Merging upstream version 2.8.2.

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

24 files changed, 332 insertions, 92 deletions

diff --git a/pre_commit/clientlib.py b/pre_commit/clientlib.py
index 8dfa947..87679bf 100644
--- a/pre_commit/clientlib.py
+++ b/pre_commit/clientlib.py
@@ -13,7 +13,7 @@ from identify.identify import ALL_TAGS
 
 import pre_commit.constants as C
 from pre_commit.color import add_color_option
-from pre_commit.error_handler import FatalError
+from pre_commit.errors import FatalError
 from pre_commit.languages.all import all_languages
 from pre_commit.logging_handler import logging_handler
 from pre_commit.util import parse_version
diff --git a/pre_commit/commands/install_uninstall.py b/pre_commit/commands/install_uninstall.py
index 85fa53c..684b598 100644
--- a/pre_commit/commands/install_uninstall.py
+++ b/pre_commit/commands/install_uninstall.py
@@ -55,7 +55,7 @@ def is_our_script(filename: str) -> bool:
 
 def shebang() -> str:
     if sys.platform == 'win32':
-        py = SYS_EXE
+        py, _ = os.path.splitext(SYS_EXE)
     else:
         exe_choices = [
             f'python{sys.version_info[0]}.{sys.version_info[1]}',
diff --git a/pre_commit/commands/run.py b/pre_commit/commands/run.py
index 1f28c8c..0d335e2 100644
--- a/pre_commit/commands/run.py
+++ b/pre_commit/commands/run.py
@@ -11,6 +11,7 @@ from typing import Any
 from typing import Collection
 from typing import Dict
 from typing import List
+from typing import MutableMapping
 from typing import Sequence
 from typing import Set
 from typing import Tuple
@@ -28,7 +29,6 @@ from pre_commit.repository import install_hook_envs
 from pre_commit.staged_files_only import staged_files_only
 from pre_commit.store import Store
 from pre_commit.util import cmd_output_b
-from pre_commit.util import EnvironT
 
 
 logger = logging.getLogger('pre_commit')
@@ -116,7 +116,7 @@ class Classifier:
         return Classifier(filenames)
 
 
-def _get_skips(environ: EnvironT) -> Set[str]:
+def _get_skips(environ: MutableMapping[str, str]) -> Set[str]:
     skips = environ.get('SKIP', '')
     return {skip.strip() for skip in skips.split(',') if skip.strip()}
 
@@ -258,7 +258,7 @@ def _run_hooks(
         config: Dict[str, Any],
         hooks: Sequence[Hook],
         args: argparse.Namespace,
-        environ: EnvironT,
+        environ: MutableMapping[str, str],
 ) -> int:
     """Actually run the hooks."""
     skips = _get_skips(environ)
@@ -315,7 +315,7 @@ def run(
         config_file: str,
         store: Store,
         args: argparse.Namespace,
-        environ: EnvironT = os.environ,
+        environ: MutableMapping[str, str] = os.environ,
 ) -> int:
     stash = not args.all_files and not args.files
 
diff --git a/pre_commit/commands/sample_config.py b/pre_commit/commands/sample_config.py
index d435faa..64617c3 100644
--- a/pre_commit/commands/sample_config.py
+++ b/pre_commit/commands/sample_config.py
@@ -7,7 +7,7 @@ SAMPLE_CONFIG = '''\
 # See https://pre-commit.com/hooks.html for more hooks
 repos:
 -   repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v2.4.0
+    rev: v3.2.0
     hooks:
     -   id: trailing-whitespace
     -   id: end-of-file-fixer
diff --git a/pre_commit/envcontext.py b/pre_commit/envcontext.py
index 16d3d15..4ab0d8c 100644
--- a/pre_commit/envcontext.py
+++ b/pre_commit/envcontext.py
@@ -2,13 +2,12 @@ import contextlib
 import enum
 import os
 from typing import Generator
+from typing import MutableMapping
 from typing import NamedTuple
 from typing import Optional
 from typing import Tuple
 from typing import Union
 
-from pre_commit.util import EnvironT
-
 
 class _Unset(enum.Enum):
     UNSET = 1
@@ -27,7 +26,7 @@ ValueT = Union[str, _Unset, SubstitutionT]
 PatchesT = Tuple[Tuple[str, ValueT], ...]
 
