Merging upstream version 2.5.1.

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

37 files changed, 456 insertions, 212 deletions

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index b51417d..36d73c7 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -12,25 +12,25 @@ repos:
     -   id: requirements-txt-fixer
     -   id: double-quote-string-fixer
 -   repo: https://gitlab.com/pycqa/flake8
-    rev: 3.7.9
+    rev: 3.8.0
     hooks:
     -   id: flake8
         additional_dependencies: [flake8-typing-imports==1.6.0]
 -   repo: https://github.com/pre-commit/mirrors-autopep8
-    rev: v1.5.1
+    rev: v1.5.2
     hooks:
     -   id: autopep8
 -   repo: https://github.com/pre-commit/pre-commit
-    rev: v2.2.0
+    rev: v2.4.0
     hooks:
     -   id: validate_manifest
 -   repo: https://github.com/asottile/pyupgrade
-    rev: v2.1.0
+    rev: v2.4.1
     hooks:
     -   id: pyupgrade
         args: [--py36-plus]
 -   repo: https://github.com/asottile/reorder_python_imports
-    rev: v2.1.0
+    rev: v2.3.0
     hooks:
     -   id: reorder-python-imports
         args: [--py3-plus]
@@ -40,7 +40,7 @@ repos:
     -   id: add-trailing-comma
         args: [--py36-plus]
 -   repo: https://github.com/asottile/setup-cfg-fmt
-    rev: v1.8.2
+    rev: v1.9.0
     hooks:
     -   id: setup-cfg-fmt
 -   repo: https://github.com/pre-commit/mirrors-mypy
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5b83319..375a9f3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,70 @@
+2.5.1 - 2020-06-09
+==================
+
+### Fixes
+- Prevent infinite recursion of post-checkout on clone
+    - #1497 PR by @asottile.
+    - #1496 issue by @admorgan.
+
+2.5.0 - 2020-06-08
+==================
+
+### Features
+- Expose a `PRE_COMMIT=1` environment variable when running hooks
+    - #1467 PR by @tech-chad.
+    - #1426 issue by @lorenzwalthert.
+
+### Fixes
+- Fix `UnicodeDecodeError` on windows when using the `py` launcher to detect
+  executables with non-ascii characters in the path
+    - #1474 PR by @asottile.
+    - #1472 issue by DrFobos.
+- Fix `DeprecationWarning` on python3.9 for `random.shuffle` method
+    - #1480 PR by @asottile.
+    - #1479 issue by @isidentical.
+- Normalize slashes earlier such that global `files` / `exclude` use forward
+  slashes on windows as well.
+    - #1494 PR by @asottile.
+    - #1476 issue by @harrybiddle.
+
+2.4.0 - 2020-05-11
+==================
+
+### Features
+- Add support for `post-commit` hooks
+    - #1415 PR by @ModischFabrications.
+    - #1411 issue by @ModischFabrications.
+- Silence pip version warning in python installation error
+    - #1412 PR by @asottile.
+- Improve python `healthy()` when upgrading operating systems.
+    - #1431 PR by @asottile.
+    - #1427 issue by @ahonnecke.
+- `language: python_venv` is now an alias to `language: python` (and will be
+  removed in a future version).
+    - #1431 PR by @asottile.
+- Speed up python `healthy()` check.
+    - #1431 PR by @asottile.
+- `pre-commit autoupdate` now tries to maintain quoting style of `rev`.
+    - #1435 PR by @marcjay.
+    - #1434 issue by @marcjay.
+
+### Fixes
+- Fix installation of go modules in `repo: local`.
+    - #1428 PR by @scop.
+- Fix committing with unstaged files and a failing `post-checkout` hook.
+    - #1422 PR by @domodwyer.
+    - #1418 issue by @domodwyer.
+- Fix installation of node hooks with system node installed on freebsd.
+    - #1443 PR by @asottile.
+    - #1440 issue by @jockej.
+- Fix ruby hooks when `GEM_PATH` is set globally.
+    - #1442 PR by @tdeo.
+- Improve error message when `pre-commit autoupdate` /
+  `pre-commit migrate-config` are run but the pre-commit configuration is not
+  valid yaml.
+    - #1448 PR by @asottile.
+    - #1447 issue by @rpdelaney.
+
 2.3.0 - 2020-04-22
 ==================
 
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 2b83c82..d70a89d 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -17,7 +17,8 @@ This is useful for running specific tests.  The easiest way to set this up
 is to run:
 
 1. `tox --devenv venv`  (note: requires tox>=3.13)
-2. `. venv/bin/activate`
+2. `. venv/bin/activate` (or follow the [activation instructions] for your
+   platform)
 
 This will create and put you into a virtualenv which has an editable
 installation of pre-commit.  Hack away!  Running `pre-commit` will reflect
@@ -144,3 +145,5 @@ This is usually the easiest to implement, most of them look the same as the
 `node` hook implementation:
 
 https://github.com/pre-commit/pre-commit/blob/160238220f022035c8ef869c9a8642f622c02118/pre_commit/languages/node.py#L72-L74
+
+[activation instructions]: https://virtualenv.pypa.io/en/latest/user_guide.html#activators
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 9b385b4..c21843e 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -10,7 +10,7 @@ resources:
       type: github
       endpoint: github
       name: asottile/azure-pipeline-templates
-      ref: refs/tags/v1.0.0
+      ref: refs/tags/v2.0.0
 
 jobs:
 - template: job--pre-commit.yml@asottile
@@ -40,7 +40,7 @@ jobs:
       displayName: install swift
 - template: job--python-tox.yml@asottile
   parameters:
-    toxenvs: [pypy3, py36, py37, py38]
+    toxenvs: [pypy3, py36, py37, py38, py39]
     os: linux
     pre_test:
     - task: UseRubyVersion@0
diff --git a/pre_commit/commands/autoupdate.py b/pre_commit/commands/autoupdate.py
index 8c9fdd7..87f6d53 100644
--- a/pre_commit/commands/autoupdate.py
+++ b/pre_commit/commands/autoupdate.py
@@ -84,7 +84,9 @@ def _check_hooks_still_exist_at_rev(
         )
 
