values=allowed_values(*dpkg_arch_and_wildcards()),
         synopsis_doc="Architecture of the package",
         hover_text=textwrap.dedent(
             """\
@@ -1614,7 +1877,7 @@ BINARY_FIELDS = _fields(
         "Essential",
         FieldValueClass.SINGLE_VALUE,
         default_value="no",
-        known_values=_allowed_values(
+        known_values=allowed_values(
             Keyword(
                 "yes",
                 hover_text="The package is essential and uninstalling it will completely and utterly break the"
@@ -1661,7 +1924,7 @@ BINARY_FIELDS = _fields(
         replaced_by="Protected",
         default_value="no",
         synopsis_doc="**Deprecated**: Use Protected instead",
-        known_values=_allowed_values(
+        known_values=allowed_values(
             Keyword(
                 "yes",
                 hover_text="The package is protected and attempts to uninstall it will cause strong warnings to the"
@@ -1691,7 +1954,7 @@ BINARY_FIELDS = _fields(
         "Protected",
         FieldValueClass.SINGLE_VALUE,
         default_value="no",
-        known_values=_allowed_values(
+        known_values=allowed_values(
             Keyword(
                 "yes",
                 hover_text="The package is protected and attempts to uninstall it will cause strong warnings to the"
@@ -2066,7 +2329,7 @@ BINARY_FIELDS = _fields(
         warn_if_default=False,
         default_value="no",
         custom_field_check=_dctrl_ma_field_validation,
-        known_values=_allowed_values(
+        known_values=allowed_values(
             Keyword(
                 "no",
                 hover_text=textwrap.dedent(
@@ -2269,7 +2532,7 @@ BINARY_FIELDS = _fields(
         FieldValueClass.SINGLE_VALUE,
         custom_field_check=_arch_not_all_only_field_validation,
         default_value="host",
-        known_values=_allowed_values(
+        known_values=allowed_values(
             Keyword(
                 "host",
                 hover_text="The package should be compiled for `DEB_HOST_TARGET` (the default).",
@@ -2870,11 +3133,11 @@ _DEP5_LICENSE_FIELDS = _fields(
 )
 
 _DTESTSCTRL_FIELDS = _fields(
-    Deb822KnownField(
+    DTestsCtrlKnownField(
         "Architecture",
         FieldValueClass.SPACE_SEPARATED_LIST,
         unknown_value_diagnostic_severity=None,
-        known_values=_allowed_values(*dpkg_arch_and_wildcards()),
+        known_values=allowed_values(*dpkg_arch_and_wildcards()),
         synopsis_doc="Only run these tests on specific architectures",
         hover_text=textwrap.dedent(
             """\
@@ -2890,7 +3153,7 @@ _DTESTSCTRL_FIELDS = _fields(
         """
         ),
     ),
-    Deb822KnownField(
+    DTestsCtrlKnownField(
         "Classes",
         FieldValueClass.FREE_TEXT_FIELD,
         synopsis_doc="Hardware related tagging",
@@ -2912,7 +3175,7 @@ _DTESTSCTRL_FIELDS = _fields(
         """
         ),
     ),
-    Deb822KnownField(
+    DTestsCtrlKnownField(
         "Depends",
         FieldValueClass.COMMA_SEPARATED_LIST,
         default_value="@",
@@ -2952,7 +3215,7 @@ _DTESTSCTRL_FIELDS = _fields(
             the source are installed unless explicitly requested.
         """,
     ),
-    Deb822KnownField(
+    DTestsCtrlKnownField(
         "Features",
         FieldValueClass.COMMA_OR_SPACE_SEPARATED_LIST,
         hover_text=textwrap.dedent(
@@ -2965,11 +3228,11 @@ _DTESTSCTRL_FIELDS = _fields(
         """
         ),
     ),
-    Deb822KnownField(
+    DTestsCtrlKnownField(
         "Restrictions",
         FieldValueClass.COMMA_OR_SPACE_SEPARATED_LIST,
         unknown_value_diagnostic_severity=DiagnosticSeverity.Warning,
-        known_values=_allowed_values(
+        known_values=allowed_values(
             Keyword(
                 "allow-stderr",
                 hover_text=textwrap.dedent(
@@ -3287,7 +3550,7 @@ _DTESTSCTRL_FIELDS = _fields(
         """
         ),
     ),
-    Deb822KnownField(
+    DTestsCtrlKnownField(
         "Tests",
         FieldValueClass.COMMA_OR_SPACE_SEPARATED_LIST,
         synopsis_doc="List of test scripts to run",
@@ -3304,7 +3567,7 @@ _DTESTSCTRL_FIELDS = _fields(
         """
         ),
     ),
-    Deb822KnownField(
+    DTestsCtrlKnownField(
         "Test-Command",
         FieldValueClass.FREE_TEXT_FIELD,
         synopsis_doc="Single test command",
@@ -3323,7 +3586,7 @@ _DTESTSCTRL_FIELDS = _fields(
         """
         ),
     ),
-    Deb822KnownField(
+    DTestsCtrlKnownField(
         "Test-Directory",
         FieldValueClass.FREE_TEXT_FIELD,  # TODO: Single path
         default_value="debian/tests",
@@ -3367,6 +3630,28 @@ class StanzaMetadata(Mapping[str, F], Generic[F], ABC):
     def __iter__(self):
         return iter(self.stanza_fields.keys())
 
+    def reformat_stanza(
+        self,
+        effective_preference: "EffectivePreference",
+        stanza: Deb822ParagraphElement,
+        stanza_range: TERange,
+        formatter: FormatterCallback,
+        position_codec: LintCapablePositionCodec,
+        lines: List[str],
+    ) -> Iterable[TextEdit]:
+        for known_field in self.stanza_fields.values():
+            kvpair = stanza.get_kvpair_element(known_field.name, use_get=True)
+            if kvpair is None:
+                continue
+            yield from known_field.reformat_field(
+                effective_preference,
+                stanza_range,
+                kvpair,
+                formatter,
+                position_codec,
+                lines,
+            )
+
 
 @dataclasses.dataclass(slots=True, frozen=True)
 class Dep5StanzaMetadata(StanzaMetadata[Deb822KnownField]):
@@ -3390,7 +3675,7 @@ class DctrlStanzaMetadata(StanzaMetadata[DctrlKnownField]):
 
 
 @dataclasses.dataclass(slots=True, frozen=True)
-class DTestsCtrlStanzaMetadata(StanzaMetadata[Deb822KnownField]):
+class DTestsCtrlStanzaMetadata(StanzaMetadata[DTestsCtrlKnownField]):
 
     def stanza_diagnostics(
         self,
@@ -3425,6 +3710,40 @@ class Deb822FileMetadata(Generic[S]):
         except KeyError:
             return None
 
+    def reformat(
+        self,
+        effective_preference: "EffectivePreference",
+        deb822_file: Deb822FileElement,
+        formatter: FormatterCallback,
+        _content: str,
+        position_codec: LintCapablePositionCodec,
+        lines: List[str],
+    ) -> Iterable[TextEdit]:
+        stanza_idx = -1
+        for token_or_element in deb822_file.iter_parts():
+            if isinstance(token_or_element, Deb822ParagraphElement):
+                stanza_range = token_or_element.range_in_parent()
+                stanza_idx += 1
+                stanza_metadata = self.classify_stanza(token_or_element, stanza_idx)
+                yield from stanza_metadata.reformat_stanza(
+                    effective_preference,
+                    token_or_element,
+                    stanza_range,
+                    formatter,
+                    position_codec,
+                    lines,
+                )
+            else:
+                token_range = token_or_element.range_in_parent()
+                yield from trim_end_of_line_whitespace(
+                    position_codec,
+                    lines,
+                    line_range=range(
+                        token_range.start_pos.line_position,
+                        token_range.end_pos.line_position,
+                    ),
+                )
+
 
 _DCTRL_SOURCE_STANZA = DctrlStanzaMetadata(
     "Source",
@@ -3503,6 +3822,78 @@ class DctrlFileMetadata(Deb822FileMetadata[DctrlStanzaMetadata]):
             return _DCTRL_PACKAGE_STANZA
         raise KeyError(item)
 
+    def reformat(
+        self,
+        effective_preference: "EffectivePreference",
+        deb822_file: Deb822FileElement,
+        formatter: FormatterCallback,
+        content: str,
+        position_codec: LintCapablePositionCodec,
+        lines: List[str],
+    ) -> Iterable[TextEdit]:
+        edits = list(
+            super().reformat(
+                effective_preference,
+                deb822_file,
+                formatter,
+                content,
+                position_codec,
+                lines,
+            )
+        )
+
+        if (
+            not effective_preference.formatting_deb822_normalize_stanza_order
+            or deb822_file.find_first_error_element() is not None
+        ):
+            return edits
+        names = []
+        for idx, stanza in enumerate(deb822_file):
+            if idx < 2:
+                continue
+            name = stanza.get("Package")
+            if name is None:
+                return edits
+            names.append(name)
+
+        reordered = sorted(names)
+        if names == reordered:
+            return edits
+
+        if edits:
+            content = apply_text_edits(content, lines, edits)
+            lines = content.splitlines(keepends=True)
+            deb822_file = parse_deb822_file(
+                lines,
+                accept_files_with_duplicated_fields=True,
+                accept_files_with_error_tokens=True,
+            )
+
+        stanzas = list(deb822_file)
+        reordered_stanza = stanzas[:2] + sorted(
+            stanzas[2:], key=operator.itemgetter("Package")
+        )
+        bits = []
+        stanza_idx = 0
+        for token_or_element in deb822_file.iter_parts():
+            if isinstance(token_or_element, Deb822ParagraphElement):
+                bits.append(reordered_stanza[stanza_idx].dump())
+                stanza_idx += 1
+            else:
+                bits.append(token_or_element.convert_to_text())
+
+        new_content = "".join(bits)
+
+        return [
+            TextEdit(
+                Range(
+                    Position(0, 0),
+                    Position(len(lines) + 1, 0),
+                ),
+                new_content,
+            )
+        ]
+
 
 class DTestsCtrlFileMetadata(Deb822FileMetadata[DctrlStanzaMetadata]):
     def guess_stanza_classification_by_idx(self, stanza_idx: int) -> S:
diff --git a/src/debputy/lsp/lsp_debian_copyright.py b/src/debputy/lsp/lsp_debian_copyright.py
index b037792..abd5488 100644
--- a/src/debputy/lsp/lsp_debian_copyright.py
+++ b/src/debputy/lsp/lsp_debian_copyright.py
@@ -30,9 +30,13 @@ from lsprotocol.types import (
     SemanticTokensParams,
     FoldingRangeParams,
     FoldingRange,
+    WillSaveTextDocumentParams,
+    TextEdit,
+    DocumentFormattingParams,
 )
 
 from debputy.linting.lint_util import LintState
+from debputy.lsp.diagnostics import DiagnosticData
 from debputy.lsp.lsp_debian_control_reference_data import (
     _DEP5_HEADER_FIELDS,
     _DEP5_FILES_FIELDS,
@@ -47,6 +51,8 @@ from debputy.lsp.lsp_features import (
     lsp_standard_handler,
     lsp_folding_ranges,
     lsp_semantic_tokens_full,
+    lsp_will_save_wait_until,
+    lsp_format_document,
 )
 from debputy.lsp.lsp_generic_deb822 import (
     deb822_completer,
@@ -54,6 +60,7 @@ from debputy.lsp.lsp_generic_deb822 import (
     deb822_folding_ranges,
     deb822_semantic_tokens_full,
     deb822_token_iter,
+    deb822_format_file,
 )
 from debputy.lsp.quickfixes import (
     propose_correct_text_quick_fix,
@@ -103,7 +110,6 @@ _LANGUAGE_IDS = [
 _DEP5_FILE_METADATA = Dep5FileMetadata()
 
 lsp_standard_handler(_LANGUAGE_IDS, TEXT_DOCUMENT_CODE_ACTION)
-lsp_standard_handler(_LANGUAGE_IDS, TEXT_DOCUMENT_WILL_SAVE_WAIT_UNTIL)
 