 
-def format_env(parts: SubstitutionT, env: EnvironT) -> str:
+def format_env(parts: SubstitutionT, env: MutableMapping[str, str]) -> str:
     return ''.join(
         env.get(part.name, part.default) if isinstance(part, Var) else part
         for part in parts
@@ -37,7 +36,7 @@ def format_env(parts: SubstitutionT, env: EnvironT) -> str:
 @contextlib.contextmanager
 def envcontext(
         patch: PatchesT,
-        _env: Optional[EnvironT] = None,
+        _env: Optional[MutableMapping[str, str]] = None,
 ) -> Generator[None, None, None]:
     """In this context, `os.environ` is modified according to `patch`.
 
@@ -50,7 +49,7 @@ def envcontext(
               replaced with the previous environment
     """
     env = os.environ if _env is None else _env
-    before = env.copy()
+    before = dict(env)
 
     for k, v in patch:
         if v is UNSET:
diff --git a/pre_commit/error_handler.py b/pre_commit/error_handler.py
index 13d78cb..023dd35 100644
--- a/pre_commit/error_handler.py
+++ b/pre_commit/error_handler.py
@@ -7,15 +7,17 @@ from typing import Generator
 
 import pre_commit.constants as C
 from pre_commit import output
+from pre_commit.errors import FatalError
 from pre_commit.store import Store
 from pre_commit.util import force_bytes
 
 
-class FatalError(RuntimeError):
-    pass
-
-
-def _log_and_exit(msg: str, exc: BaseException, formatted: str) -> None:
+def _log_and_exit(
+    msg: str,
+    ret_code: int,
+    exc: BaseException,
+    formatted: str,
+) -> None:
     error_msg = f'{msg}: {type(exc).__name__}: '.encode() + force_bytes(exc)
     output.write_line_b(error_msg)
 
@@ -52,9 +54,9 @@ def _log_and_exit(msg: str, exc: BaseException, formatted: str) -> None:
         _log_line('```')
         _log_line()
         _log_line('```')
-        _log_line(formatted)
+        _log_line(formatted.rstrip())
         _log_line('```')
-    raise SystemExit(1)
+    raise SystemExit(ret_code)
 
 
 @contextlib.contextmanager
@@ -63,9 +65,9 @@ def error_handler() -> Generator[None, None, None]:
         yield
     except (Exception, KeyboardInterrupt) as e:
         if isinstance(e, FatalError):
-            msg = 'An error has occurred'
+            msg, ret_code = 'An error has occurred', 1
         elif isinstance(e, KeyboardInterrupt):
-            msg = 'Interrupted (^C)'
+            msg, ret_code = 'Interrupted (^C)', 130
         else:
-            msg = 'An unexpected error has occurred'
-        _log_and_exit(msg, e, traceback.format_exc())
+            msg, ret_code = 'An unexpected error has occurred', 3
+        _log_and_exit(msg, ret_code, e, traceback.format_exc())
diff --git a/pre_commit/errors.py b/pre_commit/errors.py
new file mode 100644
index 0000000..f84d3f1
--- /dev/null
+++ b/pre_commit/errors.py
@@ -0,0 +1,2 @@
+class FatalError(RuntimeError):
+    pass
diff --git a/pre_commit/git.py b/pre_commit/git.py
index 576bef8..13ba664 100644
--- a/pre_commit/git.py
+++ b/pre_commit/git.py
@@ -3,12 +3,14 @@ import os.path
 import sys
 from typing import Dict
 from typing import List
+from typing import MutableMapping
 from typing import Optional
 from typing import Set
 
+from pre_commit.errors import FatalError
+from pre_commit.util import CalledProcessError
 from pre_commit.util import cmd_output
 from pre_commit.util import cmd_output_b
-from pre_commit.util import EnvironT
 
 
 logger = logging.getLogger(__name__)
@@ -22,7 +24,9 @@ def zsplit(s: str) -> List[str]:
         return []
 
 
-def no_git_env(_env: Optional[EnvironT] = None) -> Dict[str, str]:
+def no_git_env(
+        _env: Optional[MutableMapping[str, str]] = None,
+) -> Dict[str, str]:
     # Too many bugs dealing with environment variables and GIT:
     # https://github.com/pre-commit/pre-commit/issues/300
     # In git 2.6.3 (maybe others), git exports GIT_WORK_TREE while running
@@ -43,7 +47,21 @@ def no_git_env(_env: Optional[EnvironT] = None) -> Dict[str, str]:
 
 
 def get_root() -> str:
-    return cmd_output('git', 'rev-parse', '--show-toplevel')[1].strip()
+    try:
+        root = cmd_output('git', 'rev-parse', '--show-toplevel')[1].strip()
+    except CalledProcessError:
+        raise FatalError(
+            'git failed. Is it installed, and are you in a Git repository '
+            'directory?',
+        )
+    else:
+        if root == '':  # pragma: no cover (old git)
+            raise FatalError(
+                'git toplevel unexpectedly empty! make sure you are not '
+                'inside the `.git` directory of your repository.',
+            )
+        else:
+            return root
 
