Adding upstream version 115.7.0esr.upstream/115.7.0esr

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

1 files changed, 996 insertions, 0 deletions

diff --git a/testing/web-platform/tests/tools/lint/lint.py b/testing/web-platform/tests/tools/lint/lint.py
new file mode 100644
index 0000000000..9fc78d9b68
--- /dev/null
+++ b/testing/web-platform/tests/tools/lint/lint.py
@@ -0,0 +1,996 @@
+import abc
+import argparse
+import ast
+import json
+import logging
+import multiprocessing
+import os
+import re
+import subprocess
+import sys
+import tempfile
+from collections import defaultdict
+from typing import (Any, Callable, Dict, IO, Iterable, List, Optional, Sequence, Set, Text, Tuple,
+                    Type, TypeVar)
+
+from urllib.parse import urlsplit, urljoin
+
+try:
+    from xml.etree import cElementTree as ElementTree
+except ImportError:
+    from xml.etree import ElementTree as ElementTree  # type: ignore
+
+from . import fnmatch
+from . import rules
+from .. import localpaths
+from ..ci.tc.github_checks_output import get_gh_checks_outputter, GitHubChecksOutputter
+from ..gitignore.gitignore import PathFilter
+from ..wpt import testfiles
+from ..manifest.vcs import walk
+
+from ..manifest.sourcefile import SourceFile, js_meta_re, python_meta_re, space_chars, get_any_variants
+
+
+# The Ignorelist is a two level dictionary. The top level is indexed by
+# error names (e.g. 'TRAILING WHITESPACE'). Each of those then has a map of
+# file patterns (e.g. 'foo/*') to a set of specific line numbers for the
+# exception. The line numbers are optional; if missing the entire file
+# ignores the error.
+Ignorelist = Dict[str, Dict[str, Set[Optional[int]]]]
+
+# Define an arbitrary typevar
+T = TypeVar("T")
+
+
+logger: Optional[logging.Logger] = None
+
+
+def setup_logging(prefix: bool = False) -> None:
+    global logger
+    if logger is None:
+        logger = logging.getLogger(os.path.basename(os.path.splitext(__file__)[0]))
+        handler: logging.Handler = logging.StreamHandler(sys.stdout)
+        # Only add a handler if the parent logger is missing a handler
+        parent = logger.parent
+        assert isinstance(parent, logging.Logger)
+        if parent and len(parent.handlers) == 0:
+            handler = logging.StreamHandler(sys.stdout)
+            logger.addHandler(handler)
+    if prefix:
+        format = logging.BASIC_FORMAT
+    else:
+        format = "%(message)s"
+    formatter = logging.Formatter(format)
+    for handler in logger.handlers:
+        handler.setFormatter(formatter)
+    logger.setLevel(logging.DEBUG)
+
+
+setup_logging()
+
+
+ERROR_MSG = """You must fix all errors; for details on how to fix them, see
+https://web-platform-tests.org/writing-tests/lint-tool.html
+
+However, instead of fixing a particular error, it's sometimes
+OK to add a line to the lint.ignore file in the root of the
+web-platform-tests directory to make the lint tool ignore it.
+
+For example, to make the lint tool ignore all '%s'
+errors in the %s file,
+you could add the following line to the lint.ignore file.
+
+%s: %s"""
+
+
+def all_filesystem_paths(repo_root: Text, subdir: Optional[Text] = None) -> Iterable[Text]:
+    path_filter = PathFilter(repo_root.encode("utf8"),
+                             extras=[b".git/"])
+    if subdir:
+        expanded_path = subdir.encode("utf8")
+        subdir_str = expanded_path
+    else:
+        expanded_path = repo_root.encode("utf8")
+    for dirpath, dirnames, filenames in path_filter(walk(expanded_path)):
+        for filename, _ in filenames:
+            path = os.path.join(dirpath, filename)
+            if subdir:
+                path = os.path.join(subdir_str, path)
+            assert not os.path.isabs(path), path
+            yield path.decode("utf8")
+
+
+def _all_files_equal(paths: Iterable[Text]) -> bool:
+    """
+    Checks all the paths are files that are byte-for-byte identical
+
+    :param paths: the list of paths to compare
+    :returns: True if they are all identical
+    """
+    paths = list(paths)
+    if len(paths) < 2:
+        return True
+
+    first = paths.pop()
+    size = os.path.getsize(first)
+    if any(os.path.getsize(path) != size for path in paths):
+        return False
+
+    # Chunk this to avoid eating up memory and file descriptors
+    bufsize = 4096*4  # 16KB, a "reasonable" number of disk sectors
+    groupsize = 8  # Hypothesised to be large enough in the common case that everything fits in one group