 
 @lsp_hover(_LANGUAGE_IDS)
@@ -183,7 +189,10 @@ def _diagnostics_for_paragraph(
         normalized_field_name_lc = normalize_dctrl_field_name(field_name_lc)
         known_field = known_fields.get(normalized_field_name_lc)
         field_value = stanza[field_name]
-        field_range_te = kvpair.range_in_parent().relative_to(stanza_position)
+        kvpair_position = kvpair.position_in_parent().relative_to(stanza_position)
+        field_range_te = kvpair.field_token.range_in_parent().relative_to(
+            kvpair_position
+        )
         field_position_te = field_range_te.start_pos
         field_range_server_units = te_range_to_lsp(field_range_te)
         field_range = position_codec.range_to_client_units(
@@ -223,10 +232,12 @@ def _diagnostics_for_paragraph(
                         f'The "{field_name}" looks like a typo of "{known_field.name}".',
                         severity=DiagnosticSeverity.Warning,
                         source="debputy",
-                        data=[
-                            propose_correct_text_quick_fix(known_fields[m].name)
-                            for m in candidates
-                        ],
+                        data=DiagnosticData(
+                            quickfixes=[
+                                propose_correct_text_quick_fix(known_fields[m].name)
+                                for m in candidates
+                            ]
+                        ),
                     )
                 )
         if known_field is None:
@@ -261,6 +272,7 @@ def _diagnostics_for_paragraph(
                 kvpair,
                 stanza,
                 stanza_position,
+                kvpair_position,
                 position_codec,
                 lines,
                 field_name_typo_reported=field_name_typo_detected,
@@ -301,9 +313,12 @@ def _diagnostics_for_paragraph(
                             f'Spelling "{word}"',
                             severity=DiagnosticSeverity.Hint,
                             source="debputy",
-                            data=[
-                                propose_correct_text_quick_fix(c) for c in corrections
-                            ],
+                            data=DiagnosticData(
+                                quickfixes=[
+                                    propose_correct_text_quick_fix(c)
+                                    for c in corrections
+                                ]
+                            ),
                         )
                     )
         if known_field.warn_if_default and field_value == known_field.default_value:
@@ -409,7 +424,11 @@ def _scan_for_syntax_errors_and_token_level_diagnostics(
                         f'Spelling "{word}"',
                         severity=DiagnosticSeverity.Hint,
                         source="debputy",
-                        data=[propose_correct_text_quick_fix(c) for c in corrections],
+                        data=DiagnosticData(
+                            quickfixes=[
+                                propose_correct_text_quick_fix(c) for c in corrections
+                            ]
+                        ),
                     )
                 )
     return first_error
@@ -471,6 +490,32 @@ def _lint_debian_copyright(
     return diagnostics
 
 
+@lsp_will_save_wait_until(_LANGUAGE_IDS)
+def _debian_copyright_on_save_formatting(
+    ls: "DebputyLanguageServer",
+    params: WillSaveTextDocumentParams,
+) -> Optional[Sequence[TextEdit]]:
+    doc = ls.workspace.get_text_document(params.text_document.uri)
+    lint_state = ls.lint_state(doc)
+    return deb822_format_file(lint_state, _DEP5_FILE_METADATA)
+
+
+def _reformat_debian_copyright(
+    lint_state: LintState,
+) -> Optional[Sequence[TextEdit]]:
+    return deb822_format_file(lint_state, _DEP5_FILE_METADATA)
+
+
+@lsp_format_document(_LANGUAGE_IDS)
+def _debian_copyright_on_save_formatting(
+    ls: "DebputyLanguageServer",
+    params: DocumentFormattingParams,
+) -> Optional[Sequence[TextEdit]]:
+    doc = ls.workspace.get_text_document(params.text_document.uri)
+    lint_state = ls.lint_state(doc)
+    return deb822_format_file(lint_state, _DEP5_FILE_METADATA)
+
+
 @lsp_semantic_tokens_full(_LANGUAGE_IDS)
 def _debian_copyright_semantic_tokens_full(
     ls: "DebputyLanguageServer",
diff --git a/src/debputy/lsp/lsp_debian_debputy_manifest.py b/src/debputy/lsp/lsp_debian_debputy_manifest.py
index 74b5d7b..e75534b 100644
--- a/src/debputy/lsp/lsp_debian_debputy_manifest.py
+++ b/src/debputy/lsp/lsp_debian_debputy_manifest.py
@@ -30,6 +30,7 @@ from lsprotocol.types import (
 )
 
 from debputy.linting.lint_util import LintState
+from debputy.lsp.diagnostics import DiagnosticData
 from debputy.lsp.quickfixes import propose_correct_text_quick_fix
 from debputy.manifest_parser.base_types import DebputyDispatchableType
 from debputy.plugin.api.feature_set import PluginProvidedFeatureSet
@@ -227,7 +228,9 @@ def _unknown_key(
         message_format.format(key=key) + extra,
         DiagnosticSeverity.Error,
         source="debputy",
-        data=[propose_correct_text_quick_fix(n) for n in candidates],
+        data=DiagnosticData(
+            quickfixes=[propose_correct_text_quick_fix(n) for n in candidates]
+        ),
     )
     return diagnostic, corrected_key
 
diff --git a/src/debputy/lsp/lsp_debian_rules.py b/src/debputy/lsp/lsp_debian_rules.py
index 7f5aef9..ec8d9d6 100644
--- a/src/debputy/lsp/lsp_debian_rules.py
+++ b/src/debputy/lsp/lsp_debian_rules.py
@@ -29,6 +29,7 @@ from lsprotocol.types import (
 
 from debputy.debhelper_emulation import parse_drules_for_addons
 from debputy.linting.lint_util import LintState
+from debputy.lsp.diagnostics import DiagnosticData
 from debputy.lsp.lsp_features import (
     lint_diagnostics,
     lsp_standard_handler,
@@ -309,7 +310,7 @@ def _lint_debian_rules_impl(
                 r,
                 msg,
                 severity=DiagnosticSeverity.Warning,
-                data=fixes,
+                data=DiagnosticData(quickfixes=fixes),
                 source=source,
             )
         )
diff --git a/src/debputy/lsp/lsp_debian_tests_control.py b/src/debputy/lsp/lsp_debian_tests_control.py
index cc27579..001dbe2 100644
--- a/src/debputy/lsp/lsp_debian_tests_control.py
+++ b/src/debputy/lsp/lsp_debian_tests_control.py
@@ -3,16 +3,12 @@ from typing import (
     Union,
     Sequence,
     Tuple,
-    Iterator,
     Optional,
-    Iterable,
     Mapping,
     List,
-    Set,
     Dict,
 )
 
-from debputy.lsp.debputy_ls import DebputyLanguageServer
 from lsprotocol.types import (
     DiagnosticSeverity,
     Range,
@@ -21,7 +17,6 @@ from lsprotocol.types import (
     CompletionItem,
     CompletionList,
     CompletionParams,
-    TEXT_DOCUMENT_WILL_SAVE_WAIT_UNTIL,
     DiagnosticRelatedInformation,
     Location,
     HoverParams,
@@ -31,9 +26,14 @@ from lsprotocol.types import (
     SemanticTokensParams,
     FoldingRangeParams,
     FoldingRange,
+    WillSaveTextDocumentParams,
+    TextEdit,
+    DocumentFormattingParams,
 )
 
 from debputy.linting.lint_util import LintState
+from debputy.lsp.debputy_ls import DebputyLanguageServer
+from debputy.lsp.diagnostics import DiagnosticData
 from debputy.lsp.lsp_debian_control_reference_data import (
     Deb822KnownField,
     DTestsCtrlFileMetadata,
@@ -46,6 +46,8 @@ from debputy.lsp.lsp_features import (
     lsp_standard_handler,
     lsp_folding_ranges,
     lsp_semantic_tokens_full,
+    lsp_will_save_wait_until,
+    lsp_format_document,
 )
 from debputy.lsp.lsp_generic_deb822 import (
     deb822_completer,
@@ -53,6 +55,7 @@ from debputy.lsp.lsp_generic_deb822 import (
     deb822_folding_ranges,
     deb822_semantic_tokens_full,
     deb822_token_iter,
+    deb822_format_file,
 )
 from debputy.lsp.quickfixes import (
     propose_correct_text_quick_fix,
@@ -73,9 +76,6 @@ from debputy.lsp.vendoring._deb822_repro.parsing import (
     Deb822KeyValuePairElement,
     LIST_SPACE_SEPARATED_INTERPRETATION,
 )
-from debputy.lsp.vendoring._deb822_repro.tokens import (
-    Deb822Token,
-)
 
 try:
     from debputy.lsp.vendoring._deb822_repro.locatable import (
@@ -99,10 +99,9 @@ _LANGUAGE_IDS = [
     "debtestscontrol",
 ]
 
-_DEP5_FILE_METADATA = DTestsCtrlFileMetadata()
+_DTESTS_CTRL_FILE_METADATA = DTestsCtrlFileMetadata()
 
 lsp_standard_handler(_LANGUAGE_IDS, TEXT_DOCUMENT_CODE_ACTION)
-lsp_standard_handler(_LANGUAGE_IDS, TEXT_DOCUMENT_WILL_SAVE_WAIT_UNTIL)
 
 
 @lsp_hover(_LANGUAGE_IDS)
@@ -110,7 +109,7 @@ def debian_tests_control_hover(
     ls: "DebputyLanguageServer",
     params: HoverParams,
 ) -> Optional[Hover]:
-    return deb822_hover(ls, params, _DEP5_FILE_METADATA)
+    return deb822_hover(ls, params, _DTESTS_CTRL_FILE_METADATA)
 
 
 @lsp_completer(_LANGUAGE_IDS)
@@ -118,7 +117,7 @@ def debian_tests_control_completions(
     ls: "DebputyLanguageServer",
     params: CompletionParams,
 ) -> Optional[Union[CompletionList, Sequence[CompletionItem]]]:
-    return deb822_completer(ls, params, _DEP5_FILE_METADATA)
+    return deb822_completer(ls, params, _DTESTS_CTRL_FILE_METADATA)
 
 
 @lsp_folding_ranges(_LANGUAGE_IDS)
@@ -126,7 +125,7 @@ def debian_tests_control_folding_ranges(
     ls: "DebputyLanguageServer",
     params: FoldingRangeParams,
 ) -> Optional[Sequence[FoldingRange]]:
-    return deb822_folding_ranges(ls, params, _DEP5_FILE_METADATA)
+    return deb822_folding_ranges(ls, params, _DTESTS_CTRL_FILE_METADATA)
 
 
 def _paragraph_representation_field(
@@ -175,7 +174,7 @@ def _diagnostics_for_paragraph(
         diagnostics.append(
             Diagnostic(
                 representation_field_range,
-                f'Stanza must have either a "Tests" or a "Test-Command" field',
+                'Stanza must have either a "Tests" or a "Test-Command" field',
                 severity=DiagnosticSeverity.Error,
                 source="debputy",
             )
@@ -199,7 +198,10 @@ def _diagnostics_for_paragraph(
         normalized_field_name_lc = normalize_dctrl_field_name(field_name_lc)
         known_field = known_fields.get(normalized_field_name_lc)
         field_value = stanza[field_name]
-        field_range_te = kvpair.range_in_parent().relative_to(stanza_position)
+        kvpair_position = kvpair.position_in_parent().relative_to(stanza_position)
+        field_range_te = kvpair.field_token.range_in_parent().relative_to(
+            kvpair_position
+        )
         field_position_te = field_range_te.start_pos
         field_range_server_units = te_range_to_lsp(field_range_te)
         field_range = position_codec.range_to_client_units(
@@ -239,10 +241,12 @@ def _diagnostics_for_paragraph(
                         f'The "{field_name}" looks like a typo of "{known_field.name}".',
                         severity=DiagnosticSeverity.Warning,
                         source="debputy",
-                        data=[
-                            propose_correct_text_quick_fix(known_fields[m].name)
-                            for m in candidates
-                        ],
+                        data=DiagnosticData(
+                            quickfixes=[
+                                propose_correct_text_quick_fix(known_fields[m].name)
+                                for m in candidates
+                            ]
+                        ),
                     )
                 )
         if field_value.strip() == "":
@@ -260,6 +264,7 @@ def _diagnostics_for_paragraph(
                 kvpair,
                 stanza,
                 stanza_position,
+                kvpair_position,
                 position_codec,
                 lines,
                 field_name_typo_reported=field_name_typo_detected,
@@ -300,9 +305,12 @@ def _diagnostics_for_paragraph(
                             f'Spelling "{word}"',
                             severity=DiagnosticSeverity.Hint,
                             source="debputy",
-                            data=[
-                                propose_correct_text_quick_fix(c) for c in corrections
-                            ],
+                            data=DiagnosticData(
+                                quickfixes=[
+                                    propose_correct_text_quick_fix(c)
+                                    for c in corrections
+                                ]
+                            ),
                         )
                     )
         if known_field.warn_if_default and field_value == known_field.default_value:
@@ -407,7 +415,11 @@ def _scan_for_syntax_errors_and_token_level_diagnostics(
                         f'Spelling "{word}"',
                         severity=DiagnosticSeverity.Hint,
                         source="debputy",
-                        data=[propose_correct_text_quick_fix(c) for c in corrections],
+                        data=DiagnosticData(
+                            quickfixes=[
+                                propose_correct_text_quick_fix(c) for c in corrections
+                            ]
+                        ),
                     )
                 )
     return first_error
@@ -453,6 +465,32 @@ def _lint_debian_tests_control(
     return diagnostics
 