 
 def get_git_dir(git_root: str = '.') -> str:
@@ -181,7 +199,7 @@ def check_for_cygwin_mismatch() -> None:
     """See https://github.com/pre-commit/pre-commit/issues/354"""
     if sys.platform in ('cygwin', 'win32'):  # pragma: no cover (windows)
         is_cygwin_python = sys.platform == 'cygwin'
-        toplevel = cmd_output('git', 'rev-parse', '--show-toplevel')[1]
+        toplevel = get_root()
         is_cygwin_git = toplevel.startswith('/')
 
         if is_cygwin_python ^ is_cygwin_git:
diff --git a/pre_commit/languages/all.py b/pre_commit/languages/all.py
index 5609631..9c2e59d 100644
--- a/pre_commit/languages/all.py
+++ b/pre_commit/languages/all.py
@@ -6,8 +6,10 @@ from typing import Tuple
 
 from pre_commit.hook import Hook
 from pre_commit.languages import conda
+from pre_commit.languages import coursier
 from pre_commit.languages import docker
 from pre_commit.languages import docker_image
+from pre_commit.languages import dotnet
 from pre_commit.languages import fail
 from pre_commit.languages import golang
 from pre_commit.languages import node
@@ -40,8 +42,10 @@ class Language(NamedTuple):
 languages = {
     # BEGIN GENERATED (testing/gen-languages-all)
     'conda': Language(name='conda', ENVIRONMENT_DIR=conda.ENVIRONMENT_DIR, get_default_version=conda.get_default_version, healthy=conda.healthy, install_environment=conda.install_environment, run_hook=conda.run_hook),  # noqa: E501
+    'coursier': Language(name='coursier', ENVIRONMENT_DIR=coursier.ENVIRONMENT_DIR, get_default_version=coursier.get_default_version, healthy=coursier.healthy, install_environment=coursier.install_environment, run_hook=coursier.run_hook),  # noqa: E501
     'docker': Language(name='docker', ENVIRONMENT_DIR=docker.ENVIRONMENT_DIR, get_default_version=docker.get_default_version, healthy=docker.healthy, install_environment=docker.install_environment, run_hook=docker.run_hook),  # noqa: E501
     'docker_image': Language(name='docker_image', ENVIRONMENT_DIR=docker_image.ENVIRONMENT_DIR, get_default_version=docker_image.get_default_version, healthy=docker_image.healthy, install_environment=docker_image.install_environment, run_hook=docker_image.run_hook),  # noqa: E501
+    'dotnet': Language(name='dotnet', ENVIRONMENT_DIR=dotnet.ENVIRONMENT_DIR, get_default_version=dotnet.get_default_version, healthy=dotnet.healthy, install_environment=dotnet.install_environment, run_hook=dotnet.run_hook),  # noqa: E501
     'fail': Language(name='fail', ENVIRONMENT_DIR=fail.ENVIRONMENT_DIR, get_default_version=fail.get_default_version, healthy=fail.healthy, install_environment=fail.install_environment, run_hook=fail.run_hook),  # noqa: E501
     'golang': Language(name='golang', ENVIRONMENT_DIR=golang.ENVIRONMENT_DIR, get_default_version=golang.get_default_version, healthy=golang.healthy, install_environment=golang.install_environment, run_hook=golang.run_hook),  # noqa: E501
     'node': Language(name='node', ENVIRONMENT_DIR=node.ENVIRONMENT_DIR, get_default_version=node.get_default_version, healthy=node.healthy, install_environment=node.install_environment, run_hook=node.run_hook),  # noqa: E501
diff --git a/pre_commit/languages/conda.py b/pre_commit/languages/conda.py
index 071757a..d634e49 100644