 
-REV_LINE_RE = re.compile(r'^(\s+)rev:(\s*)([^\s#]+)(.*)(\r?\n)$', re.DOTALL)
+REV_LINE_RE = re.compile(
+    r'^(\s+)rev:(\s*)([\'"]?)([^\s#]+)(.*)(\r?\n)$', re.DOTALL,
+)
 
 
 def _original_lines(
@@ -116,15 +118,15 @@ def _write_new_config(path: str, rev_infos: List[Optional[RevInfo]]) -> None:
             continue
         match = REV_LINE_RE.match(lines[idx])
         assert match is not None
-        new_rev_s = yaml_dump({'rev': rev_info.rev})
+        new_rev_s = yaml_dump({'rev': rev_info.rev}, default_style=match[3])
         new_rev = new_rev_s.split(':', 1)[1].strip()
         if rev_info.frozen is not None:
             comment = f'  # frozen: {rev_info.frozen}'
-        elif match[4].strip().startswith('# frozen:'):
+        elif match[5].strip().startswith('# frozen:'):
             comment = ''
         else:
-            comment = match[4]
-        lines[idx] = f'{match[1]}rev:{match[2]}{new_rev}{comment}{match[5]}'
+            comment = match[5]
+        lines[idx] = f'{match[1]}rev:{match[2]}{new_rev}{comment}{match[6]}'
 
     with open(path, 'w', newline='') as f:
         f.write(''.join(lines))
diff --git a/pre_commit/commands/hook_impl.py b/pre_commit/commands/hook_impl.py
index 4843fc7..d0e226f 100644
--- a/pre_commit/commands/hook_impl.py
+++ b/pre_commit/commands/hook_impl.py
@@ -150,6 +150,7 @@ def _pre_push_ns(
 _EXPECTED_ARG_LENGTH_BY_HOOK = {
     'commit-msg': 1,
     'post-checkout': 3,
+    'post-commit': 0,
     'pre-commit': 0,
     'pre-merge-commit': 0,
     'pre-push': 2,
@@ -186,7 +187,7 @@ def _run_ns(
         return _pre_push_ns(color, args, stdin)
     elif hook_type in {'commit-msg', 'prepare-commit-msg'}:
         return _ns(hook_type, color, commit_msg_filename=args[0])
-    elif hook_type in {'pre-merge-commit', 'pre-commit'}:
+    elif hook_type in {'post-commit', 'pre-merge-commit', 'pre-commit'}:
         return _ns(hook_type, color)
     elif hook_type == 'post-checkout':
         return _ns(
diff --git a/pre_commit/commands/migrate_config.py b/pre_commit/commands/migrate_config.py
index d83b8e9..d580ff1 100644
--- a/pre_commit/commands/migrate_config.py
+++ b/pre_commit/commands/migrate_config.py
@@ -2,6 +2,7 @@ import re
 
 import yaml
 
+from pre_commit.clientlib import load_config
 from pre_commit.util import yaml_load
 
 
@@ -43,6 +44,9 @@ def _migrate_sha_to_rev(contents: str) -> str:
 
 
 def migrate_config(config_file: str, quiet: bool = False) -> int:
+    # ensure that the configuration is a valid pre-commit configuration
+    load_config(config_file)
+
     with open(config_file) as f:
         orig_contents = contents = f.read()
 
diff --git a/pre_commit/commands/run.py b/pre_commit/commands/run.py
index 8c8401c..567b7cd 100644
--- a/pre_commit/commands/run.py
+++ b/pre_commit/commands/run.py
@@ -72,13 +72,7 @@ def filter_by_include_exclude(
 
 
 class Classifier:
-    def __init__(self, filenames: Sequence[str]) -> None:
-        # on windows we normalize all filenames to use forward slashes
-        # this makes it easier to filter using the `files:` regex
-        # this also makes improperly quoted shell-based hooks work better
-        # see #1173
-        if os.altsep == '/' and os.sep == '\\':
-            filenames = [f.replace(os.sep, os.altsep) for f in filenames]
+    def __init__(self, filenames: Collection[str]) -> None:
         self.filenames = [f for f in filenames if os.path.lexists(f)]
 
     @functools.lru_cache(maxsize=None)
@@ -105,6 +99,22 @@ class Classifier:
         names = self.by_types(names, hook.types, hook.exclude_types)
         return tuple(names)
 
+    @classmethod
+    def from_config(
+            cls,
+            filenames: Collection[str],
+            include: str,
+            exclude: str,
+    ) -> 'Classifier':
+        # on windows we normalize all filenames to use forward slashes
+        # this makes it easier to filter using the `files:` regex
+        # this also makes improperly quoted shell-based hooks work better
+        # see #1173
+        if os.altsep == '/' and os.sep == '\\':
+            filenames = [f.replace(os.sep, os.altsep) for f in filenames]
+        filenames = filter_by_include_exclude(filenames, include, exclude)
+        return Classifier(filenames)
+
 
 def _get_skips(environ: EnvironT) -> Set[str]:
     skips = environ.get('SKIP', '')
@@ -221,7 +231,8 @@ def _compute_cols(hooks: Sequence[Hook]) -> int:
 
 
 def _all_filenames(args: argparse.Namespace) -> Collection[str]:
-    if args.hook_stage == 'post-checkout':  # no files for post-checkout
+    # these hooks do not operate on files
+    if args.hook_stage in {'post-checkout', 'post-commit'}:
         return ()
     elif args.hook_stage in {'prepare-commit-msg', 'commit-msg'}:
         return (args.commit_msg_filename,)
@@ -246,10 +257,9 @@ def _run_hooks(
     """Actually run the hooks."""
     skips = _get_skips(environ)
     cols = _compute_cols(hooks)
-    filenames = filter_by_include_exclude(
+    classifier = Classifier.from_config(
         _all_filenames(args), config['files'], config['exclude'],
     )
-    classifier = Classifier(filenames)
     retval = 0
     for hook in hooks:
         retval |= _run_single_hook(
@@ -323,6 +333,12 @@ def run(
             f'`--hook-stage {args.hook_stage}`',
         )
         return 1
+    # prevent recursive post-checkout hooks (#1418)
+    if (
+            args.hook_stage == 'post-checkout' and
+            environ.get('_PRE_COMMIT_SKIP_POST_CHECKOUT')
+    ):
+        return 0
 
     # Expose from-ref / to-ref as environment variables for hooks to consume
     if args.from_ref and args.to_ref:
@@ -340,6 +356,9 @@ def run(
     if args.checkout_type:
         environ['PRE_COMMIT_CHECKOUT_TYPE'] = args.checkout_type
 