 
+@lsp_will_save_wait_until(_LANGUAGE_IDS)
+def _debian_tests_control_on_save_formatting(
+    ls: "DebputyLanguageServer",
+    params: WillSaveTextDocumentParams,
+) -> Optional[Sequence[TextEdit]]:
+    doc = ls.workspace.get_text_document(params.text_document.uri)
+    lint_state = ls.lint_state(doc)
+    return deb822_format_file(lint_state, _DTESTS_CTRL_FILE_METADATA)
+
+
+def _reformat_debian_tests_control(
+    lint_state: LintState,
+) -> Optional[Sequence[TextEdit]]:
+    return deb822_format_file(lint_state, _DTESTS_CTRL_FILE_METADATA)
+
+
+@lsp_format_document(_LANGUAGE_IDS)
+def _debian_tests_control_on_save_formatting(
+    ls: "DebputyLanguageServer",
+    params: DocumentFormattingParams,
+) -> Optional[Sequence[TextEdit]]:
+    doc = ls.workspace.get_text_document(params.text_document.uri)
+    lint_state = ls.lint_state(doc)
+    return deb822_format_file(lint_state, _DTESTS_CTRL_FILE_METADATA)
+
+
 @lsp_semantic_tokens_full(_LANGUAGE_IDS)
 def _debian_tests_control_semantic_tokens_full(
     ls: "DebputyLanguageServer",
@@ -461,5 +499,5 @@ def _debian_tests_control_semantic_tokens_full(
     return deb822_semantic_tokens_full(
         ls,
         request,
-        _DEP5_FILE_METADATA,
+        _DTESTS_CTRL_FILE_METADATA,
     )
diff --git a/src/debputy/lsp/lsp_dispatch.py b/src/debputy/lsp/lsp_dispatch.py
index 5d09a44..99479dc 100644
--- a/src/debputy/lsp/lsp_dispatch.py
+++ b/src/debputy/lsp/lsp_dispatch.py
@@ -1,5 +1,4 @@
 import asyncio
-import os.path
 from typing import (
     Dict,
     Sequence,
@@ -9,8 +8,6 @@ from typing import (
     Callable,
     Mapping,
     List,
-    Tuple,
-    Literal,
 )
 
 from lsprotocol.types import (
@@ -35,6 +32,10 @@ from lsprotocol.types import (
     CodeAction,
     CodeActionParams,
     SemanticTokensRegistrationOptions,
+    TextEdit,
+    TEXT_DOCUMENT_WILL_SAVE_WAIT_UNTIL,
+    WillSaveTextDocumentParams,
+    TEXT_DOCUMENT_FORMATTING,
 )
 
 from debputy import __version__
@@ -45,6 +46,8 @@ from debputy.lsp.lsp_features import (
     SEMANTIC_TOKENS_FULL_HANDLERS,
     CODE_ACTION_HANDLERS,
     SEMANTIC_TOKENS_LEGEND,
+    WILL_SAVE_WAIT_UNTIL_HANDLERS,
+    FORMAT_FILE_HANDLERS,
 )
 from debputy.util import _info
 
@@ -86,8 +89,8 @@ async def _open_document(
 
 @DEBPUTY_LANGUAGE_SERVER.feature(TEXT_DOCUMENT_DID_CHANGE)
 async def _changed_document(
-        ls: "DebputyLanguageServer",
-        params: DidChangeTextDocumentParams,
+    ls: "DebputyLanguageServer",
+    params: DidChangeTextDocumentParams,
 ) -> None:
     await _open_or_changed_document(ls, params)
 
@@ -207,6 +210,34 @@ def _semantic_tokens_full(
     )
 
 
+@DEBPUTY_LANGUAGE_SERVER.feature(TEXT_DOCUMENT_WILL_SAVE_WAIT_UNTIL)
+def _will_save_wait_until(
+    ls: "DebputyLanguageServer",
+    params: WillSaveTextDocumentParams,
+) -> Optional[Sequence[TextEdit]]:
+    return _dispatch_standard_handler(
+        ls,
+        params.text_document.uri,
+        params,
+        WILL_SAVE_WAIT_UNTIL_HANDLERS,
+        "On-save formatting",
+    )
+
+
+@DEBPUTY_LANGUAGE_SERVER.feature(TEXT_DOCUMENT_FORMATTING)
+def _will_save_wait_until(
+    ls: "DebputyLanguageServer",
+    params: WillSaveTextDocumentParams,
+) -> Optional[Sequence[TextEdit]]:
+    return _dispatch_standard_handler(
+        ls,
+        params.text_document.uri,
+        params,
+        FORMAT_FILE_HANDLERS,
+        "Full document formatting",
+    )
+
+
 def _dispatch_standard_handler(
     ls: "DebputyLanguageServer",
     doc_uri: str,
diff --git a/src/debputy/lsp/lsp_features.py b/src/debputy/lsp/lsp_features.py
index e7b4445..63e4cd2 100644
--- a/src/debputy/lsp/lsp_features.py
+++ b/src/debputy/lsp/lsp_features.py
@@ -19,6 +19,7 @@ from lsprotocol.types import (
     Diagnostic,
     DidOpenTextDocumentParams,
     SemanticTokensLegend,
+    TEXT_DOCUMENT_FORMATTING,
 )
 
 from debputy.commands.debputy_cmd.context import CommandContext
@@ -61,9 +62,14 @@ CODE_ACTION_HANDLERS = {}
 FOLDING_RANGE_HANDLERS = {}
 SEMANTIC_TOKENS_FULL_HANDLERS = {}
 WILL_SAVE_WAIT_UNTIL_HANDLERS = {}
+FORMAT_FILE_HANDLERS = {}
 _ALIAS_OF = {}
 
 _STANDARD_HANDLERS = {
+    TEXT_DOCUMENT_FORMATTING: (
+        FORMAT_FILE_HANDLERS,
+        on_save_trim_end_of_line_whitespace,
+    ),
     TEXT_DOCUMENT_CODE_ACTION: (
         CODE_ACTION_HANDLERS,
         lambda ls, params: provide_standard_quickfixes_from_diagnostics(params),
@@ -145,6 +151,16 @@ def lsp_folding_ranges(file_formats: Union[str, Sequence[str]]) -> Callable[[C],
     return _registering_wrapper(file_formats, FOLDING_RANGE_HANDLERS)
 
 
+def lsp_will_save_wait_until(
+    file_formats: Union[str, Sequence[str]]
+) -> Callable[[C], C]:
+    return _registering_wrapper(file_formats, WILL_SAVE_WAIT_UNTIL_HANDLERS)
+
+
+def lsp_format_document(file_formats: Union[str, Sequence[str]]) -> Callable[[C], C]:
+    return _registering_wrapper(file_formats, FORMAT_FILE_HANDLERS)
+
+
 def lsp_semantic_tokens_full(
     file_formats: Union[str, Sequence[str]]
 ) -> Callable[[C], C]:
@@ -214,6 +230,7 @@ def describe_lsp_features(context: CommandContext) -> None:
         ("folding ranges", FOLDING_RANGE_HANDLERS),
         ("semantic tokens", SEMANTIC_TOKENS_FULL_HANDLERS),
         ("on-save handler", WILL_SAVE_WAIT_UNTIL_HANDLERS),
+        ("format file handler", FORMAT_FILE_HANDLERS),
     ]
     print("LSP language IDs and their features:")
     all_ids = sorted(set(lid for _, t in feature_list for lid in t))
diff --git a/src/debputy/lsp/lsp_generic_deb822.py b/src/debputy/lsp/lsp_generic_deb822.py
index e2124e4..409b27e 100644
--- a/src/debputy/lsp/lsp_generic_deb822.py
+++ b/src/debputy/lsp/lsp_generic_deb822.py
@@ -14,26 +14,6 @@ from typing import (
     Callable,
 )
 
-from debputy.lsp.debputy_ls import DebputyLanguageServer
-from debputy.lsp.lsp_debian_control_reference_data import (
-    Deb822FileMetadata,
-    Deb822KnownField,
-    StanzaMetadata,
-    FieldValueClass,
-    F,
-    S,
-)
-from debputy.lsp.lsp_features import SEMANTIC_TOKEN_TYPES_IDS
-from debputy.lsp.text_util import normalize_dctrl_field_name, te_position_to_lsp
-from debputy.lsp.vendoring._deb822_repro import parse_deb822_file
-from debputy.lsp.vendoring._deb822_repro.parsing import (
-    Deb822KeyValuePairElement,
-    LIST_SPACE_SEPARATED_INTERPRETATION,
-    Deb822ParagraphElement,
-    Deb822ValueLineElement,
-)
-from debputy.lsp.vendoring._deb822_repro.tokens import tokenize_deb822_file, Deb822Token
-from debputy.util import _info
 from lsprotocol.types import (
     CompletionParams,
     CompletionList,
@@ -49,7 +29,33 @@ from lsprotocol.types import (
     FoldingRangeKind,
     SemanticTokensParams,
     SemanticTokens,
+    WillSaveTextDocumentParams,
+    TextEdit,
+    DocumentFormattingParams,
+)
+
+from debputy.linting.lint_util import LintState
+from debputy.lsp.debputy_ls import DebputyLanguageServer
+from debputy.lsp.lsp_debian_control_reference_data import (
+    Deb822FileMetadata,
+    Deb822KnownField,
+    StanzaMetadata,
+    F,
+    S,
+)
+from debputy.lsp.lsp_features import SEMANTIC_TOKEN_TYPES_IDS
+from debputy.lsp.text_util import (
+    normalize_dctrl_field_name,
+    te_position_to_lsp,
+    trim_end_of_line_whitespace,
+)
+from debputy.lsp.vendoring._deb822_repro import parse_deb822_file
+from debputy.lsp.vendoring._deb822_repro.parsing import (
+    Deb822KeyValuePairElement,
+    Deb822ParagraphElement,
 )
+from debputy.lsp.vendoring._deb822_repro.tokens import tokenize_deb822_file, Deb822Token
+from debputy.util import _info
 
 try:
     from pygls.server import LanguageServer
@@ -345,7 +351,10 @@ def _deb822_paragraph_semantic_tokens_full(
         stanza_idx=stanza_idx,
     )
     for kvpair in stanza.iter_parts_of_type(Deb822KeyValuePairElement):
-        field_start = kvpair.key_position_in_stanza().relative_to(stanza_position)
+        kvpair_position = kvpair.position_in_parent().relative_to(stanza_position)
+        field_start = kvpair.field_token.position_in_parent().relative_to(
+            kvpair_position
+        )
         comment = kvpair.comment_element
         if comment:
             comment_start_line = field_start.line_position - len(comment)
@@ -378,8 +387,8 @@ def _deb822_paragraph_semantic_tokens_full(
             known_values = frozenset()
             interpretation = None
 
-        value_element_pos = kvpair.value_position_in_stanza().relative_to(
-            stanza_position
+        value_element_pos = kvpair.value_element.position_in_parent().relative_to(
+            kvpair_position
         )
         if interpretation is None:
             # TODO: Emit tokens for value comments of unknown fields.
@@ -410,6 +419,32 @@ def _deb822_paragraph_semantic_tokens_full(
             )
 