--- a/pre_commit/languages/conda.py
+++ b/pre_commit/languages/conda.py
@@ -77,7 +77,7 @@ def run_hook(
         color: bool,
 ) -> Tuple[int, bytes]:
     # TODO: Some rare commands need to be run using `conda run` but mostly we
-    #       can run them withot which is much quicker and produces a better
+    #       can run them without which is much quicker and produces a better
     #       output.
     # cmd = ('conda', 'run', '-p', env_dir) + hook.cmd
     with in_env(hook.prefix, hook.language_version):
diff --git a/pre_commit/languages/coursier.py b/pre_commit/languages/coursier.py
new file mode 100644
index 0000000..2841467
--- /dev/null
+++ b/pre_commit/languages/coursier.py
@@ -0,0 +1,71 @@
+import contextlib
+import os
+from typing import Generator
+from typing import Sequence
+from typing import Tuple
+
+from pre_commit.envcontext import envcontext
+from pre_commit.envcontext import PatchesT
+from pre_commit.envcontext import Var
+from pre_commit.hook import Hook
+from pre_commit.languages import helpers
+from pre_commit.prefix import Prefix
+from pre_commit.util import clean_path_on_failure
+
+ENVIRONMENT_DIR = 'coursier'
+
+get_default_version = helpers.basic_get_default_version
+healthy = helpers.basic_healthy
+
+
+def install_environment(
+        prefix: Prefix,
+        version: str,
+        additional_dependencies: Sequence[str],
+) -> None:   # pragma: win32 no cover
+    helpers.assert_version_default('coursier', version)
+    helpers.assert_no_additional_deps('coursier', additional_dependencies)
+
+    envdir = prefix.path(helpers.environment_dir(ENVIRONMENT_DIR, version))
+    channel = prefix.path('.pre-commit-channel')
+    with clean_path_on_failure(envdir):
+        for app_descriptor in os.listdir(channel):
+            _, app_file = os.path.split(app_descriptor)
+            app, _ = os.path.splitext(app_file)
+            helpers.run_setup_cmd(
+                prefix,
+                (
+                    'cs',
+                    'install',
+                    '--default-channels=false',
+                    f'--channel={channel}',
+                    app,
+                    f'--dir={envdir}',
+                ),
+            )
+
+
+def get_env_patch(target_dir: str) -> PatchesT:   # pragma: win32 no cover
+    return (
+        ('PATH', (target_dir, os.pathsep, Var('PATH'))),
+    )
+
+
+@contextlib.contextmanager
+def in_env(
+        prefix: Prefix,
+) -> Generator[None, None, None]:   # pragma: win32 no cover
+    target_dir = prefix.path(
+        helpers.environment_dir(ENVIRONMENT_DIR, get_default_version()),
+    )
+    with envcontext(get_env_patch(target_dir)):
+        yield
+
+
+def run_hook(
+        hook: Hook,
+        file_args: Sequence[str],
+        color: bool,
+) -> Tuple[int, bytes]:   # pragma: win32 no cover
+    with in_env(hook.prefix):
+        return helpers.run_xargs(hook, hook.cmd, file_args, color=color)
diff --git a/pre_commit/languages/docker.py b/pre_commit/languages/docker.py
index 9c13119..9d30568 100644
--- a/pre_commit/languages/docker.py
+++ b/pre_commit/languages/docker.py
@@ -87,9 +87,8 @@ def run_hook(
     # automated cleanup of docker images.
     build_docker_image(hook.prefix, pull=False)
 