+    # Set pre_commit flag
+    environ['PRE_COMMIT'] = '1'
+
     with contextlib.ExitStack() as exit_stack:
         if stash:
             exit_stack.enter_context(staged_files_only(store.directory))
diff --git a/pre_commit/constants.py b/pre_commit/constants.py
index e2b8e3a..5150fdc 100644
--- a/pre_commit/constants.py
+++ b/pre_commit/constants.py
@@ -17,8 +17,8 @@ VERSION = importlib_metadata.version('pre_commit')
 
 # `manual` is not invoked by any installed git hook.  See #719
 STAGES = (
-    'commit', 'merge-commit', 'prepare-commit-msg', 'commit-msg', 'manual',
-    'post-checkout', 'push',
+    'commit', 'merge-commit', 'prepare-commit-msg', 'commit-msg',
+    'post-commit', 'manual', 'post-checkout', 'push',
 )
 
 DEFAULT = 'default'
diff --git a/pre_commit/git.py b/pre_commit/git.py
index 7e757f2..576bef8 100644
--- a/pre_commit/git.py
+++ b/pre_commit/git.py
@@ -158,7 +158,8 @@ def init_repo(path: str, remote: str) -> None:
         remote = os.path.abspath(remote)
 
     env = no_git_env()
-    cmd_output_b('git', 'init', path, env=env)
+    # avoid the user's template so that hooks do not recurse
+    cmd_output_b('git', 'init', '--template=', path, env=env)
     cmd_output_b('git', 'remote', 'add', 'origin', remote, cwd=path, env=env)
 
 
diff --git a/pre_commit/languages/all.py b/pre_commit/languages/all.py
index 8f4ffa8..5609631 100644
--- a/pre_commit/languages/all.py
+++ b/pre_commit/languages/all.py
@@ -14,7 +14,6 @@ from pre_commit.languages import node
 from pre_commit.languages import perl
 from pre_commit.languages import pygrep
 from pre_commit.languages import python
-from pre_commit.languages import python_venv
 from pre_commit.languages import ruby
 from pre_commit.languages import rust
 from pre_commit.languages import script
@@ -49,7 +48,6 @@ languages = {
     'perl': Language(name='perl', ENVIRONMENT_DIR=perl.ENVIRONMENT_DIR, get_default_version=perl.get_default_version, healthy=perl.healthy, install_environment=perl.install_environment, run_hook=perl.run_hook),  # noqa: E501
     'pygrep': Language(name='pygrep', ENVIRONMENT_DIR=pygrep.ENVIRONMENT_DIR, get_default_version=pygrep.get_default_version, healthy=pygrep.healthy, install_environment=pygrep.install_environment, run_hook=pygrep.run_hook),  # noqa: E501
     'python': Language(name='python', ENVIRONMENT_DIR=python.ENVIRONMENT_DIR, get_default_version=python.get_default_version, healthy=python.healthy, install_environment=python.install_environment, run_hook=python.run_hook),  # noqa: E501
-    'python_venv': Language(name='python_venv', ENVIRONMENT_DIR=python_venv.ENVIRONMENT_DIR, get_default_version=python_venv.get_default_version, healthy=python_venv.healthy, install_environment=python_venv.install_environment, run_hook=python_venv.run_hook),  # noqa: E501
     'ruby': Language(name='ruby', ENVIRONMENT_DIR=ruby.ENVIRONMENT_DIR, get_default_version=ruby.get_default_version, healthy=ruby.healthy, install_environment=ruby.install_environment, run_hook=ruby.run_hook),  # noqa: E501
     'rust': Language(name='rust', ENVIRONMENT_DIR=rust.ENVIRONMENT_DIR, get_default_version=rust.get_default_version, healthy=rust.healthy, install_environment=rust.install_environment, run_hook=rust.run_hook),  # noqa: E501
     'script': Language(name='script', ENVIRONMENT_DIR=script.ENVIRONMENT_DIR, get_default_version=script.get_default_version, healthy=script.healthy, install_environment=script.install_environment, run_hook=script.run_hook),  # noqa: E501
@@ -57,4 +55,6 @@ languages = {
     'system': Language(name='system', ENVIRONMENT_DIR=system.ENVIRONMENT_DIR, get_default_version=system.get_default_version, healthy=system.healthy, install_environment=system.install_environment, run_hook=system.run_hook),  # noqa: E501
     # END GENERATED
 }
+# TODO: fully deprecate `python_venv`
+languages['python_venv'] = languages['python']
 all_languages = sorted(languages)
diff --git a/pre_commit/languages/helpers.py b/pre_commit/languages/helpers.py
index b5c95e5..01c65ab 100644
--- a/pre_commit/languages/helpers.py
+++ b/pre_commit/languages/helpers.py
@@ -18,7 +18,7 @@ from pre_commit.xargs import xargs
 if TYPE_CHECKING:
     from typing import NoReturn
 
-FIXED_RANDOM_SEED = 1542676186
+FIXED_RANDOM_SEED = 1542676187
 
 
 def run_setup_cmd(prefix: Prefix, cmd: Tuple[str, ...]) -> None:
@@ -92,7 +92,7 @@ def _shuffled(seq: Sequence[str]) -> List[str]:
     fixed_random.seed(FIXED_RANDOM_SEED, version=1)
 
     seq = list(seq)
-    random.shuffle(seq, random=fixed_random.random)
+    fixed_random.shuffle(seq)
     return seq
 
 
diff --git a/pre_commit/languages/node.py b/pre_commit/languages/node.py
index 9b636d3..26f4919 100644
--- a/pre_commit/languages/node.py
+++ b/pre_commit/languages/node.py
@@ -79,7 +79,7 @@ def install_environment(
 
     # https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx?f=255&MSPPError=-2147217396#maxpath
     if sys.platform == 'win32':  # pragma: no cover
-        envdir = f'\\\\?\\{os.path.normpath(envdir)}'
+        envdir = fr'\\?\{os.path.normpath(envdir)}'
     with clean_path_on_failure(envdir):
         cmd = [
             sys.executable, '-mnodeenv', '--prebuilt', '--clean-src', envdir,
diff --git a/pre_commit/languages/python.py b/pre_commit/languages/python.py
index 85d8281..6f7c900 100644
--- a/pre_commit/languages/python.py
+++ b/pre_commit/languages/python.py
@@ -2,8 +2,7 @@ import contextlib
 import functools
 import os
 import sys
-from typing import Callable
-from typing import ContextManager
+from typing import Dict
 from typing import Generator
 from typing import Optional
 from typing import Sequence
@@ -26,6 +25,28 @@ from pre_commit.util import cmd_output_b
 ENVIRONMENT_DIR = 'py_env'
 