 
+def deb822_format_file(
+    lint_state: LintState,
+    file_metadata: Deb822FileMetadata[Any],
+) -> Optional[Sequence[TextEdit]]:
+    effective_preference = lint_state.effective_preference
+    if effective_preference is None:
+        return trim_end_of_line_whitespace(lint_state.position_codec, lint_state.lines)
+    formatter = effective_preference.deb822_formatter()
+    lines = lint_state.lines
+    deb822_file = parse_deb822_file(
+        lines,
+        accept_files_with_duplicated_fields=True,
+        accept_files_with_error_tokens=True,
+    )
+    return list(
+        file_metadata.reformat(
+            effective_preference,
+            deb822_file,
+            formatter,
+            lint_state.content,
+            lint_state.position_codec,
+            lines,
+        )
+    )
+
+
 def deb822_semantic_tokens_full(
     ls: "DebputyLanguageServer",
     request: SemanticTokensParams,
diff --git a/src/debputy/lsp/lsp_reference_keyword.py b/src/debputy/lsp/lsp_reference_keyword.py
new file mode 100644
index 0000000..44f43fd
--- /dev/null
+++ b/src/debputy/lsp/lsp_reference_keyword.py
@@ -0,0 +1,45 @@
+import dataclasses
+import textwrap
+from typing import Optional, Union, Mapping
+
+
+@dataclasses.dataclass(slots=True, frozen=True)
+class Keyword:
+    value: str
+    hover_text: Optional[str] = None
+    is_obsolete: bool = False
+    replaced_by: Optional[str] = None
+    is_exclusive: bool = False
+    """For keywords in fields that allow multiple keywords, the `is_exclusive` can be
+    used for keywords that cannot be used with other keywords. As an example, the `all`
+    value in `Architecture` of `debian/control` cannot be used with any other architecture.
+    """
+
+
+def allowed_values(*values: Union[str, Keyword]) -> Mapping[str, Keyword]:
+    as_keywords = [k if isinstance(k, Keyword) else Keyword(k) for k in values]
+    as_mapping = {k.value: k for k in as_keywords if k.value}
+    # Simple bug check
+    assert len(as_keywords) == len(as_mapping)
+    return as_mapping
+
+
+# This is the set of styles that `debputy` explicitly supports, which is more narrow than
+# the ones in the config file.
+ALL_PUBLIC_NAMED_STYLES = allowed_values(
+    Keyword(
+        "black",
+        hover_text=textwrap.dedent(
+            """\
+            Uncompromising file formatting of Debian packaging files
+
+            By using it, you  agree to cede control over minutiae of hand-formatting. In
+            return, the formatter gives you speed, determinism, and freedom from style
+            discussions about formatting.
+
+            The `black` style is inspired by the `black` Python code formatter. Like with
+            `black`, the style will evolve over time.
+    """
+        ),
+    ),
+)
diff --git a/src/debputy/lsp/quickfixes.py b/src/debputy/lsp/quickfixes.py
index 2d564f4..7a8a904 100644
--- a/src/debputy/lsp/quickfixes.py
+++ b/src/debputy/lsp/quickfixes.py
@@ -26,6 +26,7 @@ from lsprotocol.types import (
     CodeActionKind,
 )
 
+from debputy.lsp.diagnostics import DiagnosticData
 from debputy.util import _warn
 
 try:
@@ -234,10 +235,13 @@ def provide_standard_quickfixes_from_diagnostics(
 ) -> Optional[List[Union[Command, CodeAction]]]:
     actions: List[Union[Command, CodeAction]] = []
     for diagnostic in code_action_params.context.diagnostics:
-        data = diagnostic.data
-        if not isinstance(data, list):
-            data = [data]
-        for action_suggestion in data:
+        if not isinstance(diagnostic.data, dict):
+            continue
+        data: DiagnosticData = cast("DiagnosticData", diagnostic.data)
+        quickfixes = data.get("quickfixes")
+        if quickfixes is None:
+            continue
+        for action_suggestion in quickfixes:
             if (
                 action_suggestion
                 and isinstance(action_suggestion, Mapping)
diff --git a/src/debputy/lsp/spellchecking.py b/src/debputy/lsp/spellchecking.py
index f9027af..b767802 100644
--- a/src/debputy/lsp/spellchecking.py
+++ b/src/debputy/lsp/spellchecking.py
@@ -8,6 +8,7 @@ from typing import Iterable, FrozenSet, Tuple, Optional, List
 from debian.debian_support import Release
 from lsprotocol.types import Diagnostic, Range, Position, DiagnosticSeverity
 
+from debputy.lsp.diagnostics import DiagnosticData
 from debputy.lsp.quickfixes import propose_correct_text_quick_fix
 from debputy.lsp.text_util import LintCapablePositionCodec
 from debputy.util import _info, _warn
@@ -158,7 +159,9 @@ def spellcheck_line(
             f'Spelling "{word}"',
             severity=DiagnosticSeverity.Hint,
             source="debputy",
-            data=[propose_correct_text_quick_fix(c) for c in corrections],
+            data=DiagnosticData(
+                quickfixes=[propose_correct_text_quick_fix(c) for c in corrections]
+            ),
         )
 