-    hook_cmd = hook.cmd
-    entry_exe, cmd_rest = hook.cmd[0], hook_cmd[1:]
+    entry_exe, *cmd_rest = hook.cmd
 
     entry_tag = ('--entrypoint', entry_exe, docker_tag(hook.prefix))
-    cmd = docker_cmd() + entry_tag + cmd_rest
+    cmd = (*docker_cmd(), *entry_tag, *cmd_rest)
     return helpers.run_xargs(hook, cmd, file_args, color=color)
diff --git a/pre_commit/languages/dotnet.py b/pre_commit/languages/dotnet.py
new file mode 100644
index 0000000..a8abc86
--- /dev/null
+++ b/pre_commit/languages/dotnet.py
@@ -0,0 +1,90 @@
+import contextlib
+import os.path
+from typing import Generator
+from typing import Sequence
+from typing import Tuple
+
+import pre_commit.constants as C
+from pre_commit.envcontext import envcontext
+from pre_commit.envcontext import PatchesT
+from pre_commit.envcontext import Var
+from pre_commit.hook import Hook
+from pre_commit.languages import helpers
+from pre_commit.prefix import Prefix
+from pre_commit.util import clean_path_on_failure
+from pre_commit.util import rmtree
+
+ENVIRONMENT_DIR = 'dotnetenv'
+BIN_DIR = 'bin'
+
+get_default_version = helpers.basic_get_default_version
+healthy = helpers.basic_healthy
+
+
+def get_env_patch(venv: str) -> PatchesT:
+    return (
+        ('PATH', (os.path.join(venv, BIN_DIR), os.pathsep, Var('PATH'))),
+    )
+
+
+@contextlib.contextmanager
+def in_env(prefix: Prefix) -> Generator[None, None, None]:
+    directory = helpers.environment_dir(ENVIRONMENT_DIR, C.DEFAULT)
+    envdir = prefix.path(directory)
+    with envcontext(get_env_patch(envdir)):
+        yield
+
+
+def install_environment(
+        prefix: Prefix,
+        version: str,
+        additional_dependencies: Sequence[str],
+) -> None:
+    helpers.assert_version_default('dotnet', version)
+    helpers.assert_no_additional_deps('dotnet', additional_dependencies)
+
+    envdir = prefix.path(helpers.environment_dir(ENVIRONMENT_DIR, version))
+    with clean_path_on_failure(envdir):
+        build_dir = 'pre-commit-build'
+
+        # Build & pack nupkg file
+        helpers.run_setup_cmd(
+            prefix,
+            (
+                'dotnet', 'pack',
+                '--configuration', 'Release',
+                '--output', build_dir,
+            ),
+        )
+
+        # Determine tool from the packaged file <tool_name>.<version>.nupkg
+        build_outputs = os.listdir(os.path.join(prefix.prefix_dir, build_dir))
+        if len(build_outputs) != 1:
+            raise NotImplementedError(
+                f"Can't handle multiple build outputs. Got {build_outputs}",
+            )
+        tool_name = build_outputs[0].split('.')[0]
+
+        # Install to bin dir
+        helpers.run_setup_cmd(
+            prefix,
+            (
+                'dotnet', 'tool', 'install',
+                '--tool-path', os.path.join(envdir, BIN_DIR),
+                '--add-source', build_dir,
+                tool_name,
+            ),
+        )
+
+        # Cleanup build output
+        for d in ('bin', 'obj', build_dir):
+            rmtree(prefix.path(d))
+
+
+def run_hook(
+        hook: Hook,
+        file_args: Sequence[str],
+        color: bool,
+) -> Tuple[int, bytes]:
+    with in_env(hook.prefix):
+        return helpers.run_xargs(hook, hook.cmd, file_args, color=color)
diff --git a/pre_commit/languages/helpers.py b/pre_commit/languages/helpers.py
index 01c65ab..29138fd 100644
--- a/pre_commit/languages/helpers.py
+++ b/pre_commit/languages/helpers.py
@@ -1,6 +1,7 @@
 import multiprocessing
 import os
 import random
+import re
 from typing import Any
 from typing import List
 from typing import Optional
@@ -10,6 +11,7 @@ from typing import Tuple
 from typing import TYPE_CHECKING
 
 import pre_commit.constants as C
+from pre_commit import parse_shebang
 from pre_commit.hook import Hook
 from pre_commit.prefix import Prefix
 from pre_commit.util import cmd_output_b
@@ -20,6 +22,31 @@ if TYPE_CHECKING:
 
 FIXED_RANDOM_SEED = 1542676187
 
+SHIMS_RE = re.compile(r'[/\\]shims[/\\]')
+
+
+def exe_exists(exe: str) -> bool:
+    found = parse_shebang.find_executable(exe)
+    if found is None:  # exe exists
+        return False
+
+    homedir = os.path.expanduser('~')
+    try:
+        common: Optional[str] = os.path.commonpath((found, homedir))
+    except ValueError:  # on windows, different drives raises ValueError
+        common = None
+
+    return (
+        # it is not in a /shims/ directory
+        not SHIMS_RE.search(found) and
+        (
+            # the homedir is / (docker, service user, etc.)
+            os.path.dirname(homedir) == homedir or
+            # the exe is not contained in the home directory
+            common != homedir
+        )
+    )
+
 
 def run_setup_cmd(prefix: Prefix, cmd: Tuple[str, ...]) -> None:
     cmd_output_b(*cmd, cwd=prefix.prefix_dir)
diff --git a/pre_commit/languages/node.py b/pre_commit/languages/node.py
index d99e6f2..8dc4e8b 100644
--- a/pre_commit/languages/node.py
+++ b/pre_commit/languages/node.py
@@ -7,7 +7,6 @@ from typing import Sequence
 from typing import Tuple
 
 import pre_commit.constants as C
-from pre_commit import parse_shebang
 from pre_commit.envcontext import envcontext
 from pre_commit.envcontext import PatchesT
 from pre_commit.envcontext import UNSET
@@ -19,9 +18,9 @@ from pre_commit.prefix import Prefix
 from pre_commit.util import clean_path_on_failure
 from pre_commit.util import cmd_output
 from pre_commit.util import cmd_output_b
+from pre_commit.util import rmtree
 
 ENVIRONMENT_DIR = 'node_env'
-healthy = helpers.basic_healthy
 
 
 @functools.lru_cache(maxsize=1)
@@ -31,7 +30,7 @@ def get_default_version() -> str:
         return C.DEFAULT
     # if node is already installed, we can save a bunch of setup time by
     # using the installed version
-    elif all(parse_shebang.find_executable(exe) for exe in ('node', 'npm')):
+    elif all(helpers.exe_exists(exe) for exe in ('node', 'npm')):
         return 'system'
     else:
         return C.DEFAULT
@@ -73,6 +72,12 @@ def in_env(
         yield
 