+    with open(first, "rb") as first_f:
+        for start in range(0, len(paths), groupsize):
+            path_group = paths[start:start+groupsize]
+            first_f.seek(0)
+            try:
+                files = [open(x, "rb") for x in path_group]
+                for _ in range(0, size, bufsize):
+                    a = first_f.read(bufsize)
+                    for f in files:
+                        b = f.read(bufsize)
+                        if a != b:
+                            return False
+            finally:
+                for f in files:
+                    f.close()
+
+    return True
+
+
+def check_path_length(repo_root: Text, path: Text) -> List[rules.Error]:
+    if len(path) + 1 > 150:
+        return [rules.PathLength.error(path, (path, len(path) + 1))]
+    return []
+
+
+def check_file_type(repo_root: Text, path: Text) -> List[rules.Error]:
+    if os.path.islink(path):
+        return [rules.FileType.error(path, (path, "symlink"))]
+    return []
+
+
+def check_worker_collision(repo_root: Text, path: Text) -> List[rules.Error]:
+    endings = [(".any.html", ".any.js"),
+               (".any.worker.html", ".any.js"),
+               (".worker.html", ".worker.js")]
+    for path_ending, generated in endings:
+        if path.endswith(path_ending):
+            return [rules.WorkerCollision.error(path, (path_ending, generated))]
+    return []
+
+
+def check_gitignore_file(repo_root: Text, path: Text) -> List[rules.Error]:
+    if not path.endswith(".gitignore"):
+        return []
+
+    path_parts = path.split(os.path.sep)
+    if len(path_parts) == 1:
+        return []
+
+    if path_parts[-1] != ".gitignore":
+        return []
+
+    if (path_parts[0] in ["tools", "docs"] or
+        path_parts[:2] == ["resources", "webidl2"]):
+        return []
+
+    return [rules.GitIgnoreFile.error(path)]
+
+
+def check_mojom_js(repo_root: Text, path: Text) -> List[rules.Error]:
+    if path.endswith(".mojom.js"):
+        return [rules.MojomJSFile.error(path)]
+    return []
+
+
+def check_ahem_copy(repo_root: Text, path: Text) -> List[rules.Error]:
+    lpath = path.lower()
+    if "ahem" in lpath and lpath.endswith(".ttf"):
+        return [rules.AhemCopy.error(path)]
+    return []
+
+
+def check_tentative_directories(repo_root: Text, path: Text) -> List[rules.Error]:
+    path_parts = path.split(os.path.sep)
+    for directory in path_parts[:-1]:
+        if "tentative" in directory and directory != "tentative":
+            return [rules.TentativeDirectoryName.error(path)]
+    return []
+
+
+def check_git_ignore(repo_root: Text, paths: List[Text]) -> List[rules.Error]:
+    errors = []
+
+    with tempfile.TemporaryFile('w+', newline='') as f:
+        for path in paths:
+            f.write('%s\n' % os.path.join(repo_root, path))
+        f.seek(0)
+        try:
+            matches = subprocess.check_output(
+                ["git", "check-ignore", "--verbose", "--no-index", "--stdin"], stdin=f)
+            for match in matches.strip().split(b'\n'):
+                match_filter, path_bytes = match.split()
+                _, _, filter_string = match_filter.split(b':')
+                # If the matching filter reported by check-ignore is a special-case exception,
+                # that's fine. Otherwise, it requires a new special-case exception.
+                if filter_string[0:1] != b'!':
+                    path = path_bytes.decode("utf8")
+                    errors.append(rules.IgnoredPath.error(path, (path,)))
+        except subprocess.CalledProcessError:
+            # Nonzero return code means that no match exists.
+            pass
+    return errors
+
+
+drafts_csswg_re = re.compile(r"https?\:\/\/drafts\.csswg\.org\/([^/?#]+)")
+w3c_tr_re = re.compile(r"https?\:\/\/www\.w3c?\.org\/TR\/([^/?#]+)")
+w3c_dev_re = re.compile(r"https?\:\/\/dev\.w3c?\.org\/[^/?#]+\/([^/?#]+)")
+
+
+def check_unique_testharness_basenames(repo_root: Text, paths: List[Text]) -> List[rules.Error]:
+    """
+    Checks that all testharness files have unique basename paths.
+
+    The 'basename path' refers to the entire path excluding the extension. For
+    example, 'foo/bar/baz.html' and 'foo/bar/baz.xhtml' have the same basename
+    path, but 'foo/bar/baz.html' and 'foo/qux/baz.html' do not.
+
+    Testharness files with identical basenames have caused issues in downstream
+    infrastructure (see https://github.com/web-platform-tests/wpt/issues/7570),
+    and may cause confusion in general.