 
diff --git a/src/debputy/lsp/style-preferences.yaml b/src/debputy/lsp/style-preferences.yaml
new file mode 100644
index 0000000..6e76d2a
--- /dev/null
+++ b/src/debputy/lsp/style-preferences.yaml
@@ -0,0 +1,67 @@
+formatting:
+  # Like Python's `black`; enforce a style and let me focus on more important matters
+  # Based on the numbers in #895570.
+  #
+  # Note that like Python's `black`, this is a moving target and it will evolve over time.
+  black:
+    deb822:
+      short-indent: true
+      always-wrap: true
+      trailing-separator: true
+      normalize-field-content: true
+      max-line-length: 79
+      normalize-stanza-order: true
+      # Not yet implemented:
+      #  normalize-field-order: true
+
+maintainer-rules:
+
+  niels@thykier.net:
+    canonical-name: Niels Thykier
+    formatting: black
+
+  zeha@debian.org:
+    canonical-name: Chris Hofstaedtler
+    formatting: black
+
+  elbrus@debian.org:
+    canonical-name: Paul Gevers
+    formatting: black
+
+  packages@qa.debian.org:
+    canonical-name: Debian QA Group
+    is-packaging-team: true  # ish; it is for `debputy` definition
+
+
+  # Add ad-hoc single package maintainer teams below here (like foo@packages.debian.org)
+  #
+  # For these avoid setting "canonical-name": Since the maintainer is only used in one
+  # package, there is no value gain in debputy trying to remind other people how it's name
+  # is spelled (instead, it would just make `debputy` annoying if the name is ever changed)
+  #
+  # Note this should ideally just use `X-Style: black` if they use a style that can be
+  # put in `X-Style: black`.
+
+  util-linux@packages.debian.org:
+    # Omitting canonical name for single use ad-hoc team maintainer name
+    formatting: black
+    is-packaging-team: true
+
+  wtmpdb@packages.debian.org:
+    # Omitting canonical name for single use ad-hoc team maintainer name
+    formatting: black
+    is-packaging-team: true
+
+  pdns@packages.debian.org:
+    # Omitting canonical name for single use ad-hoc team maintainer name
+    formatting: black
+    is-packaging-team: true
+
+  pdns-recursor@packages.debian.org:
+    # Omitting canonical name for single use ad-hoc team maintainer name
+    formatting: black
+    is-packaging-team: true
+
+  dnsdist@packages.debian.org:
+    # Omitting canonical name for single use ad-hoc team maintainer name
+    formatting: black
diff --git a/src/debputy/lsp/style_prefs.py b/src/debputy/lsp/style_prefs.py
new file mode 100644
index 0000000..5dfdac2
--- /dev/null
+++ b/src/debputy/lsp/style_prefs.py
@@ -0,0 +1,582 @@
+import dataclasses
+import functools
+import os.path
+import re
+import textwrap
+from typing import (
+    Type,
+    TypeVar,
+    Generic,
+    Optional,
+    List,
+    Union,
+    Callable,
+    Mapping,
+    Self,
+    Dict,
+)
+
+from debputy.lsp.lsp_reference_keyword import ALL_PUBLIC_NAMED_STYLES
+from debputy.lsp.vendoring._deb822_repro.types import FormatterCallback
+from debputy.lsp.vendoring.wrap_and_sort import wrap_and_sort_formatter
+from debputy.packages import SourcePackage
+from debputy.util import _error
+from debputy.yaml import MANIFEST_YAML
+from debputy.yaml.compat import CommentedMap
+
+PT = TypeVar("PT", bool, str, int)
+
+
+BUILTIN_STYLES = os.path.join(os.path.dirname(__file__), "style-preferences.yaml")
+
+_NORMALISE_FIELD_CONTENT_KEY = ["formatting", "deb822", "normalize-field-content"]
+_UPLOADER_SPLIT_RE = re.compile(r"(?<=>)\s*,")
+
+
+@dataclasses.dataclass(slots=True, frozen=True, kw_only=True)
+class PreferenceOption(Generic[PT]):
+    key: Union[str, List[str]]
+    expected_type: Type[PT]
+    description: str
+    default_value: Optional[Union[PT, Callable[[CommentedMap], Optional[PT]]]] = None
+
+    @property
+    def name(self) -> str:
+        if isinstance(self.key, str):
+            return self.key
+        return ".".join(self.key)
+
+    @property
+    def attribute_name(self) -> str:
+        return self.name.replace("-", "_").replace(".", "_")
+
+    def extract_value(
+        self,
+        filename: str,
+        key: str,
+        data: CommentedMap,
+    ) -> Optional[PT]:
+        v = data.mlget(self.key, list_ok=True)
+        if v is None:
+            default_value = self.default_value
+            if callable(default_value):
+                return default_value(data)
+            return default_value
+        if isinstance(v, self.expected_type):
+            return v
+        raise ValueError(
+            f'The value "{self.name}" for key {key} in file "{filename}" should have been a'
+            f" {self.expected_type} but it was not"
+        )
+
+
+def _is_packaging_team_default(m: CommentedMap) -> bool:
+    v = m.get("canonical-name")
+    if not isinstance(v, str):
+        return False
+    v = v.lower()
+    return v.endswith((" maintainer", " maintainers", " team"))
+
+
+def _false_when_formatting_content(m: CommentedMap) -> Optional[bool]:
+    return m.mlget(_NORMALISE_FIELD_CONTENT_KEY, list_ok=True, default=False) is True
+
+
+OPTIONS: List[PreferenceOption] = [
+    PreferenceOption(
+        key="canonical-name",
+        expected_type=str,
+        description=textwrap.dedent(
+            """\
+        Canonical spelling/case of the maintainer name.
+
+        The `debputy` linter will emit a diagnostic if the name is not spelled exactly as provided here.
+        Can be useful to ensure your name is updated after a change of name.
+        """
+        ),
+    ),
+    PreferenceOption(
+        key="is-packaging-team",
+        expected_type=bool,
+        default_value=_is_packaging_team_default,
+        description=textwrap.dedent(
+            """\
+    Whether this entry is for a packaging team
+
+    This affects how styles are applied when multiple maintainers (`Maintainer` + `Uploaders`) are listed
+    in `debian/control`. For package teams, the team preference prevails when the team is in the `Maintainer`
+    field. For non-packaging teams, generally the rules do not apply as soon as there are co-maintainers.
+
+    The default is derived from the canonical name. If said name ends with phrases like "Team" or "Maintainer"
+    then the email is assumed to be for a team by default.
+    """
+        ),
+    ),
+    PreferenceOption(
+        key=["formatting", "deb822", "short-indent"],
+        expected_type=bool,
+        description=textwrap.dedent(
+            """\
+    Whether to use "short" indents for relationship fields (such as `Depends`).
+
+    This roughly corresponds to `wrap-and-sort`'s `-s` option.
+
+    **Example**:
+
+    When `true`, the following:
+    ```
+    Depends: foo,
+             bar
+    ```
+
+    would be reformatted as:
+
+    ```
+    Depends:
+     foo,
+     bar
+    ```
+
+    (Assuming `formatting.deb822.short-indent` is `false`)
+
+    Note that defaults to `false` *if* (and only if) other formatting options will trigger reformat of
+    the field and this option has not been set. Setting this option can trigger reformatting of fields
+    that span multiple lines.
+
+    Additionally, this only triggers when a field is being reformatted. Generally that requires
+    another option such as `formatting.deb822.normalize-field-content` for that to happen.
+    """
+        ),
+    ),
+    PreferenceOption(
+        key=["formatting", "deb822", "always-wrap"],
+        expected_type=bool,
+        description=textwrap.dedent(
+            """\
+    Whether to always wrap fields (such as `Depends`).
+
+    This roughly corresponds to `wrap-and-sort`'s `-a` option.
+
+    **Example**:
+
+    When `true`, the following:
+    ```
+    Depends: foo, bar
+    ```
+
+    would be reformatted as:
+
+    ```
+    Depends: foo,
+             bar
+    ```
+
+    (Assuming `formatting.deb822.short-indent` is `false`)
+
+    This option only applies to fields where formatting is a pure style preference. As an
+    example, `Description` (`debian/control`) or `License` (`debian/copyright`) will not
+    be affected by this option.
+
+    Note: When `true`, this option overrules `formatting.deb822.max-line-length` when they interact. 
+    Additionally, this only triggers when a field is being reformatted. Generally that requires
+    another option such as `formatting.deb822.normalize-field-content` for that to happen.
+    """
+        ),
+    ),
+    PreferenceOption(
+        key=["formatting", "deb822", "trailing-separator"],
+        expected_type=bool,
+        default_value=False,
+        description=textwrap.dedent(
+            """\
+    Whether to always end relationship fields (such as `Depends`) with a trailing separator.
+
+    This roughly corresponds to `wrap-and-sort`'s `-t` option.
+
+    **Example**:
+
+    When `true`, the following:
+    ```
+    Depends: foo,
+             bar
+    ```
+
+    would be reformatted as:
+
+    ```
+    Depends: foo,
+             bar,
+    ```
+
+    Note: The trailing separator is only applied if the field is reformatted. This means this option
+    generally requires another option to trigger reformatting (like
+    `formatting.deb822.normalize-field-content`).
+    """
+        ),
+    ),
+    PreferenceOption(
+        key=["formatting", "deb822", "max-line-length"],
+        expected_type=int,
+        default_value=79,
+        description=textwrap.dedent(
+            """\
+    How long a value line can be before it should be line wrapped.
+
+    This roughly corresponds to `wrap-and-sort`'s `--max-line-length` option.
+
+    This option only applies to fields where formatting is a pure style preference. As an
+    example, `Description` (`debian/control`) or `License` (`debian/copyright`) will not
+    be affected by this option.
+
+    Note: When `formatting.deb822.always-wrap` is `true`, then this option will be overruled.
+    Additionally, this only triggers when a field is being reformatted. Generally that requires
+    another option such as `formatting.deb822.normalize-field-content` for that to happen.
+    """
+        ),
+    ),
+    PreferenceOption(
+        key=_NORMALISE_FIELD_CONTENT_KEY,
+        expected_type=bool,
+        default_value=False,
+        description=textwrap.dedent(
+            """\
+    Whether to normalize field content.
+
+    This roughly corresponds to the subset of `wrap-and-sort` that normalizes field content
+    like sorting and normalizing relations or sorting the architecture field.
+
+    **Example**:
+
+    When `true`, the following:
+    ```
+    Depends: foo,
+             bar|baz
+    ```
+
+    would be reformatted as:
+
+    ```
+    Depends: bar | baz,
+             foo,
+    ```
+
+    This causes affected fields to always be rewritten and therefore be sure that other options
+    such as `formatting.deb822.short-indent` or `formatting.deb822.always-wrap` is set according
+    to taste.
+
+    Note: The field may be rewritten without this being set to `true`. As an example, the `always-wrap`
+    option can trigger a field rewrite. However, in that case, the values (including any internal whitespace)
+    are left as-is while the whitespace normalization between the values is still applied.
+    """
+        ),
+    ),
+    PreferenceOption(
+        key=["formatting", "deb822", "normalize-field-order"],
+        expected_type=bool,
+        default_value=False,
+        description=textwrap.dedent(
+            """\
+    Whether to normalize field order in a stanza.
+
+    There is no `wrap-and-sort` feature matching this.
+
+    **Example**:
+
+    When `true`, the following:
+    ```
+    Depends: bar
+    Package: foo
+    ```
+
+    would be reformatted as:
+
+    ```
+    Depends: foo
+    Package: bar
+    ```
+
+    The field order is not by field name but by a logic order defined in `debputy` based on existing
+    conventions. The `deb822` format does not dictate any field order inside stanzas in general, so
+    reordering of fields is generally safe.
+
+    If a field of the first stanza is known to be a format discriminator such as the `Format' in
+    `debian/copyright`, then it will be put first. Generally that matches existing convention plus
+    it maximizes the odds that existing tools will correctly identify the file format.
+    """
+        ),
+    ),
+    PreferenceOption(
+        key=["formatting", "deb822", "normalize-stanza-order"],
+        expected_type=bool,
+        default_value=False,
+        description=textwrap.dedent(
+            """\
+    Whether to normalize stanza order in a file.
+
+    This roughly corresponds to `wrap-and-sort`'s `-kb` feature except this may apply to other deb822
+    files.
+
+    **Example**:
+
+    When `true`, the following:
+    ```
+    Source: zzbar
+
+    Package: zzbar
+
+    Package: zzbar-util
+
+    Package: libzzbar-dev
+
+    Package: libzzbar2
+    ```
+
+    would be reformatted as:
+
+    ```
+    Source: zzbar
+
+    Package: zzbar
+
+    Package: libzzbar2
+
+    Package: libzzbar-dev
+
+    Package: zzbar-util
+    ```
+
+    Reordering will only performed when:
+      1) There is a convention for a normalized order
+      2) The normalization can be performed without changing semantics
+
+    Note: This option only guards style/preference related re-ordering. It does not influence
+    warnings about the order being semantic incorrect (which will still be emitted regardless
+    of this setting).
+    """
+        ),
+    ),
+]
+
+
+@dataclasses.dataclass(slots=True, frozen=True)
+class EffectivePreference:
+    formatting_deb822_short_indent: Optional[bool] = None
+    formatting_deb822_always_wrap: Optional[bool] = None
+    formatting_deb822_trailing_separator: bool = False
+    formatting_deb822_normalize_field_content: bool = False
+    formatting_deb822_normalize_field_order: bool = False
+    formatting_deb822_normalize_stanza_order: bool = False
+    formatting_deb822_max_line_length: int = 79
+
+    @classmethod
+    def from_file(
+        cls,
+        filename: str,
+        key: str,
+        stylees: CommentedMap,
+    ) -> Self:
+        attr = {}
+
+        for option in OPTIONS:
+            if not hasattr(cls, option.attribute_name):
+                continue
+            value = option.extract_value(filename, key, stylees)
+            attr[option.attribute_name] = value
+        return cls(**attr)  # type: ignore
+
+    @classmethod
+    def aligned_preference(
+        cls,
+        a: Optional["EffectivePreference"],
+        b: Optional["EffectivePreference"],
+    ) -> Optional["EffectivePreference"]:
+        if a is None or b is None:
+            return None
+
+        for option in OPTIONS:
+            attr_name = option.attribute_name
+            if not hasattr(EffectivePreference, attr_name):
+                continue
+            a_value = getattr(a, attr_name)
+            b_value = getattr(b, attr_name)
+            if a_value != b_value:
+                print(f"{attr_name} was misaligned")
+                return None
+        return a
+
+    def deb822_formatter(self) -> FormatterCallback:
+        line_length = self.formatting_deb822_max_line_length
+        return wrap_and_sort_formatter(
+            1 if self.formatting_deb822_short_indent else "FIELD_NAME_LENGTH",
+            trailing_separator=self.formatting_deb822_trailing_separator,
+            immediate_empty_line=self.formatting_deb822_short_indent or False,
+            max_line_length_one_liner=(
+                0 if self.formatting_deb822_always_wrap else line_length
+            ),
+        )
+
+
+@dataclasses.dataclass(slots=True, frozen=True)
+class MaintainerPreference(EffectivePreference):
+    canonical_name: Optional[str] = None
+    is_packaging_team: bool = False
+
+    def as_effective_pref(self) -> EffectivePreference:
+        fields = {
+            k: v
+            for k, v in dataclasses.asdict(self).items()
+            if hasattr(EffectivePreference, k)
+        }
+        return EffectivePreference(**fields)
+
+
+class StylePreferenceTable:
+
+    def __init__(
+        self,
+        named_styles: Mapping[str, EffectivePreference],
+        maintainer_preferences: Mapping[str, MaintainerPreference],
+    ) -> None:
+        self._named_styles = named_styles
+        self._maintainer_preferences = maintainer_preferences
+
+    @classmethod
+    def load_styles(cls) -> Self:
+        named_styles: Dict[str, EffectivePreference] = {}
+        maintainer_preferences: Dict[str, MaintainerPreference] = {}
+        with open(BUILTIN_STYLES) as fd:
+            parse_file(named_styles, maintainer_preferences, BUILTIN_STYLES, fd)
+
+        missing_keys = set(named_styles.keys()).difference(
+            ALL_PUBLIC_NAMED_STYLES.keys()
+        )
+        if missing_keys:
+            missing_styles = ", ".join(sorted(missing_keys))
+            _error(
+                f"The following named styles are public API but not present in the config file: {missing_styles}"
+            )
+
+        # TODO: Support fetching styles online to pull them in faster than waiting for a stable release.
+        return cls(named_styles, maintainer_preferences)
+
+    @property
+    def named_styles(self) -> Mapping[str, EffectivePreference]:
+        return self._named_styles
+
+    @property
+    def maintainer_preferences(self) -> Mapping[str, MaintainerPreference]:
+        return self._maintainer_preferences
+
+
+def parse_file(
+    named_styles: Dict[str, EffectivePreference],
+    maintainer_preferences: Dict[str, MaintainerPreference],
+    filename: str,
+    fd,
+) -> None:
+    content = MANIFEST_YAML.load(fd)
+    if not isinstance(content, CommentedMap):
+        raise ValueError(
+            f'The file "{filename}" should be a YAML file with a single mapping at the root'
+        )
+    try:
+        maintainer_rules = content["maintainer-rules"]
+        if not isinstance(maintainer_rules, CommentedMap):
+            raise KeyError("maintainer-rules") from None
+    except KeyError:
+        raise ValueError(
+            f'The file "{filename}" should have a "maintainer-rules" key which must be a mapping.'
+        )
+    named_styles_raw = content.get("formatting")
+    if named_styles_raw is None or not isinstance(named_styles_raw, CommentedMap):
+        named_styles_raw = {}
+
+    for style_name, content in named_styles_raw.items():
+        wrapped_style = CommentedMap({"formatting": content})
+        style = EffectivePreference.from_file(
+            filename,
+            style_name,
+            wrapped_style,
+        )
+        named_styles[style_name] = style
+
+    for maintainer_email, maintainer_styles in maintainer_rules.items():
+        if not isinstance(maintainer_styles, CommentedMap):
+            line_no = maintainer_rules.lc.key(maintainer_email).line
+            raise ValueError(
+                f'The value for maintainer "{maintainer_email}" should have been a mapping,'
+                f' but it is not. The problem entry is at line {line_no} in "{filename}"'
+            )
+        formatting = maintainer_styles.get("formatting")
+        if isinstance(formatting, str):
+            try:
+                style = named_styles_raw[formatting]
+            except KeyError:
+                line_no = maintainer_rules.lc.key(maintainer_email).line
+                raise ValueError(
+                    f'The maintainer "{maintainer_email}" requested the named style "{formatting}",'
+                    f' but said style was not defined {filename}. The problem entry is at line {line_no} in "{filename}"'
+                ) from None
+            maintainer_styles["formatting"] = style
+        maintainer_preferences[maintainer_email] = MaintainerPreference.from_file(
+            filename,
+            maintainer_email,
+            maintainer_styles,
+        )
+
+
+@functools.lru_cache(64)
+def extract_maint_email(maint: str) -> str:
+    if not maint.endswith(">"):
+        return ""
+
+    try:
+        idx = maint.index("<")
+    except ValueError:
+        return ""
+    return maint[idx + 1 : -1]
+
+
+def determine_effective_style(
+    style_preference_table: StylePreferenceTable,
+    source_package: SourcePackage,
+) -> Optional[EffectivePreference]:
+    style = source_package.fields.get("X-Style")
+    if style is not None:
+        if style not in ALL_PUBLIC_NAMED_STYLES:
+            return None
+        return style_preference_table.named_styles.get(style)
+
+    maint = source_package.fields.get("Maintainer")
+    if maint is None:
+        return None
+    maint_email = extract_maint_email(maint)
+    maint_style = style_preference_table.maintainer_preferences.get(maint_email)
+    # Special-case "@packages.debian.org" when missing, since they are likely to be "ad-hoc"
+    # teams that will not be registered. In that case, we fall back to looking at the uploader
+    # preferences as-if the maintainer had not been listed at all.
+    if maint_style is None and not maint_email.endswith("@packages.debian.org"):
+        return None
+    if maint_style is not None and maint_style.is_packaging_team:
+        # When the maintainer is registered as a packaging team, then we assume the packaging
+        # team's style applies unconditionally.
+        return maint_style.as_effective_pref()
+    uploaders = source_package.fields.get("Uploaders")
+    if uploaders is None:
+        return maint_style.as_effective_pref() if maint_style is not None else None
+    all_styles: List[Optional[EffectivePreference]] = []
+    if maint_style is not None:
+        all_styles.append(maint_style)
+    for uploader in _UPLOADER_SPLIT_RE.split(uploaders):
+        uploader_email = extract_maint_email(uploader)
+        uploader_style = style_preference_table.maintainer_preferences.get(
+            uploader_email
+        )
+        all_styles.append(uploader_style)
+
+    if not all_styles:
+        return None
+    r = functools.reduce(EffectivePreference.aligned_preference, all_styles)
+    if isinstance(r, MaintainerPreference):
+        return r.as_effective_pref()
+    return r
diff --git a/src/debputy/lsp/text_edit.py b/src/debputy/lsp/text_edit.py
index 770a837..4b210b2 100644
--- a/src/debputy/lsp/text_edit.py
+++ b/src/debputy/lsp/text_edit.py
@@ -4,7 +4,7 @@
 # Copyright 2021- Python Language Server Contributors.
 # License: Expat (MIT/X11)
 #
-from typing import List
+from typing import List, Sequence
 
 from lsprotocol.types import Range, TextEdit, Position
 
@@ -88,7 +88,11 @@ def offset_at_position(lines: List[str], server_position: Position) -> int:
     return col + sum(len(line) for line in lines[:row])
 