 
+@functools.lru_cache(maxsize=None)
+def _version_info(exe: str) -> str:
+    prog = 'import sys;print(".".join(str(p) for p in sys.version_info))'
+    try:
+        return cmd_output(exe, '-S', '-c', prog)[1].strip()
+    except CalledProcessError:
+        return f'<<error retrieving version from {exe}>>'
+
+
+def _read_pyvenv_cfg(filename: str) -> Dict[str, str]:
+    ret = {}
+    with open(filename) as f:
+        for line in f:
+            try:
+                k, v = line.split('=')
+            except ValueError:  # blank line / comment / etc.
+                continue
+            else:
+                ret[k.strip()] = v.strip()
+    return ret
+
+
 def bin_dir(venv: str) -> str:
     """On windows there's a different directory for the virtualenv"""
     bin_part = 'Scripts' if os.name == 'nt' else 'bin'
@@ -34,6 +55,7 @@ def bin_dir(venv: str) -> str:
 
 def get_env_patch(venv: str) -> PatchesT:
     return (
+        ('PIP_DISABLE_PIP_VERSION_CHECK', '1'),
         ('PYTHONHOME', UNSET),
         ('VIRTUAL_ENV', venv),
         ('PATH', (bin_dir(venv), os.pathsep, Var('PATH'))),
@@ -45,9 +67,10 @@ def _find_by_py_launcher(
 ) -> Optional[str]:  # pragma: no cover (windows only)
     if version.startswith('python'):
         num = version[len('python'):]
+        cmd = ('py', f'-{num}', '-c', 'import sys; print(sys.executable)')
+        env = dict(os.environ, PYTHONIOENCODING='UTF-8')
         try:
-            cmd = ('py', f'-{num}', '-c', 'import sys; print(sys.executable)')
-            return cmd_output(*cmd)[1].strip()
+            return cmd_output(*cmd, env=env)[1].strip()
         except CalledProcessError:
             pass
     return None
@@ -115,6 +138,9 @@ def _sys_executable_matches(version: str) -> bool:
 
 
 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
@@ -139,70 +165,59 @@ def norm_version(version: str) -> str:
     return os.path.expanduser(version)
 
 
-def py_interface(
-        _dir: str,
-        _make_venv: Callable[[str, str], None],
-) -> Tuple[
-    Callable[[Prefix, str], ContextManager[None]],
-    Callable[[Prefix, str], bool],
-    Callable[[Hook, Sequence[str], bool], Tuple[int, bytes]],
-    Callable[[Prefix, str, Sequence[str]], None],
-]:
-    @contextlib.contextmanager
-    def in_env(
-            prefix: Prefix,
-            language_version: str,
-    ) -> Generator[None, None, None]:
-        envdir = prefix.path(helpers.environment_dir(_dir, language_version))
-        with envcontext(get_env_patch(envdir)):
-            yield
-
-    def healthy(prefix: Prefix, language_version: str) -> bool:
-        envdir = helpers.environment_dir(_dir, language_version)
-        exe_name = 'python.exe' if sys.platform == 'win32' else 'python'
-        py_exe = prefix.path(bin_dir(envdir), exe_name)
-        with in_env(prefix, language_version):
-            retcode, _, _ = cmd_output_b(
-                py_exe, '-c', 'import ctypes, datetime, io, os, ssl, weakref',
-                cwd='/',
-                retcode=None,
-            )
-        return retcode == 0
-
-    def run_hook(
-            hook: Hook,
-            file_args: Sequence[str],
-            color: bool,
-    ) -> Tuple[int, bytes]:
-        with in_env(hook.prefix, hook.language_version):
-            return helpers.run_xargs(hook, hook.cmd, file_args, color=color)
-
-    def install_environment(
-            prefix: Prefix,
-            version: str,
-            additional_dependencies: Sequence[str],
-    ) -> None:
-        directory = helpers.environment_dir(_dir, version)
-        install = ('python', '-mpip', 'install', '.', *additional_dependencies)
-
-        env_dir = prefix.path(directory)
-        with clean_path_on_failure(env_dir):
-            if version != C.DEFAULT:
-                python = norm_version(version)
-            else:
-                python = os.path.realpath(sys.executable)
-            _make_venv(env_dir, python)
-            with in_env(prefix, version):
-                helpers.run_setup_cmd(prefix, install)
+@contextlib.contextmanager
+def in_env(
+        prefix: Prefix,
+        language_version: str,
+) -> Generator[None, None, None]:
+    directory = helpers.environment_dir(ENVIRONMENT_DIR, language_version)
+    envdir = prefix.path(directory)
+    with envcontext(get_env_patch(envdir)):
+        yield
 
-    return in_env, healthy, run_hook, install_environment
 
+def healthy(prefix: Prefix, language_version: str) -> bool:
+    directory = helpers.environment_dir(ENVIRONMENT_DIR, language_version)
+    envdir = prefix.path(directory)
+    pyvenv_cfg = os.path.join(envdir, 'pyvenv.cfg')
 
-def make_venv(envdir: str, python: str) -> None:
-    env = dict(os.environ, VIRTUALENV_NO_DOWNLOAD='1')
-    cmd = (sys.executable, '-mvirtualenv', envdir, '-p', python)
-    cmd_output_b(*cmd, env=env, cwd='/')
+    # created with "old" virtualenv
+    if not os.path.exists(pyvenv_cfg):
+        return False
+
+    exe_name = 'python.exe' if sys.platform == 'win32' else 'python'
+    py_exe = prefix.path(bin_dir(envdir), exe_name)
+    cfg = _read_pyvenv_cfg(pyvenv_cfg)
+
+    return (
+        'version_info' in cfg and
+        _version_info(py_exe) == cfg['version_info'] and (
+            'base-executable' not in cfg or
+            _version_info(cfg['base-executable']) == cfg['version_info']
+        )
+    )
 