+
+    :param repo_root: the repository root
+    :param paths: list of all paths
+    :returns: a list of errors found in ``paths``
+    """
+
+    errors = []
+    file_dict = defaultdict(list)
+    for path in paths:
+        source_file = SourceFile(repo_root, path, "/")
+        if "testharness" not in source_file.possible_types:
+            continue
+        file_name, file_extension = os.path.splitext(path)
+        file_dict[file_name].append(file_extension)
+    for k, v in file_dict.items():
+        if len(v) == 1:
+            continue
+        context = (', '.join(v),)
+        for extension in v:
+            errors.append(rules.DuplicateBasenamePath.error(k + extension, context))
+    return errors
+
+
+def check_unique_case_insensitive_paths(repo_root: Text, paths: List[Text]) -> List[rules.Error]:
+    seen: Dict[Text, Text] = {}
+    errors = []
+    for path in paths:
+        lower_path = path.lower()
+        if lower_path in seen:
+            context = (seen[lower_path],)
+            errors.append(rules.DuplicatePathCaseInsensitive.error(path, context))
+        else:
+            seen[lower_path] = path
+    return errors
+
+
+def parse_ignorelist(f: IO[Text]) -> Tuple[Ignorelist, Set[Text]]:
+    """
+    Parse the ignorelist file given by `f`, and return the parsed structure.
+
+    :returns: a tuple of an Ignorelist and a set of files that are completely
+              skipped by the linter (i.e. have a '*' entry).
+    """
+
+    data: Ignorelist = defaultdict(lambda:defaultdict(set))
+    skipped_files: Set[Text] = set()
+
+    for line in f:
+        line = line.strip()
+        if not line or line.startswith("#"):
+            continue
+        parts = [item.strip() for item in line.split(":")]
+
+        if len(parts) == 2:
+            error_types_s, file_match = parts
+            line_number: Optional[int] = None
+        else:
+            error_types_s, file_match, line_number_s = parts
+            line_number = int(line_number_s)
+
+        error_types = {item.strip() for item in error_types_s.split(",")}
+        file_match = os.path.normcase(file_match)
+
+        if "*" in error_types:
+            skipped_files.add(file_match)
+        else:
+            for error_type in error_types:
+                data[error_type][file_match].add(line_number)
+
+    return data, skipped_files
+
+
+def filter_ignorelist_errors(data: Ignorelist, errors: Sequence[rules.Error]) -> List[rules.Error]:
+    """
+    Filter out those errors that are ignored in `data`.
+    """
+
+    if not errors:
+        return []
+
+    skipped = [False for item in range(len(errors))]
+
+    for i, (error_type, msg, path, line) in enumerate(errors):
+        normpath = os.path.normcase(path)
+        # Allow skipping all lint errors except the IGNORED PATH lint,
+        # which explains how to fix it correctly and shouldn't be skipped.
+        if error_type in data and error_type != "IGNORED PATH":
+            wl_files = data[error_type]
+            for file_match, allowed_lines in wl_files.items():
+                if None in allowed_lines or line in allowed_lines:
+                    if fnmatch.fnmatchcase(normpath, file_match):
+                        skipped[i] = True
+
+    return [item for i, item in enumerate(errors) if not skipped[i]]
+
+
+regexps = [item() for item in  # type: ignore
+           [rules.TrailingWhitespaceRegexp,
+            rules.TabsRegexp,
+            rules.CRRegexp,
+            rules.SetTimeoutRegexp,
+            rules.W3CTestOrgRegexp,
+            rules.WebPlatformTestRegexp,
+            rules.Webidl2Regexp,
+            rules.ConsoleRegexp,
+            rules.GenerateTestsRegexp,
+            rules.PrintRegexp,
+            rules.LayoutTestsRegexp,
+            rules.MissingDepsRegexp,
+            rules.SpecialPowersRegexp,
+            rules.AssertThrowsRegexp,
+            rules.PromiseRejectsRegexp,
+            rules.AssertPreconditionRegexp]]
+
+
+def check_regexp_line(repo_root: Text, path: Text, f: IO[bytes]) -> List[rules.Error]:
+    errors: List[rules.Error] = []
+
+    applicable_regexps = [regexp for regexp in regexps if regexp.applies(path)]
+
+    for i, line in enumerate(f):
+        for regexp in applicable_regexps:
+            if regexp.search(line):
+                errors.append((regexp.name, regexp.description, path, i+1))
+
+    return errors
+
+
+def check_parsed(repo_root: Text, path: Text, f: IO[bytes]) -> List[rules.Error]:
+    source_file = SourceFile(repo_root, path, "/", contents=f.read())
+
+    errors: List[rules.Error] = []
+
+    if path.startswith("css/"):
+        if (source_file.type != "support" and
+            not source_file.name_is_reference and