 
-def apply_text_edits(text: str, lines: List[str], text_edits: List[TextEdit]) -> str:
+def apply_text_edits(
+    text: str,
+    lines: List[str],
+    text_edits: Sequence[TextEdit],
+) -> str:
     sorted_edits = merge_sort_text_edits(
         [get_well_formatted_edit(e) for e in text_edits]
     )
diff --git a/src/debputy/lsp/text_util.py b/src/debputy/lsp/text_util.py
index ef4cd0a..e58990f 100644
--- a/src/debputy/lsp/text_util.py
+++ b/src/debputy/lsp/text_util.py
@@ -5,6 +5,7 @@ from lsprotocol.types import (
     Position,
     Range,
     WillSaveTextDocumentParams,
+    DocumentFormattingParams,
 )
 
 from debputy.linting.lint_util import LinterPositionCodec
@@ -73,18 +74,24 @@ def normalize_dctrl_field_name(f: str) -> str:
 
 def on_save_trim_end_of_line_whitespace(
     ls: "LanguageServer",
-    params: WillSaveTextDocumentParams,
+    params: Union[WillSaveTextDocumentParams, DocumentFormattingParams],
 ) -> Optional[Sequence[TextEdit]]:
     doc = ls.workspace.get_text_document(params.text_document.uri)
-    return trim_end_of_line_whitespace(doc, doc.lines)
+    return trim_end_of_line_whitespace(doc.position_codec, doc.lines)
 
 
 def trim_end_of_line_whitespace(
-    doc: "TextDocument",
+    position_codec: "LintCapablePositionCodec",
     lines: List[str],
+    *,
+    line_range: Optional[Iterable[int]] = None,
+    line_relative_line_no: int = 0,
 ) -> Optional[Sequence[TextEdit]]:
     edits = []
-    for line_no, orig_line in enumerate(lines):
+    if line_range is None:
+        line_range = range(0, len(lines))
+    for line_no in line_range:
+        orig_line = lines[line_no]
         orig_len = len(orig_line)
         if orig_line.endswith("\n"):
             orig_len -= 1
@@ -92,16 +99,20 @@ def trim_end_of_line_whitespace(
         if stripped_len == orig_len:
             continue
 
-        edit_range = doc.position_codec.range_to_client_units(
+        stripped_len_client_off = position_codec.client_num_units(
+            orig_line[:stripped_len]
+        )
+        orig_len_client_off = position_codec.client_num_units(orig_line[:orig_len])
+        edit_range = position_codec.range_to_client_units(
             lines,
             Range(
                 Position(
-                    line_no,
-                    stripped_len,
+                    line_no + line_relative_line_no,
+                    stripped_len_client_off,
                 ),
                 Position(
-                    line_no,
-                    orig_len,
+                    line_no + line_relative_line_no,
+                    orig_len_client_off,
                 ),
             ),
         )
diff --git a/src/debputy/lsp/vendoring/_deb822_repro/_util.py b/src/debputy/lsp/vendoring/_deb822_repro/_util.py
index a79426d..0e68a03 100644
--- a/src/debputy/lsp/vendoring/_deb822_repro/_util.py
+++ b/src/debputy/lsp/vendoring/_deb822_repro/_util.py
@@ -279,7 +279,7 @@ def len_check_iterator(
             Value parser did not fully cover the entire line with tokens (
             missing range {covered}..{content_len}).  Occurred when parsing "{content}"
             """
-            ).format(covered=covered, content_len=content_len, line=content)
+            ).format(covered=covered, content_len=content_len, content=content)
             raise ValueError(msg)
         msg = textwrap.dedent(
             """\
diff --git a/src/debputy/lsp/vendoring/_deb822_repro/formatter.py b/src/debputy/lsp/vendoring/_deb822_repro/formatter.py
index a2b797b..066fa3f 100644
--- a/src/debputy/lsp/vendoring/_deb822_repro/formatter.py
+++ b/src/debputy/lsp/vendoring/_deb822_repro/formatter.py
@@ -207,6 +207,7 @@ def one_value_per_line_formatter(
             indent_len = len(name) + 2
         else:
             indent_len = indentation
+            assert isinstance(indent_len, int)  # hint for PyCharm
         indent = " " * indent_len
 
         emitted_first_line = False
diff --git a/src/debputy/lsp/vendoring/_deb822_repro/locatable.py b/src/debputy/lsp/vendoring/_deb822_repro/locatable.py
index afebf14..b5da920 100644
--- a/src/debputy/lsp/vendoring/_deb822_repro/locatable.py
+++ b/src/debputy/lsp/vendoring/_deb822_repro/locatable.py
@@ -52,9 +52,7 @@ class Position:
         >>> parent: Locatable = ...                   # doctest: +SKIP
         >>> children: Iterable[Locatable] = ...       # doctest: +SKIP
         >>> # This will expensive
-        >>> parent_pos = parent.position_in_file(     # doctest: +SKIP
-        ...    skip_leading_comments=False
-        ... )
+        >>> parent_pos = parent.position_in_file()     # doctest: +SKIP
         >>> for child in children:                    # doctest: +SKIP
         ...    child_pos = child.position_in_parent()
         ...    # Avoid a position_in_file() for each child
@@ -181,9 +179,7 @@ class Range:
         >>> parent: Locatable = ...                   # doctest: +SKIP
         >>> children: Iterable[Locatable] = ...       # doctest: +SKIP
         >>> # This will expensive
-        >>> parent_pos = parent.position_in_file(     # doctest: +SKIP
-        ...    skip_leading_comments=False
-        ... )
+        >>> parent_pos = parent.position_in_file()     # doctest: +SKIP
         >>> for child in children:                    # doctest: +SKIP
         ...    child_range = child.range_in_parent()
         ...    # Avoid a position_in_file() for each child
@@ -312,26 +308,12 @@ class Locatable:
         # type: () -> Optional[Deb822Element]
         raise NotImplementedError
 
-    def position_in_parent(self, *, skip_leading_comments: bool = True) -> Position:
+    def position_in_parent(self) -> Position:
         """The start position of this token/element inside its parent
 
         This is operation is generally linear to the number of "parts" (elements/tokens)
         inside the parent.
-
-        :param skip_leading_comments: If True, then if any leading comment that
-          that can be skipped will be excluded in the position of this locatable.
-          This is useful if you want the position "semantic" content of a field
-          without also highlighting a leading comment. Remember to align this
-          parameter with the `size` call, so the range does not "overshoot"
-          into the next element (or falls short and only covers part of an
-          element). Note that this option can only be used to filter out leading
-          comments when the comments are a subset of the element. It has no
-          effect on elements that are entirely made of comments.
         """
-        # pylint: disable=unused-argument
-        # Note: The base class makes no assumptions about what tokens can be skipped,
-        # therefore, skip_leading_comments is unused here. However, I do not want the
-        # API to differ between elements and tokens.
 
         parent = self.parent_element
         if parent is None:
@@ -343,32 +325,23 @@ class Locatable:
         )
         span = Range.from_position_and_sizes(
             START_POSITION,
-            (x.size(skip_leading_comments=False) for x in relevant_parts),
+            (x.size() for x in relevant_parts),
         )
         return span.end_pos
 
-    def range_in_parent(self, *, skip_leading_comments: bool = True) -> Range:
+    def range_in_parent(self) -> Range:
         """The range of this token/element inside its parent
 
         This is operation is generally linear to the number of "parts" (elements/tokens)
         inside the parent.
-
-        :param skip_leading_comments: If True, then if any leading comment that
-          that can be skipped will be excluded in the position of this locatable.
-          This is useful if you want the position "semantic" content of a field
-          without also highlighting a leading comment. Remember to align this
-          parameter with the `size` call, so the range does not "overshoot"
-          into the next element (or falls short and only covers part of an
-          element). Note that this option can only be used to filter out leading
-          comments when the comments are a subset of the element. It has no
-          effect on elements that are entirely made of comments.
         """
-        pos = self.position_in_parent(skip_leading_comments=skip_leading_comments)
+        pos = self.position_in_parent()
         return Range.from_position_and_size(
-            pos, self.size(skip_leading_comments=skip_leading_comments)
+            pos,
+            self.size(),
         )
 
-    def position_in_file(self, *, skip_leading_comments: bool = True) -> Position:
+    def position_in_file(self) -> Position:
         """The start position of this token/element in this file
 
         This is an *expensive* operation and in many cases have to traverse
@@ -377,37 +350,14 @@ class Locatable:
         `position_in_parent()` combined with
         `child_position.relative_to(parent_position)`
 
-        :param skip_leading_comments: If True, then if any leading comment that
-          that can be skipped will be excluded in the position of this locatable.
-          This is useful if you want the position "semantic" content of a field
-          without also highlighting a leading comment. Remember to align this
-          parameter with the `size` call, so the range does not "overshoot"
-          into the next element (or falls short and only covers part of an
-          element). Note that this option can only be used to filter out leading
-          comments when the comments are a subset of the element. It has no
-          effect on elements that are entirely made of comments.
         """
-        position = self.position_in_parent(
-            skip_leading_comments=skip_leading_comments,
-        )
+        position = self.position_in_parent()
         parent = self.parent_element
         if parent is not None:
-            parent_position = parent.position_in_file(skip_leading_comments=False)
+            parent_position = parent.position_in_file()
             position = position.relative_to(parent_position)
         return position
 
-    def size(self, *, skip_leading_comments: bool = True) -> Range:
-        """Describe the objects size as a continuous range
-
-        :param skip_leading_comments: If True, then if any leading comment that
-          that can be skipped will be excluded in the position of this locatable.
-          This is useful if you want the position "semantic" content of a field
-          without also highlighting a leading comment. Remember to align this
-          parameter with the `position_in_file` or `position_in_parent` call,
-          so the range does not "overshoot" into the next element (or falls
-          short and only covers part of an element).  Note that this option can
-          only be used to filter out leading comments when the comments are a
-          subset of the element. It has no effect on elements that are entirely
-          made of comments.
-        """
+    def size(self) -> Range:
+        """Describe the objects size as a continuous range"""
         raise NotImplementedError
diff --git a/src/debputy/lsp/vendoring/_deb822_repro/parsing.py b/src/debputy/lsp/vendoring/_deb822_repro/parsing.py
index c5753e2..71aa79a 100644
--- a/src/debputy/lsp/vendoring/_deb822_repro/parsing.py
+++ b/src/debputy/lsp/vendoring/_deb822_repro/parsing.py
@@ -620,8 +620,7 @@ class Deb822ParsedTokenList(
         # type: () -> str
         return "".join(t.text for t in self._iter_content_as_tokens())
 