 
-_interface = py_interface(ENVIRONMENT_DIR, make_venv)
-in_env, healthy, run_hook, install_environment = _interface
+def install_environment(
+        prefix: Prefix,
+        version: str,
+        additional_dependencies: Sequence[str],
+) -> None:
+    envdir = prefix.path(helpers.environment_dir(ENVIRONMENT_DIR, version))
+    python = norm_version(version)
+    venv_cmd = (sys.executable, '-mvirtualenv', envdir, '-p', python)
+    install_cmd = ('python', '-mpip', 'install', '.', *additional_dependencies)
+
+    with clean_path_on_failure(envdir):
+        cmd_output_b(*venv_cmd, cwd='/')
+        with in_env(prefix, version):
+            helpers.run_setup_cmd(prefix, install_cmd)
+
+
+def run_hook(
+        hook: Hook,
+        file_args: Sequence[str],
+        color: bool,
+) -> Tuple[int, bytes]:
+    with in_env(hook.prefix, hook.language_version):
+        return helpers.run_xargs(hook, hook.cmd, file_args, color=color)
diff --git a/pre_commit/languages/python_venv.py b/pre_commit/languages/python_venv.py
deleted file mode 100644
index 5404c8b..0000000
--- a/pre_commit/languages/python_venv.py
+++ /dev/null
@@ -1,46 +0,0 @@
-import os.path
-
-from pre_commit.languages import python
-from pre_commit.util import CalledProcessError
-from pre_commit.util import cmd_output
-from pre_commit.util import cmd_output_b
-
-ENVIRONMENT_DIR = 'py_venv'
-get_default_version = python.get_default_version
-
-
-def orig_py_exe(exe: str) -> str:  # pragma: no cover (platform specific)
-    """A -mvenv virtualenv made from a -mvirtualenv virtualenv installs
-    packages to the incorrect location.  Attempt to find the _original_ exe
-    and invoke `-mvenv` from there.
-
-    See:
-    - https://github.com/pre-commit/pre-commit/issues/755
-    - https://github.com/pypa/virtualenv/issues/1095
-    - https://bugs.python.org/issue30811
-    """
-    try:
-        prefix_script = 'import sys; print(sys.real_prefix)'
-        _, prefix, _ = cmd_output(exe, '-c', prefix_script)
-        prefix = prefix.strip()
-    except CalledProcessError:
-        # not created from -mvirtualenv
-        return exe
-
-    if os.name == 'nt':
-        expected = os.path.join(prefix, 'python.exe')
-    else:
-        expected = os.path.join(prefix, 'bin', os.path.basename(exe))
-
-    if os.path.exists(expected):
-        return expected
-    else:
-        return exe
-
-
-def make_venv(envdir: str, python: str) -> None:
-    cmd_output_b(orig_py_exe(python), '-mvenv', envdir, cwd='/')
-
-
-_interface = python.py_interface(ENVIRONMENT_DIR, make_venv)
-in_env, healthy, run_hook, install_environment = _interface
diff --git a/pre_commit/languages/ruby.py b/pre_commit/languages/ruby.py
index 61241f8..fe524ec 100644
--- a/pre_commit/languages/ruby.py
+++ b/pre_commit/languages/ruby.py
@@ -9,6 +9,7 @@ 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 UNSET
 from pre_commit.envcontext import Var
 from pre_commit.hook import Hook
 from pre_commit.languages import helpers
@@ -28,6 +29,7 @@ def get_env_patch(
 ) -> PatchesT:  # pragma: win32 no cover
     patches: PatchesT = (
         ('GEM_HOME', os.path.join(venv, 'gems')),
+        ('GEM_PATH', UNSET),
         ('RBENV_ROOT', venv),
         ('BUNDLE_IGNORE_CONFIG', '1'),
         (
diff --git a/pre_commit/main.py b/pre_commit/main.py
index 790b347..874eb53 100644
--- a/pre_commit/main.py
+++ b/pre_commit/main.py
@@ -79,7 +79,7 @@ def _add_hook_type_option(parser: argparse.ArgumentParser) -> None:
     parser.add_argument(
         '-t', '--hook-type', choices=(
             'pre-commit', 'pre-merge-commit', 'pre-push',
-            'prepare-commit-msg', 'commit-msg', 'post-checkout',
+            'prepare-commit-msg', 'commit-msg', 'post-commit', 'post-checkout',
         ),
         action=AppendReplaceDefault,
         default=['pre-commit'],
diff --git a/pre_commit/meta_hooks/check_hooks_apply.py b/pre_commit/meta_hooks/check_hooks_apply.py
index d0244a9..a1e9352 100644
--- a/pre_commit/meta_hooks/check_hooks_apply.py
+++ b/pre_commit/meta_hooks/check_hooks_apply.py
@@ -11,10 +11,13 @@ from pre_commit.store import Store
 
 
 def check_all_hooks_match_files(config_file: str) -> int:
-    classifier = Classifier(git.get_all_files())
+    config = load_config(config_file)
+    classifier = Classifier.from_config(
+        git.get_all_files(), config['files'], config['exclude'],
+    )
     retv = 0
 
-    for hook in all_hooks(load_config(config_file), Store()):
+    for hook in all_hooks(config, Store()):
         if hook.always_run or hook.language == 'fail':
             continue
         elif not classifier.filenames_for_hook(hook):
diff --git a/pre_commit/meta_hooks/check_useless_excludes.py b/pre_commit/meta_hooks/check_useless_excludes.py
index 30b8d81..db6865c 100644
--- a/pre_commit/meta_hooks/check_useless_excludes.py
+++ b/pre_commit/meta_hooks/check_useless_excludes.py
@@ -28,11 +28,14 @@ def exclude_matches_any(
 
 def check_useless_excludes(config_file: str) -> int:
     config = load_config(config_file)
-    classifier = Classifier(git.get_all_files())
+    filenames = git.get_all_files()
+    classifier = Classifier.from_config(
+        filenames, config['files'], config['exclude'],
+    )
     retv = 0
 
     exclude = config['exclude']
-    if not exclude_matches_any(classifier.filenames, '', exclude):
+    if not exclude_matches_any(filenames, '', exclude):
         print(
             f'The global exclude pattern {exclude!r} does not match any files',
         )
diff --git a/pre_commit/resources/empty_template_go.mod b/pre_commit/resources/empty_template_go.mod
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/pre_commit/resources/empty_template_go.mod
diff --git a/pre_commit/staged_files_only.py b/pre_commit/staged_files_only.py
index 09d323d..6179301 100644
--- a/pre_commit/staged_files_only.py
+++ b/pre_commit/staged_files_only.py
@@ -56,8 +56,10 @@ def _unstaged_changes_cleared(patch_dir: str) -> Generator[None, None, None]:
         with open(patch_filename, 'wb') as patch_file:
             patch_file.write(diff_stdout_binary)
 