+            not source_file.name_is_tentative and
+            not source_file.name_is_crashtest and
+            not source_file.spec_links):
+            return [rules.MissingLink.error(path)]
+
+    if source_file.name_is_non_test:
+        return []
+
+    if source_file.markup_type is None:
+        return []
+
+    if source_file.root is None:
+        return [rules.ParseFailed.error(path)]
+
+    if source_file.type == "manual" and not source_file.name_is_manual:
+        errors.append(rules.ContentManual.error(path))
+
+    if source_file.type == "visual" and not source_file.name_is_visual:
+        errors.append(rules.ContentVisual.error(path))
+
+    about_blank_parts = urlsplit("about:blank")
+    for reftest_node in source_file.reftest_nodes:
+        href = reftest_node.attrib.get("href", "").strip(space_chars)
+        parts = urlsplit(href)
+
+        if parts == about_blank_parts:
+            continue
+
+        if (parts.scheme or parts.netloc):
+            errors.append(rules.AbsoluteUrlRef.error(path, (href,)))
+            continue
+
+        ref_url = urljoin(source_file.url, href)
+        ref_parts = urlsplit(ref_url)
+
+        if source_file.url == ref_url:
+            errors.append(rules.SameFileRef.error(path))
+            continue
+
+        assert ref_parts.path != ""
+
+        reference_file = os.path.join(repo_root, ref_parts.path[1:])
+        reference_rel = reftest_node.attrib.get("rel", "")
+
+        if not os.path.isfile(reference_file):
+            errors.append(rules.NonexistentRef.error(path,
+                                                     (reference_rel, href)))
+
+    if len(source_file.timeout_nodes) > 1:
+        errors.append(rules.MultipleTimeout.error(path))
+
+    for timeout_node in source_file.timeout_nodes:
+        timeout_value = timeout_node.attrib.get("content", "").lower()
+        if timeout_value != "long":
+            errors.append(rules.InvalidTimeout.error(path, (timeout_value,)))
+
+    required_elements: List[Text] = []
+
+    testharnessreport_nodes: List[ElementTree.Element] = []
+    if source_file.testharness_nodes:
+        test_type = source_file.manifest_items()[0]
+        if test_type not in ("testharness", "manual"):
+            errors.append(rules.TestharnessInOtherType.error(path, (test_type,)))
+        if len(source_file.testharness_nodes) > 1:
+            errors.append(rules.MultipleTestharness.error(path))
+
+        testharnessreport_nodes = source_file.root.findall(".//{http://www.w3.org/1999/xhtml}script[@src='/resources/testharnessreport.js']")
+        if not testharnessreport_nodes:
+            errors.append(rules.MissingTestharnessReport.error(path))
+        else:
+            if len(testharnessreport_nodes) > 1:
+                errors.append(rules.MultipleTestharnessReport.error(path))
+
+        for element in source_file.variant_nodes:
+            if "content" not in element.attrib:
+                errors.append(rules.VariantMissing.error(path))
+            else:
+                variant = element.attrib["content"]
+                if variant != "":
+                    if (variant[0] not in ("?", "#") or
+                        len(variant) == 1 or
+                        (variant[0] == "?" and variant[1] == "#")):
+                        errors.append(rules.MalformedVariant.error(path, (path,)))
+
+        required_elements.extend(key for key, value in {"testharness": True,
+                                                        "testharnessreport": len(testharnessreport_nodes) > 0,
+                                                        "timeout": len(source_file.timeout_nodes) > 0}.items()
+                                 if value)
+
+    testdriver_vendor_nodes: List[ElementTree.Element] = []
+    if source_file.testdriver_nodes:
+        if len(source_file.testdriver_nodes) > 1:
+            errors.append(rules.MultipleTestdriver.error(path))
+
+        testdriver_vendor_nodes = source_file.root.findall(".//{http://www.w3.org/1999/xhtml}script[@src='/resources/testdriver-vendor.js']")
+        if not testdriver_vendor_nodes:
+            errors.append(rules.MissingTestdriverVendor.error(path))
+        else:
+            if len(testdriver_vendor_nodes) > 1:
+                errors.append(rules.MultipleTestdriverVendor.error(path))
+
+        required_elements.append("testdriver")
+        if len(testdriver_vendor_nodes) > 0:
+            required_elements.append("testdriver-vendor")
+
+    if required_elements:
+        seen_elements = defaultdict(bool)
+
+        for elem in source_file.root.iter():
+            if source_file.timeout_nodes and elem == source_file.timeout_nodes[0]:
+                seen_elements["timeout"] = True
+                if seen_elements["testharness"]:
+                    errors.append(rules.LateTimeout.error(path))
+
+            elif source_file.testharness_nodes and elem == source_file.testharness_nodes[0]:
+                seen_elements["testharness"] = True
+
+            elif testharnessreport_nodes and elem == testharnessreport_nodes[0]:
+                seen_elements["testharnessreport"] = True
+                if not seen_elements["testharness"]:
+                    errors.append(rules.EarlyTestharnessReport.error(path))
+
+            elif source_file.testdriver_nodes and elem == source_file.testdriver_nodes[0]:
+                seen_elements["testdriver"] = True
+
+            elif testdriver_vendor_nodes and elem == testdriver_vendor_nodes[0]:
+                seen_elements["testdriver-vendor"] = True
+                if not seen_elements["testdriver"]:
+                    errors.append(rules.EarlyTestdriverVendor.error(path))
+
+            if all(seen_elements[name] for name in required_elements):
+                break
+
+    for element in source_file.root.findall(".//{http://www.w3.org/1999/xhtml}script[@src]"):
+        src = element.attrib["src"]
+
+        def incorrect_path(script: Text, src: Text) -> bool:
+            return (script == src or
+                ("/%s" % script in src and src != "/resources/%s" % script))
+
+        if incorrect_path("testharness.js", src):
+            errors.append(rules.TestharnessPath.error(path))
+
+        if incorrect_path("testharnessreport.js", src):
+            errors.append(rules.TestharnessReportPath.error(path))
+
+        if incorrect_path("testdriver.js", src):
+            errors.append(rules.TestdriverPath.error(path))
+
+        if incorrect_path("testdriver-vendor.js", src):
+            errors.append(rules.TestdriverVendorPath.error(path))
+
+        script_path = None
+        try:
+            script_path = urlsplit(urljoin(source_file.url, src)).path
+        except ValueError:
+            # This happens if the contents of src isn't something that looks like a URL to Python
+            pass
+        if (script_path == "/common/reftest-wait.js" and
+            "reftest-wait" not in source_file.root.attrib.get("class", "").split()):
+            errors.append(rules.MissingReftestWait.error(path))
+
+    return errors
+
+class ASTCheck(metaclass=abc.ABCMeta):
+    @abc.abstractproperty
+    def rule(self) -> Type[rules.Rule]:
+        pass
+
+    @abc.abstractmethod
+    def check(self, root: ast.AST) -> List[int]:
+        pass
+
+class OpenModeCheck(ASTCheck):
+    rule = rules.OpenNoMode
+
+    def check(self, root: ast.AST) -> List[int]:
+        errors = []
+        for node in ast.walk(root):
+            if isinstance(node, ast.Call):
+                if hasattr(node.func, "id") and node.func.id in ("open", "file"):
+                    if (len(node.args) < 2 and
+                        all(item.arg != "mode" for item in node.keywords)):
+                        errors.append(node.lineno)
+        return errors
+
+ast_checkers = [item() for item in [OpenModeCheck]]
+
+def check_python_ast(repo_root: Text, path: Text, f: IO[bytes]) -> List[rules.Error]:
+    if not path.endswith(".py"):
+        return []
+
+    try:
+        root = ast.parse(f.read())
+    except SyntaxError as e:
+        return [rules.ParseFailed.error(path, line_no=e.lineno)]
+
+    errors = []
+    for checker in ast_checkers:
+        for lineno in checker.check(root):
+            errors.append(checker.rule.error(path, line_no=lineno))
+    return errors
+
+
+broken_js_metadata = re.compile(br"//\s*META:")
+broken_python_metadata = re.compile(br"#\s*META:")
+
+
+def check_global_metadata(value: bytes) -> Iterable[Tuple[Type[rules.Rule], Tuple[Any, ...]]]:
+    global_values = {item.strip().decode("utf8") for item in value.split(b",") if item.strip()}
+
+    # TODO: this could check for duplicates and such
+    for global_value in global_values:
+        if not get_any_variants(global_value):
+            yield (rules.UnknownGlobalMetadata, ())
+
+
+def check_script_metadata(repo_root: Text, path: Text, f: IO[bytes]) -> List[rules.Error]:
+    if path.endswith((".worker.js", ".any.js")):
+        meta_re = js_meta_re
+        broken_metadata = broken_js_metadata
+    elif path.endswith(".py"):
+        meta_re = python_meta_re
+        broken_metadata = broken_python_metadata
+    else:
+        return []
+
+    done = False
+    errors = []
+    for idx, line in enumerate(f):
+        assert isinstance(line, bytes), line
+
+        m = meta_re.match(line)
+        if m:
+            key, value = m.groups()
+            if key == b"global":
+                for rule_class, context in check_global_metadata(value):