-    def _update_field(self):
-        # type: () -> None
+    def _generate_kvpair(self) -> "Deb822KeyValuePairElement":
         kvpair_element = self._kvpair_element
         field_name = kvpair_element.field_name
         token_list = self._token_list
@@ -669,7 +668,17 @@ class Deb822ParsedTokenList(
         assert isinstance(paragraph, Deb822NoDuplicateFieldsParagraphElement)
         new_kvpair_element = paragraph.get_kvpair_element(field_name)
         assert new_kvpair_element is not None
-        kvpair_element.value_element = new_kvpair_element.value_element
+        return new_kvpair_element
+
+    def convert_to_text(self, *, with_field_name: bool = False) -> str:
+        kvpair = self._generate_kvpair()
+        element = kvpair if with_field_name else kvpair.value_element
+        return element.convert_to_text()
+
+    def _update_field(self):
+        # type: () -> None
+        kvpair_element = self._kvpair_element
+        kvpair_element.value_element = self._generate_kvpair().value_element
         self._changed = False
 
     def sort_elements(
@@ -1119,12 +1128,12 @@ class Deb822Element(Locatable):
         if parent is self.parent_element:
             self._parent_element = None
 
-    def size(self, *, skip_leading_comments: bool = True) -> Range:
+    def size(self) -> Range:
         size_cache = self._full_size_cache
         if size_cache is None:
             size_cache = Range.from_position_and_sizes(
                 START_POSITION,
-                (p.size(skip_leading_comments=False) for p in self.iter_parts()),
+                (p.size() for p in self.iter_parts()),
             )
             self._full_size_cache = size_cache
         return size_cache
@@ -1147,21 +1156,21 @@ class Deb822InterpretationProxyElement(Deb822Element):
         # type: () -> Iterable[TokenOrElement]
         return iter(self.parts)
 
-    def position_in_parent(self, *, skip_leading_comments: bool = True) -> Position:
+    def position_in_parent(self) -> Position:
         parent = self.parent_element
         if parent is None:
             raise RuntimeError("parent was garbage collected")
         return parent.position_in_parent()
 
-    def position_in_file(self, *, skip_leading_comments: bool = True) -> Position:
+    def position_in_file(self) -> Position:
         parent = self.parent_element
         if parent is None:
             raise RuntimeError("parent was garbage collected")
         return parent.position_in_file()
 
-    def size(self, *, skip_leading_comments: bool = True) -> Range:
+    def size(self) -> Range:
         # Same as parent except we never use a cache.
-        sizes = (p.size(skip_leading_comments=False) for p in self.iter_parts())
+        sizes = (p.size() for p in self.iter_parts())
         return Range.from_position_and_sizes(START_POSITION, sizes)
 
 
@@ -1294,28 +1303,6 @@ class Deb822ValueLineElement(Deb822Element):
         if self._newline_token:
             yield self._newline_token
 
-    def size(self, *, skip_leading_comments: bool = True) -> Range:
-        if skip_leading_comments:
-            return Range.from_position_and_sizes(
-                START_POSITION,
-                (
-                    p.size(skip_leading_comments=False)
-                    for p in self.iter_parts()
-                    if not p.is_comment
-                ),
-            )
-        return super().size(skip_leading_comments=skip_leading_comments)
-
-    def position_in_parent(self, *, skip_leading_comments: bool = True) -> Position:
-        base_pos = super().position_in_parent(skip_leading_comments=False)
-        if skip_leading_comments:
-            for p in self.iter_parts():
-                if p.is_comment:
-                    continue
-                non_comment_pos = p.position_in_parent(skip_leading_comments=False)
-                base_pos = non_comment_pos.relative_to(base_pos)
-        return base_pos
-
 
 class Deb822ValueElement(Deb822Element):
     __slots__ = ("_value_entry_elements",)
@@ -1503,43 +1490,9 @@ class Deb822KeyValuePairElement(Deb822Element):
         yield self._separator_token
         yield self._value_element
 
-    def key_position_in_stanza(self) -> Position:
-        position = super().position_in_parent(skip_leading_comments=False)
-        if self._comment_element:
-            field_pos = self._field_token.position_in_parent()
-            position = field_pos.relative_to(position)
-        return position
-
     def value_position_in_stanza(self) -> Position:
-        position = super().position_in_parent(skip_leading_comments=False)
-        if self._comment_element:
-            value_pos = self._value_element.position_in_parent()
-            position = value_pos.relative_to(position)
-        return position
-
-    def position_in_parent(
-        self,
-        *,
-        skip_leading_comments: bool = True,
-    ) -> Position:
-        position = super().position_in_parent(skip_leading_comments=False)
-        if skip_leading_comments:
-            if self._comment_element:
-                field_pos = self._field_token.position_in_parent()
-                position = field_pos.relative_to(position)
-        return position
-
-    def size(self, *, skip_leading_comments: bool = True) -> Range:
-        if skip_leading_comments:
-            return Range.from_position_and_sizes(
-                START_POSITION,
-                (
-                    p.size(skip_leading_comments=False)
-                    for p in self.iter_parts()
-                    if not p.is_comment
-                ),
-            )
-        return super().size(skip_leading_comments=False)
+        value_pos = self._value_element.position_in_parent()
+        return value_pos.relative_to(self.position_in_parent())
 
 
 def _format_comment(c):
@@ -3167,11 +3120,11 @@ class Deb822FileElement(Deb822Element):
         t.parent_element = self
         return t
 
-    def position_in_parent(self, *, skip_leading_comments: bool = True) -> Position:
+    def position_in_parent(self) -> Position:
         # Recursive base-case
         return START_POSITION
 
-    def position_in_file(self, *, skip_leading_comments: bool = True) -> Position:
+    def position_in_file(self) -> Position:
         # By definition
         return START_POSITION
 
diff --git a/src/debputy/lsp/vendoring/_deb822_repro/tokens.py b/src/debputy/lsp/vendoring/_deb822_repro/tokens.py
index 88d2058..b11b580 100644
--- a/src/debputy/lsp/vendoring/_deb822_repro/tokens.py
+++ b/src/debputy/lsp/vendoring/_deb822_repro/tokens.py
@@ -174,7 +174,7 @@ class Deb822Token(Locatable):
         # type: () -> str
         return self._text
 
-    def size(self, *, skip_leading_comments: bool = False) -> Range:
+    def size(self) -> Range:
         # As tokens are an atomic unit
         token_size = self._token_size
         if token_size is not None:
@@ -499,6 +499,11 @@ def _value_line_tokenizer(func):
 def whitespace_split_tokenizer(v):
     # type: (str) -> Iterable[Deb822Token]
     assert "\n" not in v
+    if not v or v.isspace():
+        # Special-case: Empty field/whitespace only field
+        if v:
+            yield Deb822SpaceSeparatorToken(sys.intern(v))
+        return
     for match in _RE_WHITESPACE_SEPARATED_WORD_LIST.finditer(v):
         space_before, word, space_after = match.groups()
         if space_before:
diff --git a/src/debputy/lsp/vendoring/wrap_and_sort.py b/src/debputy/lsp/vendoring/wrap_and_sort.py
new file mode 100644
index 0000000..5b25891
--- /dev/null
+++ b/src/debputy/lsp/vendoring/wrap_and_sort.py
@@ -0,0 +1,113 @@
+# Code extracted from devscripts/wrap-and-sort with typing added
+import re
+from typing import Tuple, Iterable, Literal, Union
+
+from debputy.lsp.vendoring._deb822_repro.formatter import (
+    one_value_per_line_formatter,
+    FormatterContentToken,
+)
+from debputy.lsp.vendoring._deb822_repro.types import FormatterCallback
+
+PACKAGE_SORT = re.compile("^[a-z0-9]")
+
+
+def _sort_packages_key(package: str) -> Tuple[int, str]:
+    # Sort dependencies starting with a "real" package name before ones starting
+    # with a substvar
+    return 0 if PACKAGE_SORT.search(package) else 1, package
+
+
+def _emit_one_line_value(
+    value_tokens: Iterable[FormatterContentToken],
+    sep_token: FormatterContentToken,
+    trailing_separator: bool,
+) -> Iterable[Union[str, FormatterContentToken]]:
+    first_token = True
+    yield " "
+    for token in value_tokens:
+        if not first_token:
+            yield sep_token
+            if not sep_token.is_whitespace:
+                yield " "
+        first_token = False
+        yield token
+    if trailing_separator and not sep_token.is_whitespace:
+        yield sep_token
+    yield "\n"
+
+
+def wrap_and_sort_formatter(
+    indentation: Union[int, Literal["FIELD_NAME_LENGTH"]],
+    trailing_separator: bool = True,
+    immediate_empty_line: bool = False,
+    max_line_length_one_liner: int = 0,
+) -> FormatterCallback:
+    """Provide a formatter that can handle indentation and trailing separators
+
+    This is a custom wrap-and-sort formatter capable of supporting wrap-and-sort's
+    needs. Where possible it delegates to python-debian's own formatter.
+
+    :param indentation: Either the literal string "FIELD_NAME_LENGTH" or a positive
+    integer, which determines the indentation fields.  If it is an integer,
+    then a fixed indentation is used (notably the value 1 ensures the shortest
+    possible indentation).  Otherwise, if it is "FIELD_NAME_LENGTH", then the
+    indentation is set such that it aligns the values based on the field name.
+    This parameter only affects values placed on the second line or later lines.
+    :param trailing_separator: If True, then the last value will have a trailing
+    separator token (e.g., ",") after it.
+    :param immediate_empty_line: Whether the value should always start with an
+    empty line.  If True, then the result becomes something like "Field:\n value".
+    This parameter only applies to the values that will be formatted over more than
+    one line.
+    :param max_line_length_one_liner: If greater than zero, then this is the max length
+    of the value if it is crammed into a "one-liner" value.  If the value(s) fit into
+    one line, this parameter will overrule immediate_empty_line.
+
+    """
+    if indentation != "FIELD_NAME_LENGTH" and indentation < 1:
+        raise ValueError('indentation must be at least 1 (or "FIELD_NAME_LENGTH")')
+
+    # The python-debian library provides support for all cases except cramming
+    # everything into a single line.  So we "only" have to implement the single-line
+    # case(s) ourselves (which sadly takes plenty of code on its own)
+
+    _chain_formatter = one_value_per_line_formatter(
+        indentation,
+        trailing_separator=trailing_separator,
+        immediate_empty_line=immediate_empty_line,
+    )
+
+    if max_line_length_one_liner < 1:
+        return _chain_formatter
+
+    def _formatter(name, sep_token, formatter_tokens):
+        # We should have unconditionally delegated to the python-debian formatter
+        # if max_line_length_one_liner was set to "wrap_always"
+        assert max_line_length_one_liner > 0
+        all_tokens = list(formatter_tokens)
+        values_and_comments = [x for x in all_tokens if x.is_comment or x.is_value]
+        # There are special-cases where you could do a one-liner with comments, but
+        # they are probably a lot more effort than it is worth investing.
+        # - If you are here because you disagree, patches welcome. :)
+        if all(x.is_value for x in values_and_comments):
+            # We use " " (1 char) or ", " (2 chars) as separated depending on the field.
+            # (at the time of writing, wrap-and-sort only uses this formatted for
+            # dependency fields meaning this will be "2" - but now it is future proof).
+            chars_between_values = 1 + (0 if sep_token.is_whitespace else 1)
+            # Compute the total line length of the field as the sum of all values
+            total_len = sum(len(x.text) for x in values_and_comments)
+            # ... plus the separators
+            total_len += (len(values_and_comments) - 1) * chars_between_values
+            # plus the field name + the ": " after the field name
+            total_len += len(name) + 2
+            if total_len <= max_line_length_one_liner:
+                yield from _emit_one_line_value(
+                    values_and_comments, sep_token, trailing_separator
+                )
+                return
+            # If it does not fit in one line, we fall through
+        # Chain into the python-debian provided formatter, which will handle this
+        # formatting for us.
+        yield from _chain_formatter(name, sep_token, iter(all_tokens))
+
+    return _formatter
diff --git a/src/debputy/util.py b/src/debputy/util.py
index d8cfd67..11f6ccd 100644
--- a/src/debputy/util.py
+++ b/src/debputy/util.py
@@ -763,8 +763,8 @@ def setup_logging(
             colorlog.ColoredFormatter(color_format, style="{", force_color=True)
         )
         logger = logging.getLogger()
-        if existing_stdout_handler is not None:
-            logger.removeHandler(existing_stdout_handler)
+        if existing_stderr_handler is not None:
+            logger.removeHandler(existing_stderr_handler)
         _STDERR_HANDLER = stderr_handler
         logger.addHandler(stderr_handler)
     else:
diff --git a/tests/lint_tests/conftest.py b/tests/lint_tests/conftest.py
index 2c54eb7..bf4b3b0 100644
--- a/tests/lint_tests/conftest.py
+++ b/tests/lint_tests/conftest.py
@@ -3,6 +3,7 @@ from debian.debian_support import DpkgArchTable
 
 from debputy._deb_options_profiles import DebBuildOptionsAndProfiles
 from debputy.architecture_support import DpkgArchitectureBuildProcessValuesTable
+from debputy.lsp.style_prefs import StylePreferenceTable
 from debputy.packages import DctrlParser
 from debputy.util import setup_logging
 
diff --git a/tests/lint_tests/lint_tutil.py b/tests/lint_tests/lint_tutil.py
index 83b69fd..8290712 100644
--- a/tests/lint_tests/lint_tutil.py
+++ b/tests/lint_tests/lint_tutil.py
@@ -9,6 +9,7 @@ from debputy.linting.lint_util import (
     LintStateImpl,
     LintState,
 )
+from debputy.lsp.style_prefs import StylePreferenceTable, EffectivePreference
 from debputy.packages import DctrlParser
 from debputy.plugin.api.feature_set import PluginProvidedFeatureSet
 