 
+def healthy(prefix: Prefix, language_version: str) -> bool:
+    with in_env(prefix, language_version):
+        retcode, _, _ = cmd_output_b('node', '--version', retcode=None)
+        return retcode == 0
+
+
 def install_environment(
         prefix: Prefix, version: str, additional_dependencies: Sequence[str],
 ) -> None:
@@ -94,11 +99,23 @@ def install_environment(
         with in_env(prefix, version):
             # https://npm.community/t/npm-install-g-git-vs-git-clone-cd-npm-install-g/5449
             # install as if we installed from git
-            helpers.run_setup_cmd(prefix, ('npm', 'install'))
-            helpers.run_setup_cmd(
-                prefix,
-                ('npm', 'install', '-g', '.', *additional_dependencies),
+
+            local_install_cmd = (
+                'npm', 'install', '--dev', '--prod',
+                '--ignore-prepublish', '--no-progress', '--no-save',
             )
+            helpers.run_setup_cmd(prefix, local_install_cmd)
+
+            _, pkg, _ = cmd_output('npm', 'pack', cwd=prefix.prefix_dir)
+            pkg = prefix.path(pkg.strip())
+
+            install = ('npm', 'install', '-g', pkg, *additional_dependencies)
+            helpers.run_setup_cmd(prefix, install)
+
+            # clean these up after installation
+            if prefix.exists('node_modules'):  # pragma: win32 no cover
+                rmtree(prefix.path('node_modules'))
+            os.remove(pkg)
 
 
 def run_hook(
diff --git a/pre_commit/languages/pygrep.py b/pre_commit/languages/pygrep.py
index 40adba0..c80d679 100644
--- a/pre_commit/languages/pygrep.py
+++ b/pre_commit/languages/pygrep.py
@@ -1,6 +1,7 @@
 import argparse
 import re
 import sys
+from typing import NamedTuple
 from typing import Optional
 from typing import Pattern
 from typing import Sequence
@@ -45,6 +46,46 @@ def _process_filename_at_once(pattern: Pattern[bytes], filename: str) -> int:
     return retv
 
 
+def _process_filename_by_line_negated(
+        pattern: Pattern[bytes],
+        filename: str,
+) -> int:
+    with open(filename, 'rb') as f:
+        for line in f:
+            if pattern.search(line):
+                return 0
+        else:
+            output.write_line(filename)
+            return 1
+
+
+def _process_filename_at_once_negated(
+        pattern: Pattern[bytes],
+        filename: str,
+) -> int:
+    with open(filename, 'rb') as f:
+        contents = f.read()
+    match = pattern.search(contents)
+    if match:
+        return 0
+    else:
+        output.write_line(filename)
+        return 1
+
+
+class Choice(NamedTuple):
+    multiline: bool
+    negate: bool
+
+
+FNS = {
+    Choice(multiline=True, negate=True): _process_filename_at_once_negated,
+    Choice(multiline=True, negate=False): _process_filename_at_once,
+    Choice(multiline=False, negate=True): _process_filename_by_line_negated,
+    Choice(multiline=False, negate=False): _process_filename_by_line,
+}
+
+
 def run_hook(
         hook: Hook,
         file_args: Sequence[str],
@@ -64,6 +105,7 @@ def main(argv: Optional[Sequence[str]] = None) -> int:
     )
     parser.add_argument('-i', '--ignore-case', action='store_true')
     parser.add_argument('--multiline', action='store_true')
+    parser.add_argument('--negate', action='store_true')
     parser.add_argument('pattern', help='python regex pattern.')
     parser.add_argument('filenames', nargs='*')
     args = parser.parse_args(argv)
@@ -75,11 +117,9 @@ def main(argv: Optional[Sequence[str]] = None) -> int:
     pattern = re.compile(args.pattern.encode(), flags)
 
     retv = 0
+    process_fn = FNS[Choice(multiline=args.multiline, negate=args.negate)]
     for filename in args.filenames:
-        if args.multiline:
-            retv |= _process_filename_at_once(pattern, filename)
-        else:
-            retv |= _process_filename_by_line(pattern, filename)
+        retv |= process_fn(pattern, filename)
     return retv
 
 
diff --git a/pre_commit/languages/python.py b/pre_commit/languages/python.py
index 7a68580..65f521c 100644
--- a/pre_commit/languages/python.py
+++ b/pre_commit/languages/python.py
@@ -114,11 +114,6 @@ def get_default_version() -> str:  # pragma: no cover (platform dependent)
     if _find_by_py_launcher(exe):
         return exe
 