+                    errors.append(rule_class.error(path, context, idx + 1))
+            elif key == b"timeout":
+                if value != b"long":
+                    errors.append(rules.UnknownTimeoutMetadata.error(path,
+                                                                     line_no=idx + 1))
+            elif key not in (b"title", b"script", b"variant", b"quic"):
+                errors.append(rules.UnknownMetadata.error(path,
+                                                          line_no=idx + 1))
+        else:
+            done = True
+
+        if done:
+            if meta_re.match(line):
+                errors.append(rules.StrayMetadata.error(path, line_no=idx + 1))
+            elif meta_re.search(line):
+                errors.append(rules.IndentedMetadata.error(path,
+                                                           line_no=idx + 1))
+            elif broken_metadata.search(line):
+                errors.append(rules.BrokenMetadata.error(path, line_no=idx + 1))
+
+    return errors
+
+
+ahem_font_re = re.compile(br"font.*:.*ahem", flags=re.IGNORECASE)
+# Ahem can appear either in the global location or in the support
+# directory for legacy Mozilla imports
+ahem_stylesheet_re = re.compile(br"\/fonts\/ahem\.css|support\/ahem.css",
+                                flags=re.IGNORECASE)
+
+
+def check_ahem_system_font(repo_root: Text, path: Text, f: IO[bytes]) -> List[rules.Error]:
+    if not path.endswith((".html", ".htm", ".xht", ".xhtml")):
+        return []
+    contents = f.read()
+    errors = []
+    if ahem_font_re.search(contents) and not ahem_stylesheet_re.search(contents):
+        errors.append(rules.AhemSystemFont.error(path))
+    return errors
+
+
+def check_path(repo_root: Text, path: Text) -> List[rules.Error]:
+    """
+    Runs lints that check the file path.
+
+    :param repo_root: the repository root
+    :param path: the path of the file within the repository
+    :returns: a list of errors found in ``path``
+    """
+
+    errors = []
+    for path_fn in path_lints:
+        errors.extend(path_fn(repo_root, path))
+    return errors
+
+
+def check_all_paths(repo_root: Text, paths: List[Text]) -> List[rules.Error]:
+    """
+    Runs lints that check all paths globally.
+
+    :param repo_root: the repository root
+    :param paths: a list of all the paths within the repository
+    :returns: a list of errors found in ``f``
+    """
+
+    errors = []
+    for paths_fn in all_paths_lints:
+        errors.extend(paths_fn(repo_root, paths))
+    return errors
+
+
+def check_file_contents(repo_root: Text, path: Text, f: Optional[IO[bytes]] = None) -> List[rules.Error]:
+    """
+    Runs lints that check the file contents.
+
+    :param repo_root: the repository root
+    :param path: the path of the file within the repository
+    :param f: a file-like object with the file contents
+    :returns: a list of errors found in ``f``
+    """
+    if f is None:
+        f = open(os.path.join(repo_root, path), 'rb')
+    with f:
+        errors = []
+        for file_fn in file_lints:
+            errors.extend(file_fn(repo_root, path, f))
+            f.seek(0)
+        return errors
+
+
+def check_file_contents_apply(args: Tuple[Text, Text]) -> List[rules.Error]:
+    return check_file_contents(*args)
+
+
+def output_errors_text(log: Callable[[Any], None], errors: List[rules.Error]) -> None:
+    for error_type, description, path, line_number in errors:
+        pos_string = path
+        if line_number:
+            pos_string += ":%s" % line_number
+        log(f"{pos_string}: {description} ({error_type})")
+
+
+def output_errors_markdown(log: Callable[[Any], None], errors: List[rules.Error]) -> None:
+    if not errors:
+        return
+    heading = """Got lint errors:
+
+| Error Type | Position | Message |
+|------------|----------|---------|"""
+    for line in heading.split("\n"):
+        log(line)
+    for error_type, description, path, line_number in errors:
+        pos_string = path
+        if line_number:
+            pos_string += ":%s" % line_number
+        log(f"{error_type} | {pos_string} | {description} |")
+
+
+def output_errors_json(log: Callable[[Any], None], errors: List[rules.Error]) -> None:
+    for error_type, error, path, line_number in errors:
+        # We use 'print' rather than the log function to ensure that the output
+        # is valid JSON (e.g. with no logger preamble).
+        print(json.dumps({"path": path, "lineno": line_number,
+                          "rule": error_type, "message": error}))
+
+
+def output_errors_github_checks(outputter: GitHubChecksOutputter, errors: List[rules.Error], first_reported: bool) -> None:
+    """Output errors to the GitHub Checks output markdown format.