-        # Clear the working directory of unstaged changes
-        cmd_output_b('git', 'checkout', '--', '.')
+        # prevent recursive post-checkout hooks (#1418)
+        no_checkout_env = dict(os.environ, _PRE_COMMIT_SKIP_POST_CHECKOUT='1')
+        cmd_output_b('git', 'checkout', '--', '.', env=no_checkout_env)
+
         try:
             yield
         finally:
@@ -72,8 +74,9 @@ def _unstaged_changes_cleared(patch_dir: str) -> Generator[None, None, None]:
                 # We failed to apply the patch, presumably due to fixes made
                 # by hooks.
                 # Roll back the changes made by hooks.
-                cmd_output_b('git', 'checkout', '--', '.')
+                cmd_output_b('git', 'checkout', '--', '.', env=no_checkout_env)
                 _git_apply(patch_filename)
+
             logger.info(f'Restored changes from {patch_filename}.')
     else:
         # There weren't any staged files so we don't need to do anything
diff --git a/pre_commit/store.py b/pre_commit/store.py
index 760b37a..6d8c40a 100644
--- a/pre_commit/store.py
+++ b/pre_commit/store.py
@@ -30,10 +30,11 @@ def _get_default_directory() -> str:
     `Store.get_default_directory` can be mocked in tests and
     `_get_default_directory` can be tested.
     """
-    return os.environ.get('PRE_COMMIT_HOME') or os.path.join(
+    ret = os.environ.get('PRE_COMMIT_HOME') or os.path.join(
         os.environ.get('XDG_CACHE_HOME') or os.path.expanduser('~/.cache'),
         'pre-commit',
     )
+    return os.path.realpath(ret)
 
 
 class Store:
@@ -182,9 +183,9 @@ class Store:
         return self._new_repo(repo, ref, deps, clone_strategy)
 
     LOCAL_RESOURCES = (
-        'Cargo.toml', 'main.go', 'main.rs', '.npmignore', 'package.json',
-        'pre_commit_dummy_package.gemspec', 'setup.py', 'environment.yml',
-        'Makefile.PL',
+        'Cargo.toml', 'main.go', 'go.mod', 'main.rs', '.npmignore',
+        'package.json', 'pre_commit_dummy_package.gemspec', 'setup.py',
+        'environment.yml', 'Makefile.PL',
     )
 
     def make_local(self, deps: Sequence[str]) -> str:
diff --git a/pre_commit/util.py b/pre_commit/util.py
index 2db579a..0338b37 100644
--- a/pre_commit/util.py
+++ b/pre_commit/util.py
@@ -36,10 +36,11 @@ yaml_load = functools.partial(yaml.load, Loader=Loader)
 Dumper = getattr(yaml, 'CSafeDumper', yaml.SafeDumper)
 
 
-def yaml_dump(o: Any) -> str:
+def yaml_dump(o: Any, **kwargs: Any) -> str:
     # when python/mypy#1484 is solved, this can be `functools.partial`
     return yaml.dump(
         o, Dumper=Dumper, default_flow_style=False, indent=4, sort_keys=False,
+        **kwargs,
     )
 
 
diff --git a/setup.cfg b/setup.cfg
index 2e69d50..f1ce18d 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,6 +1,6 @@
 [metadata]
 name = pre_commit
-version = 2.3.0
+version = 2.5.1
 description = A framework for managing and maintaining multi-language pre-commit hooks.
 long_description = file: README.md
 long_description_content_type = text/markdown
@@ -27,7 +27,7 @@ install_requires =
     nodeenv>=0.11.1
     pyyaml>=5.1
     toml
-    virtualenv>=15.2
+    virtualenv>=20.0.8
     importlib-metadata;python_version<"3.8"
     importlib-resources;python_version<"3.7"
 python_requires = >=3.6.1
diff --git a/testing/gen-languages-all b/testing/gen-languages-all
index 6d0b26f..2bff7be 100755
--- a/testing/gen-languages-all
+++ b/testing/gen-languages-all
@@ -3,8 +3,7 @@ import sys
 
 LANGUAGES = [
     'conda', 'docker', 'docker_image', 'fail', 'golang', 'node', 'perl',
-    'pygrep', 'python', 'python_venv', 'ruby', 'rust', 'script', 'swift',
-    'system',
+    'pygrep', 'python', 'ruby', 'rust', 'script', 'swift', 'system',
 ]
 FIELDS = [
     'ENVIRONMENT_DIR', 'get_default_version', 'healthy', 'install_environment',
diff --git a/testing/util.py b/testing/util.py
index 439bee7..bfe1421 100644
--- a/testing/util.py
+++ b/testing/util.py
@@ -45,20 +45,6 @@ xfailif_windows_no_ruby = pytest.mark.xfail(
 xfailif_windows = pytest.mark.xfail(os.name == 'nt', reason='windows')
 
 
-def supports_venv():  # pragma: no cover (platform specific)
-    try:
-        __import__('ensurepip')
-        __import__('venv')
-        return True
-    except ImportError:
-        return False
-
-
-xfailif_no_venv = pytest.mark.xfail(
-    not supports_venv(), reason='Does not support venv module',
-)
-
-
 def run_opts(
         all_files=False,
         files=(),
@@ -103,10 +89,12 @@ def cwd(path):
         os.chdir(original_cwd)
 
 
-def git_commit(*args, fn=cmd_output, msg='commit!', **kwargs):
+def git_commit(*args, fn=cmd_output, msg='commit!', all_files=True, **kwargs):
     kwargs.setdefault('stderr', subprocess.STDOUT)
 