@@ -43,6 +44,8 @@ class LintWrapper:
         self.dctrl_lines: Optional[List[str]] = None
         self.path = path
         self._dctrl_parser = dctrl_parser
+        self.lint_style_preference_table = StylePreferenceTable({}, {})
+        self.effective_preference: Optional[EffectivePreference] = None
 
     def __call__(self, lines: List[str]) -> Optional[List["Diagnostic"]]:
         source_package = None
@@ -56,10 +59,13 @@ class LintWrapper:
             )
         state = LintStateImpl(
             self._debputy_plugin_feature_set,
+            self.lint_style_preference_table,
             self.path,
+            "".join(dctrl_lines) if dctrl_lines is not None else "",
             lines,
             source_package,
             binary_packages,
+            self.effective_preference,
         )
         return check_diagnostics(self._handler(state))
 
diff --git a/tests/lint_tests/test_lint_dctrl.py b/tests/lint_tests/test_lint_dctrl.py
index ce34d7c..bcb1613 100644
--- a/tests/lint_tests/test_lint_dctrl.py
+++ b/tests/lint_tests/test_lint_dctrl.py
@@ -18,6 +18,9 @@ except ImportError:
     pass
 
 
+STANDARDS_VERSION = "4.7.0"
+
+
 class DctrlLintWrapper(LintWrapper):
 
     def __call__(self, lines: List[str]) -> Optional[List["Diagnostic"]]:
@@ -93,15 +96,15 @@ def test_dctrl_lint(line_linter: LintWrapper) -> None:
 
     msg = 'The value "base" is not supported in Section.'
     assert second_warn.message == msg
-    assert f"{second_warn.range}" == "8:9-8:13"
+    assert f"{second_warn.range}" == "7:9-7:13"
 
 
 @requires_levenshtein
 def test_dctrl_lint_typos(line_linter: LintWrapper) -> None:
     lines = textwrap.dedent(
-        """\
+        f"""\
     Source: foo
-    Standards-Version: 4.5.2
+    Standards-Version: {STANDARDS_VERSION}
     Priority: optional
     Section: devel
     Maintainer: Jane Developer <jane@example.com>
@@ -132,9 +135,9 @@ def test_dctrl_lint_typos(line_linter: LintWrapper) -> None:
 @requires_levenshtein
 def test_dctrl_lint_mx_value_with_typo(line_linter: LintWrapper) -> None:
     lines = textwrap.dedent(
-        """\
+        f"""\
     Source: foo
-    Standards-Version: 4.5.2
+    Standards-Version: {STANDARDS_VERSION}
     Priority: optional
     Section: devel
     Maintainer: Jane Developer <jane@example.com>
@@ -165,15 +168,15 @@ def test_dctrl_lint_mx_value_with_typo(line_linter: LintWrapper) -> None:
     typo_msg = 'It is possible that the value is a typo of "all".'
     assert mx_diag.message == mx_msg
     assert typo_diag.message == typo_msg
-    assert f"{mx_diag.range}" == "10:24-10:28"
-    assert f"{typo_diag.range}" == "10:24-10:28"
+    assert f"{mx_diag.range}" == "9:24-9:28"
+    assert f"{typo_diag.range}" == "9:24-9:28"
 
 
 def test_dctrl_lint_mx_value(line_linter: LintWrapper) -> None:
     lines = textwrap.dedent(
-        """\
+        f"""\
     Source: foo
-    Standards-Version: 4.5.2
+    Standards-Version: {STANDARDS_VERSION}
     Priority: optional
     Section: devel
     Maintainer: Jane Developer <jane@example.com>
@@ -200,9 +203,9 @@ def test_dctrl_lint_mx_value(line_linter: LintWrapper) -> None:
     assert f"{diag.range}" == "8:14-8:17"
 
     lines = textwrap.dedent(
-        """\
+        f"""\
     Source: foo
-    Standards-Version: 4.5.2
+    Standards-Version: {STANDARDS_VERSION}
     Priority: optional
     Section: devel
     Maintainer: Jane Developer <jane@example.com>
@@ -227,3 +230,36 @@ def test_dctrl_lint_mx_value(line_linter: LintWrapper) -> None:
     assert diag.message == msg
     assert diag.severity == DiagnosticSeverity.Error
     assert f"{diag.range}" == "8:24-8:27"
+
+
+def test_dctrl_lint_dup_sep(line_linter: LintWrapper) -> None:
+    lines = textwrap.dedent(
+        f"""\
+    Source: foo
+    Section: devel
+    Priority: optional
+    Standards-Version: {STANDARDS_VERSION}
+    Maintainer: Jane Developer <jane@example.com>
+    Build-Depends: debhelper-compat (= 13)
+
+    Package: foo
+    Architecture: all
+    Depends: foo,
+     , bar
+    Description: Some very interesting synopsis
+     A very interesting description
+     that spans multiple lines
+     .
+     Just so be clear, this is for a test.
+    """
+    ).splitlines(keepends=True)
+
+    diagnostics = line_linter(lines)
+    print(diagnostics)
+    assert diagnostics and len(diagnostics) == 1
+    error = diagnostics[0]
+
+    msg = "Duplicate separator"
+    assert error.message == msg
+    assert f"{error.range}" == "10:1-10:2"
+    assert error.severity == DiagnosticSeverity.Error
diff --git a/tests/lsp_tests/test_debpkg_metadata.py b/tests/lsp_tests/test_debpkg_metadata.py
index f784b0a..fdb0df8 100644
--- a/tests/lsp_tests/test_debpkg_metadata.py
+++ b/tests/lsp_tests/test_debpkg_metadata.py
@@ -19,7 +19,7 @@ from debputy.lsp.lsp_debian_control_reference_data import package_name_to_sectio
         ("xxx-l10n-bar", "localization"),
         ("libfoo4", "libs"),
         ("unknown", None),
-    ]
+    ],
 )
 def test_package_name_to_section(name: str, guessed_section: Optional[str]) -> None:
     assert package_name_to_section(name) == guessed_section
diff --git a/tests/test_style.py b/tests/test_style.py
new file mode 100644
index 0000000..9ce83bd
--- /dev/null
+++ b/tests/test_style.py
@@ -0,0 +1,121 @@
+import pytest
+from debian.deb822 import Deb822
+
+from debputy.lsp.style_prefs import StylePreferenceTable, determine_effective_style
+from debputy.packages import SourcePackage
+
+
+def test_load_styles() -> None:
+    styles = StylePreferenceTable.load_styles()
+    assert "niels@thykier.net" in styles.maintainer_preferences
+    nt_style = styles.maintainer_preferences["niels@thykier.net"]
+    # Note this is data dependent; if it fails because the style changes, update the test
+    assert nt_style.canonical_name == "Niels Thykier"
+    assert not nt_style.is_packaging_team
+    assert nt_style.formatting_deb822_normalize_field_content
+    assert nt_style.formatting_deb822_short_indent
+    assert nt_style.formatting_deb822_always_wrap
+    assert nt_style.formatting_deb822_trailing_separator
+    assert nt_style.formatting_deb822_max_line_length == 79
+    assert nt_style.formatting_deb822_normalize_stanza_order
+
+    # TODO: Not implemented yet
+    assert not nt_style.formatting_deb822_normalize_field_order
+
+
+def test_load_named_styles() -> None:
+    styles = StylePreferenceTable.load_styles()
+    assert "black" in styles.named_styles
+    black_style = styles.named_styles["black"]
+    # Note this is data dependent; if it fails because the style changes, update the test
+    assert black_style.formatting_deb822_normalize_field_content
+    assert black_style.formatting_deb822_short_indent
+    assert black_style.formatting_deb822_always_wrap
+    assert black_style.formatting_deb822_trailing_separator
+    assert black_style.formatting_deb822_max_line_length == 79
+    assert black_style.formatting_deb822_normalize_stanza_order
+
+    # TODO: Not implemented yet
+    assert not black_style.formatting_deb822_normalize_field_order
+
+
+def test_compat_styles() -> None:
+    styles = StylePreferenceTable.load_styles()
+
+    # Data dependent; if it breaks, provide a stubbed style preference table
+    assert "niels@thykier.net" in styles.maintainer_preferences
+    assert "zeha@debian.org" in styles.maintainer_preferences
+    assert "random-package@packages.debian.org" not in styles.maintainer_preferences
+    assert "random@example.org" not in styles.maintainer_preferences
+
+    nt_pref = styles.maintainer_preferences["niels@thykier.net"].as_effective_pref()
+    zeha_pref = styles.maintainer_preferences["zeha@debian.org"].as_effective_pref()
+
+    # Data dependency
+    assert nt_pref == zeha_pref
+
+    fields = Deb822(
+        {
+            "Package": "foo",
+            "Maintainer": "Foo <random-package@packages.debian.org>",
+            "Uploaders": "Niels Thykier <niels@thykier.net>",
+        },
+    )
+    src = SourcePackage(fields)
+
+    effective_style = determine_effective_style(styles, src)
+    assert effective_style == nt_pref
+
+    fields["Uploaders"] = (
+        "Niels Thykier <niels@thykier.net>, Chris Hofstaedtler <zeha@debian.org>"
+    )
+    src = SourcePackage(fields)
+
+    effective_style = determine_effective_style(styles, src)
+    assert effective_style == nt_pref
+    assert effective_style == zeha_pref
+
+    fields["Uploaders"] = (
+        "Niels Thykier <niels@thykier.net>, Chris Hofstaedtler <zeha@debian.org>, Random Developer <random@example.org>"
+    )
+    src = SourcePackage(fields)
+
+    effective_style = determine_effective_style(styles, src)
+    assert effective_style is None
+
+
+@pytest.mark.xfail
+def test_compat_styles_team_maint() -> None:
+    styles = StylePreferenceTable.load_styles()
+    fields = Deb822(
+        {
+            "Package": "foo",
+            # Missing a stubbed definition for `team@lists.debian.org`
+            "Maintainer": "Packaging Team <team@lists.debian.org>",
+            "Uploaders": "Random Developer <random@example.org>",
+        },
+    )
+    src = SourcePackage(fields)
+    assert "team@lists.debian.org" in styles.maintainer_preferences
+    assert "random@example.org" not in styles.maintainer_preferences
+    team_style = styles.maintainer_preferences["team@lists.debian.org"]
+    assert team_style.is_packaging_team
+    effective_style = determine_effective_style(styles, src)
+    assert effective_style == team_style.as_effective_pref()
+
+
+def test_x_style() -> None:
+    styles = StylePreferenceTable.load_styles()
+    fields = Deb822(
+        {
+            "Package": "foo",
+            "X-Style": "black",
+            "Maintainer": "Random Developer <random@example.org>",
+        },
+    )
+    src = SourcePackage(fields)
+    assert "random@example.org" not in styles.maintainer_preferences
+    assert "black" in styles.named_styles
+    black_style = styles.named_styles["black"]
+    effective_style = determine_effective_style(styles, src)
+    assert effective_style == black_style