+
+    :param outputter: the GitHub Checks outputter
+    :param errors: a list of error tuples (error type, message, path, line number)
+    :param first_reported: True if these are the first reported errors
+    """
+    if first_reported:
+        outputter.output(
+            "\nChanges in this PR contain lint errors, listed below. These "
+            "errors must either be fixed or added to the list of ignored "
+            "errors; see [the documentation]("
+            "https://web-platform-tests.org/writing-tests/lint-tool.html). "
+            "For help, please tag `@web-platform-tests/wpt-core-team` in a "
+            "comment.\n")
+        outputter.output("```")
+    output_errors_text(outputter.output, errors)
+
+
+def output_error_count(error_count: Dict[Text, int]) -> None:
+    if not error_count:
+        return
+
+    assert logger is not None
+    by_type = " ".join("%s: %d" % item for item in error_count.items())
+    count = sum(error_count.values())
+    logger.info("")
+    if count == 1:
+        logger.info(f"There was 1 error ({by_type})")
+    else:
+        logger.info("There were %d errors (%s)" % (count, by_type))
+
+
+def changed_files(wpt_root: Text) -> List[Text]:
+    revish = testfiles.get_revish(revish=None)
+    changed, _ = testfiles.files_changed(revish, None, include_uncommitted=True, include_new=True)
+    return [os.path.relpath(item, wpt_root) for item in changed]
+
+
+def lint_paths(kwargs: Dict[Text, Any], wpt_root: Text) -> List[Text]:
+    if kwargs.get("paths"):
+        paths = []
+        for path in kwargs.get("paths", []):
+            if os.path.isdir(path):
+                path_dir = list(all_filesystem_paths(wpt_root, path))
+                paths.extend(path_dir)
+            elif os.path.isfile(path):
+                paths.append(os.path.relpath(os.path.abspath(path), wpt_root))
+    elif kwargs["all"]:
+        paths = list(all_filesystem_paths(wpt_root))
+    elif kwargs["paths_file"]:
+        paths = []
+        with open(kwargs["paths_file"], 'r', newline='') as f:
+            for line in f.readlines():
+                path = line.strip()
+                if os.path.isdir(path):
+                    path_dir = list(all_filesystem_paths(wpt_root, path))
+                    paths.extend(path_dir)
+                elif os.path.isfile(path):
+                    paths.append(os.path.relpath(os.path.abspath(path), wpt_root))
+    else:
+        changed_paths = changed_files(wpt_root)
+        force_all = False
+        for path in changed_paths:
+            path = path.replace(os.path.sep, "/")
+            if path == "lint.ignore" or path.startswith("tools/lint/"):
+                force_all = True
+                break
+        paths = (list(changed_paths) if not force_all
+                 else list(all_filesystem_paths(wpt_root)))
+
+    return paths
+
+
+def create_parser() -> argparse.ArgumentParser:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("paths", nargs="*",
+                        help="List of paths to lint")
+    parser.add_argument("--json", action="store_true",
+                        help="Output machine-readable JSON format")
+    parser.add_argument("--markdown", action="store_true",
+                        help="Output markdown")
+    parser.add_argument("--repo-root", type=str,
+                        help="The WPT directory. Use this "
+                        "option if the lint script exists outside the repository")
+    parser.add_argument("--ignore-glob", type=str, action="append",
+                        help="Additional file glob to ignore (repeat to add more). "
+                        "Globs are matched against paths relative to REPO_ROOT "
+                        "using fnmatch, except that path separators are normalized.")
+    parser.add_argument("--all", action="store_true", help="If no paths are passed, try to lint the whole "
+                        "working directory, not just files that changed")
+    parser.add_argument("--github-checks-text-file", type=str,
+                        help="Path to GitHub checks output file for Taskcluster runs")
+    parser.add_argument("-j", "--jobs", type=int, default=0,
+                        help="Level to parallelism to use (defaults to 0, which detects the number of CPUs)")
+    parser.add_argument("--paths-file", help="File containing a list of files to lint, one per line")
+    return parser
+
+
+def main(**kwargs: Any) -> int:
+
+    assert logger is not None
+    if kwargs.get("json") and kwargs.get("markdown"):
+        logger.critical("Cannot specify --json and --markdown")
+        sys.exit(2)
+
+    repo_root = kwargs.get('repo_root') or localpaths.repo_root
+    output_format = {(True, False): "json",
+                     (False, True): "markdown",
+                     (False, False): "normal"}[(kwargs.get("json", False),
+                                                kwargs.get("markdown", False))]
+
+    if output_format == "markdown":
+        setup_logging(True)
+
+    paths = lint_paths(kwargs, repo_root)
+
+    ignore_glob = kwargs.get("ignore_glob", [])
+
+    github_checks_outputter = get_gh_checks_outputter(kwargs["github_checks_text_file"])
+
+    jobs = kwargs.get("jobs", 0)
+
+    return lint(repo_root, paths, output_format, ignore_glob, github_checks_outputter, jobs)
+
+
+# best experimental guess at a decent cut-off for using the parallel path
+MIN_FILES_FOR_PARALLEL = 80
+
+
+def lint(repo_root: Text,
+         paths: List[Text],
+         output_format: Text,
+         ignore_glob: Optional[List[Text]] = None,
+         github_checks_outputter: Optional[GitHubChecksOutputter] = None,
+         jobs: int = 0) -> int:
+    error_count: Dict[Text, int] = defaultdict(int)
+    last = None
+
+    if jobs == 0:
+        jobs = multiprocessing.cpu_count()
+        if sys.platform == 'win32':
+            # Using too many child processes in Python 3 hits either hangs or a
+            # ValueError exception, and, has diminishing returns. Clamp to 56 to
+            # give margin for error.