-    cmd = ('git', 'commit', '--allow-empty', '--no-gpg-sign', '-a') + args
+    cmd = ('git', 'commit', '--allow-empty', '--no-gpg-sign', *args)
+    if all_files:  # allow skipping `-a` with `all_files=False`
+        cmd += ('-a',)
     if msg is not None:  # allow skipping `-m` with `msg=None`
         cmd += ('-m', msg)
     ret, out, _ = fn(*cmd, **kwargs)
diff --git a/tests/commands/autoupdate_test.py b/tests/commands/autoupdate_test.py
index 25161d1..bd89c1d 100644
--- a/tests/commands/autoupdate_test.py
+++ b/tests/commands/autoupdate_test.py
@@ -414,9 +414,9 @@ def test_autoupdate_local_hooks(in_git_dir, store):
     config = sample_local_config()
     add_config_to_repo('.', config)
     assert autoupdate(C.CONFIG_FILE, store, freeze=False, tags_only=False) == 0
-    new_config_writen = read_config('.')
-    assert len(new_config_writen['repos']) == 1
-    assert new_config_writen['repos'][0] == config
+    new_config_written = read_config('.')
+    assert len(new_config_written['repos']) == 1
+    assert new_config_written['repos'][0] == config
 
 
 def test_autoupdate_local_hooks_with_out_of_date_repo(
@@ -429,9 +429,9 @@ def test_autoupdate_local_hooks_with_out_of_date_repo(
     config = {'repos': [local_config, stale_config]}
     write_config('.', config)
     assert autoupdate(C.CONFIG_FILE, store, freeze=False, tags_only=False) == 0
-    new_config_writen = read_config('.')
-    assert len(new_config_writen['repos']) == 2
-    assert new_config_writen['repos'][0] == local_config
+    new_config_written = read_config('.')
+    assert len(new_config_written['repos']) == 2
+    assert new_config_written['repos'][0] == local_config
 
 
 def test_autoupdate_meta_hooks(tmpdir, store):
@@ -474,3 +474,23 @@ def test_updates_old_format_to_new_format(tmpdir, capsys, store):
     )
     out, _ = capsys.readouterr()
     assert out == 'Configuration has been migrated.\n'
+
+
+def test_maintains_rev_quoting_style(tmpdir, out_of_date, store):
+    fmt = (
+        'repos:\n'
+        '-   repo: {path}\n'
+        '    rev: "{rev}"\n'
+        '    hooks:\n'
+        '    -   id: foo\n'
+        '-   repo: {path}\n'
+        "    rev: '{rev}'\n"
+        '    hooks:\n'
+        '    -   id: foo\n'
+    )
+    cfg = tmpdir.join(C.CONFIG_FILE)
+    cfg.write(fmt.format(path=out_of_date.path, rev=out_of_date.original_rev))
+
+    assert autoupdate(str(cfg), store, freeze=False, tags_only=False) == 0
+    expected = fmt.format(path=out_of_date.path, rev=out_of_date.head_rev)
+    assert cfg.read() == expected
diff --git a/tests/commands/hook_impl_test.py b/tests/commands/hook_impl_test.py
index ddf65b7..2fc0146 100644
--- a/tests/commands/hook_impl_test.py
+++ b/tests/commands/hook_impl_test.py
@@ -96,6 +96,7 @@ def test_run_legacy_recursive(tmpdir):
         ('pre-merge-commit', []),
         ('pre-push', ['branch_name', 'remote_name']),
         ('commit-msg', ['.git/COMMIT_EDITMSG']),
+        ('post-commit', []),
         ('post-checkout', ['old_head', 'new_head', '1']),
         # multiple choices for commit-editmsg
         ('prepare-commit-msg', ['.git/COMMIT_EDITMSG']),
@@ -117,7 +118,7 @@ def test_check_args_length_error_too_many_plural():
     )
 
 
-def test_check_args_length_error_too_many_singluar():
+def test_check_args_length_error_too_many_singular():
     with pytest.raises(SystemExit) as excinfo:
         hook_impl._check_args_length('commit-msg', [])
     msg, = excinfo.value.args
@@ -149,6 +150,13 @@ def test_run_ns_commit_msg():
     assert ns.commit_msg_filename == '.git/COMMIT_MSG'
 
 
+def test_run_ns_post_commit():
+    ns = hook_impl._run_ns('post-commit', True, (), b'')
+    assert ns is not None
+    assert ns.hook_stage == 'post-commit'
+    assert ns.color is True
+
+
 def test_run_ns_post_checkout():
     ns = hook_impl._run_ns('post-checkout', True, ('a', 'b', 'c'), b'')
     assert ns is not None
diff --git a/tests/commands/install_uninstall_test.py b/tests/commands/install_uninstall_test.py
index 66b9190..5809a3f 100644
--- a/tests/commands/install_uninstall_test.py
+++ b/tests/commands/install_uninstall_test.py
@@ -726,6 +726,32 @@ def test_commit_msg_legacy(commit_msg_repo, tempdir_factory, store):
     assert second_line.startswith('Must have "Signed off by:"...')
 
 
+def test_post_commit_integration(tempdir_factory, store):
+    path = git_dir(tempdir_factory)
+    config = [
+        {
+            'repo': 'local',
+            'hooks': [{
+                'id': 'post-commit',
+                'name': 'Post commit',
+                'entry': 'touch post-commit.tmp',
+                'language': 'system',
+                'always_run': True,
+                'verbose': True,
+                'stages': ['post-commit'],
+            }],
+        },
+    ]
+    write_config(path, config)
+    with cwd(path):
+        _get_commit_output(tempdir_factory)
+        assert not os.path.exists('post-commit.tmp')
+
+        install(C.CONFIG_FILE, store, hook_types=['post-commit'])
+        _get_commit_output(tempdir_factory)
+        assert os.path.exists('post-commit.tmp')
+
+
 def test_post_checkout_integration(tempdir_factory, store):
     path = git_dir(tempdir_factory)
     config = [
@@ -763,6 +789,37 @@ def test_post_checkout_integration(tempdir_factory, store):
         assert 'some_file' not in stderr
 