-    # Give a best-effort try for windows
-    default_folder_name = exe.replace('.', '')
-    if os.path.exists(fr'C:\{default_folder_name}\python.exe'):
-        return exe
-
     # We tried!
     return C.DEFAULT
 
@@ -137,13 +132,11 @@ def _sys_executable_matches(version: str) -> bool:
     return sys.version_info[:len(info)] == info
 
 
-def norm_version(version: str) -> str:
-    if version == C.DEFAULT:
-        return os.path.realpath(sys.executable)
-
-    # first see if our current executable is appropriate
-    if _sys_executable_matches(version):
-        return sys.executable
+def norm_version(version: str) -> Optional[str]:
+    if version == C.DEFAULT:  # use virtualenv's default
+        return None
+    elif _sys_executable_matches(version):  # virtualenv defaults to our exe
+        return None
 
     if os.name == 'nt':  # pragma: no cover (windows)
         version_exec = _find_by_py_launcher(version)
@@ -155,12 +148,6 @@ def norm_version(version: str) -> str:
         if version_exec and version_exec != version:
             return version_exec
 
-        # If it is in the form pythonx.x search in the default
-        # place on windows
-        if version.startswith('python'):
-            default_folder_name = version.replace('.', '')
-            return fr'C:\{default_folder_name}\python.exe'
-
     # Otherwise assume it is a path
     return os.path.expanduser(version)
 
@@ -205,8 +192,10 @@ def install_environment(
         additional_dependencies: Sequence[str],
 ) -> None:
     envdir = prefix.path(helpers.environment_dir(ENVIRONMENT_DIR, version))
+    venv_cmd = [sys.executable, '-mvirtualenv', envdir]
     python = norm_version(version)
-    venv_cmd = (sys.executable, '-mvirtualenv', envdir, '-p', python)
+    if python is not None:
+        venv_cmd.extend(('-p', python))
     install_cmd = ('python', '-mpip', 'install', '.', *additional_dependencies)
 
     with clean_path_on_failure(envdir):
diff --git a/pre_commit/languages/ruby.py b/pre_commit/languages/ruby.py
index 73b23cc..1a0f0c7 100644
--- a/pre_commit/languages/ruby.py
+++ b/pre_commit/languages/ruby.py
@@ -8,7 +8,6 @@ from typing import Sequence
 from typing import Tuple
 
 import pre_commit.constants as C
-from pre_commit import parse_shebang
 from pre_commit.envcontext import envcontext
 from pre_commit.envcontext import PatchesT
 from pre_commit.envcontext import UNSET
@@ -26,7 +25,7 @@ healthy = helpers.basic_healthy
 
 @functools.lru_cache(maxsize=1)
 def get_default_version() -> str:
-    if all(parse_shebang.find_executable(exe) for exe in ('ruby', 'gem')):
+    if all(helpers.exe_exists(exe) for exe in ('ruby', 'gem')):
         return 'system'
     else:
         return C.DEFAULT
@@ -122,8 +121,8 @@ def install_environment(
                 # Need to call this before installing so rbenv's directories
                 # are set up
                 helpers.run_setup_cmd(prefix, ('rbenv', 'init', '-'))
-                # XXX: this will *always* fail if `version == C.DEFAULT`
-                _install_ruby(prefix, version)
+                if version != C.DEFAULT:
+                    _install_ruby(prefix, version)
                 # Need to call this after installing to set up the shims
                 helpers.run_setup_cmd(prefix, ('rbenv', 'rehash'))
 
@@ -134,7 +133,8 @@ def install_environment(
             helpers.run_setup_cmd(
                 prefix,
                 (
-                    'gem', 'install', '--no-document',
+                    'gem', 'install',
+                    '--no-document', '--no-format-executable',
                     *prefix.star('.gem'), *additional_dependencies,
                 ),
             )
diff --git a/pre_commit/main.py b/pre_commit/main.py
index 8647960..c1eb104 100644
--- a/pre_commit/main.py
+++ b/pre_commit/main.py
@@ -23,10 +23,8 @@ from pre_commit.commands.run import run
 from pre_commit.commands.sample_config import sample_config
 from pre_commit.commands.try_repo import try_repo
 from pre_commit.error_handler import error_handler
-from pre_commit.error_handler import FatalError
 from pre_commit.logging_handler import logging_handler
 from pre_commit.store import Store
-from pre_commit.util import CalledProcessError
 
 
 logger = logging.getLogger('pre_commit')
@@ -146,21 +144,8 @@ def _adjust_args_and_chdir(args: argparse.Namespace) -> None:
     if args.command == 'try-repo' and os.path.exists(args.repo):
         args.repo = os.path.abspath(args.repo)
 