+            jobs = min(jobs, 56)
+
+    with open(os.path.join(repo_root, "lint.ignore")) as f:
+        ignorelist, skipped_files = parse_ignorelist(f)
+
+    if ignore_glob:
+        skipped_files |= set(ignore_glob)
+
+    output_errors = {"json": output_errors_json,
+                     "markdown": output_errors_markdown,
+                     "normal": output_errors_text}[output_format]
+
+    def process_errors(errors: List[rules.Error]) -> Optional[Tuple[Text, Text]]:
+        """
+        Filters and prints the errors, and updates the ``error_count`` object.
+
+        :param errors: a list of error tuples (error type, message, path, line number)
+        :returns: ``None`` if there were no errors, or
+                  a tuple of the error type and the path otherwise
+        """
+
+        errors = filter_ignorelist_errors(ignorelist, errors)
+        if not errors:
+            return None
+
+        assert logger is not None
+        output_errors(logger.error, errors)
+
+        if github_checks_outputter:
+            first_output = len(error_count) == 0
+            output_errors_github_checks(github_checks_outputter, errors, first_output)
+
+        for error_type, error, path, line in errors:
+            error_count[error_type] += 1
+
+        return (errors[-1][0], path)
+
+    to_check_content = []
+    skip = set()
+
+    for path in paths:
+        abs_path = os.path.join(repo_root, path)
+        if not os.path.exists(abs_path):
+            skip.add(path)
+            continue
+
+        if any(fnmatch.fnmatch(path, file_match) for file_match in skipped_files):
+            skip.add(path)
+            continue
+
+        errors = check_path(repo_root, path)
+        last = process_errors(errors) or last
+
+        if not os.path.isdir(abs_path):
+            to_check_content.append((repo_root, path))
+
+    paths = [p for p in paths if p not in skip]
+
+    if jobs > 1 and len(to_check_content) >= MIN_FILES_FOR_PARALLEL:
+        pool = multiprocessing.Pool(jobs)
+        # submit this job first, as it's the longest running
+        all_paths_result = pool.apply_async(check_all_paths, (repo_root, paths))
+        # each item tends to be quick, so pass things in large chunks to avoid too much IPC overhead
+        errors_it = pool.imap_unordered(check_file_contents_apply, to_check_content, chunksize=40)
+        pool.close()
+        for errors in errors_it:
+            last = process_errors(errors) or last
+
+        errors = all_paths_result.get()
+        pool.join()
+        last = process_errors(errors) or last
+    else:
+        for item in to_check_content:
+            errors = check_file_contents(*item)
+            last = process_errors(errors) or last
+
+        errors = check_all_paths(repo_root, paths)
+        last = process_errors(errors) or last
+
+    if output_format in ("normal", "markdown"):
+        output_error_count(error_count)
+        if error_count:
+            assert last is not None
+            assert logger is not None
+            for line in (ERROR_MSG % (last[0], last[1], last[0], last[1])).split("\n"):
+                logger.info(line)
+
+    if error_count and github_checks_outputter:
+        github_checks_outputter.output("```")
+
+    return sum(error_count.values())
+
+
+path_lints = [check_file_type, check_path_length, check_worker_collision, check_ahem_copy,
+              check_mojom_js, check_tentative_directories, check_gitignore_file]
+all_paths_lints = [check_unique_testharness_basenames,
+                   check_unique_case_insensitive_paths]
+file_lints = [check_regexp_line, check_parsed, check_python_ast, check_script_metadata,
+              check_ahem_system_font]
+
+# Don't break users of the lint that don't have git installed.
+try:
+    subprocess.check_output(["git", "--version"])
+    all_paths_lints += [check_git_ignore]
+except (subprocess.CalledProcessError, FileNotFoundError):
+    print('No git present; skipping .gitignore lint.')
+
+if __name__ == "__main__":
+    args = create_parser().parse_args()
+    error_count = main(**vars(args))
+    if error_count > 0:
+        sys.exit(1)