-    try:
-        toplevel = git.get_root()
-    except CalledProcessError:
-        raise FatalError(
-            'git failed. Is it installed, and are you in a Git repository '
-            'directory?',
-        )
-    else:
-        if toplevel == '':  # pragma: no cover (old git)
-            raise FatalError(
-                'git toplevel unexpectedly empty! make sure you are not '
-                'inside the `.git` directory of your repository.',
-            )
-        else:
-            os.chdir(toplevel)
+    toplevel = git.get_root()
+    os.chdir(toplevel)
 
     args.config = os.path.relpath(args.config)
     if args.command in {'run', 'try-repo'}:
@@ -339,11 +324,11 @@ def main(argv: Optional[Sequence[str]] = None) -> int:
         parser.parse_args(['--help'])
 
     with error_handler(), logging_handler(args.color):
+        git.check_for_cygwin_mismatch()
+
         if args.command not in COMMANDS_NO_GIT:
             _adjust_args_and_chdir(args)
 
-        git.check_for_cygwin_mismatch()
-
         store = Store()
         store.mark_config_used(args.config)
 
diff --git a/pre_commit/make_archives.py b/pre_commit/make_archives.py
index c31bcd7..d320b83 100644
--- a/pre_commit/make_archives.py
+++ b/pre_commit/make_archives.py
@@ -15,8 +15,8 @@ from pre_commit.util import tmpdir
 
 
 REPOS = (
-    ('rbenv', 'git://github.com/rbenv/rbenv', 'a3fa9b7'),
-    ('ruby-build', 'git://github.com/rbenv/ruby-build', '1a902f3'),
+    ('rbenv', 'git://github.com/rbenv/rbenv', '0843745'),
+    ('ruby-build', 'git://github.com/rbenv/ruby-build', '258455e'),
     (
         'ruby-download',
         'git://github.com/garnieretienne/rvm-download',
diff --git a/pre_commit/resources/rbenv.tar.gz b/pre_commit/resources/rbenv.tar.gz
index 5307b19..97ac469 100644
--- a/pre_commit/resources/rbenv.tar.gz
+++ b/pre_commit/resources/rbenv.tar.gz
diff --git a/pre_commit/resources/ruby-build.tar.gz b/pre_commit/resources/ruby-build.tar.gz
index 4a69a09..4412ed4 100644
--- a/pre_commit/resources/ruby-build.tar.gz
+++ b/pre_commit/resources/ruby-build.tar.gz
diff --git a/pre_commit/util.py b/pre_commit/util.py
index 0338b37..f4cf704 100644
--- a/pre_commit/util.py
+++ b/pre_commit/util.py
@@ -16,7 +16,6 @@ from typing import IO
 from typing import Optional
 from typing import Tuple
 from typing import Type
-from typing import Union
 
 import yaml
 
@@ -29,8 +28,6 @@ else:  # pragma: no cover (<PY37)
     from importlib_resources import open_binary
     from importlib_resources import read_text
 
-EnvironT = Union[Dict[str, str], 'os._Environ']
-
 Loader = getattr(yaml, 'CSafeLoader', yaml.SafeLoader)
 yaml_load = functools.partial(yaml.load, Loader=Loader)
 Dumper = getattr(yaml, 'CSafeDumper', yaml.SafeDumper)
diff --git a/pre_commit/xargs.py b/pre_commit/xargs.py
index 5235dc6..7538b54 100644
--- a/pre_commit/xargs.py
+++ b/pre_commit/xargs.py
@@ -9,6 +9,7 @@ from typing import Callable
 from typing import Generator
 from typing import Iterable
 from typing import List
+from typing import MutableMapping
 from typing import Optional
 from typing import Sequence
 from typing import Tuple
@@ -17,13 +18,12 @@ from typing import TypeVar
 from pre_commit import parse_shebang
 from pre_commit.util import cmd_output_b
 from pre_commit.util import cmd_output_p
-from pre_commit.util import EnvironT
 
 TArg = TypeVar('TArg')
 TRet = TypeVar('TRet')
 
 
-def _environ_size(_env: Optional[EnvironT] = None) -> int:
+def _environ_size(_env: Optional[MutableMapping[str, str]] = None) -> int:
     environ = _env if _env is not None else getattr(os, 'environb', os.environ)
     size = 8 * len(environ)  # number of pointers in `envp`
     for k, v in environ.items():