 
+def test_skips_post_checkout_unstaged_changes(tempdir_factory, store):
+    path = git_dir(tempdir_factory)
+    config = {
+        'repo': 'local',
+        'hooks': [{
+            'id': 'fail',
+            'name': 'fail',
+            'entry': 'fail',
+            'language': 'fail',
+            'always_run': True,
+            'stages': ['post-checkout'],
+        }],
+    }
+    write_config(path, config)
+    with cwd(path):
+        cmd_output('git', 'add', '.')
+        _get_commit_output(tempdir_factory)
+
+        install(C.CONFIG_FILE, store, hook_types=['pre-commit'])
+        install(C.CONFIG_FILE, store, hook_types=['post-checkout'])
+
+        # make an unstaged change so staged_files_only fires
+        open('file', 'a').close()
+        cmd_output('git', 'add', 'file')
+        with open('file', 'w') as f:
+            f.write('unstaged changes')
+
+        retc, out = _get_commit_output(tempdir_factory, all_files=False)
+        assert retc == 0
+
+
 def test_prepare_commit_msg_integration_failing(
         failing_prepare_commit_msg_repo, tempdir_factory, store,
 ):
diff --git a/tests/commands/migrate_config_test.py b/tests/commands/migrate_config_test.py
index efc0d1c..6a049d5 100644
--- a/tests/commands/migrate_config_test.py
+++ b/tests/commands/migrate_config_test.py
@@ -1,6 +1,7 @@
 import pytest
 
 import pre_commit.constants as C
+from pre_commit.clientlib import InvalidConfigError
 from pre_commit.commands.migrate_config import _indent
 from pre_commit.commands.migrate_config import migrate_config
 
@@ -147,10 +148,10 @@ def test_migrate_config_sha_to_rev(tmpdir):
 
 
 @pytest.mark.parametrize('contents', ('', '\n'))
-def test_empty_configuration_file_user_error(tmpdir, contents):
+def test_migrate_config_invalid_configuration(tmpdir, contents):
     cfg = tmpdir.join(C.CONFIG_FILE)
     cfg.write(contents)
-    with tmpdir.as_cwd():
-        assert not migrate_config(C.CONFIG_FILE)
+    with tmpdir.as_cwd(), pytest.raises(InvalidConfigError):
+        migrate_config(C.CONFIG_FILE)
     # even though the config is invalid, this should be a noop
     assert cfg.read() == contents
diff --git a/tests/commands/run_test.py b/tests/commands/run_test.py
index c51bcff..2461ed5 100644
--- a/tests/commands/run_test.py
+++ b/tests/commands/run_test.py
@@ -939,7 +939,7 @@ def test_classifier_normalizes_filenames_on_windows_to_forward_slashes(tmpdir):
         tmpdir.join('a/b/c').ensure()
         with mock.patch.object(os, 'altsep', '/'):
             with mock.patch.object(os, 'sep', '\\'):
-                classifier = Classifier((r'a\b\c',))
+                classifier = Classifier.from_config((r'a\b\c',), '', '^$')
                 assert classifier.filenames == ['a/b/c']
 
 
@@ -947,7 +947,7 @@ def test_classifier_does_not_normalize_backslashes_non_windows(tmpdir):
     with mock.patch.object(os.path, 'lexists', return_value=True):
         with mock.patch.object(os, 'altsep', None):
             with mock.patch.object(os, 'sep', '/'):
-                classifier = Classifier((r'a/b\c',))
+                classifier = Classifier.from_config((r'a/b\c',), '', '^$')
                 assert classifier.filenames == [r'a/b\c']
 
 
@@ -1022,3 +1022,18 @@ def test_args_hook_only(cap_out, store, repo_with_passing_hook):
         run_opts(hook='do_not_commit'),
     )
     assert b'identity-copy' not in printed
+
+
+def test_skipped_without_any_setup_for_post_checkout(in_git_dir, store):
+    environ = {'_PRE_COMMIT_SKIP_POST_CHECKOUT': '1'}
+    opts = run_opts(hook_stage='post-checkout')
+    assert run(C.CONFIG_FILE, store, opts, environ=environ) == 0
+
+
+def test_pre_commit_env_variable_set(cap_out, store, repo_with_passing_hook):
+    args = run_opts()
+    environ: EnvironT = {}
+    ret, printed = _do_run(
+        cap_out, store, repo_with_passing_hook, args, environ,
+    )
+    assert environ['PRE_COMMIT'] == '1'
diff --git a/tests/git_test.py b/tests/git_test.py
index e73a6f2..fafd4a6 100644
--- a/tests/git_test.py
+++ b/tests/git_test.py
@@ -186,3 +186,8 @@ def test_no_git_env():
         'GIT_SSH': '/usr/bin/ssh',
         'GIT_SSH_COMMAND': 'ssh -o',
     }
+
+
+def test_init_repo_no_hooks(tmpdir):
+    git.init_repo(str(tmpdir), remote='dne')
+    assert not tmpdir.join('.git/hooks').exists()
diff --git a/tests/languages/helpers_test.py b/tests/languages/helpers_test.py
index c52e947..fa493cc 100644
--- a/tests/languages/helpers_test.py
+++ b/tests/languages/helpers_test.py
@@ -78,5 +78,5 @@ def test_target_concurrency_cpu_count_not_implemented():
 
 def test_shuffled_is_deterministic():
     seq = [str(i) for i in range(10)]
-    expected = ['3', '7', '8', '2', '4', '6', '5', '1', '0', '9']
+    expected = ['4', '0', '5', '1', '8', '6', '2', '3', '7', '9']
     assert helpers._shuffled(seq) == expected
diff --git a/tests/languages/python_test.py b/tests/languages/python_test.py
index 34c6c7f..c419ad6 100644
--- a/tests/languages/python_test.py
+++ b/tests/languages/python_test.py
@@ -5,10 +5,23 @@ from unittest import mock
 import pytest
 
 import pre_commit.constants as C
+from pre_commit.envcontext import envcontext
 from pre_commit.languages import python
 from pre_commit.prefix import Prefix
 
 
+def test_read_pyvenv_cfg(tmpdir):
+    pyvenv_cfg = tmpdir.join('pyvenv.cfg')
+    pyvenv_cfg.write(
+        '# I am a comment\n'
+        '\n'
+        'foo = bar\n'
+        'version-info=123\n',
+    )
+    expected = {'foo': 'bar', 'version-info': '123'}
+    assert python._read_pyvenv_cfg(pyvenv_cfg) == expected
+
+
 def test_norm_version_expanduser():
     home = os.path.expanduser('~')
     if os.name == 'nt':  # pragma: nt cover
@@ -21,6 +34,10 @@ def test_norm_version_expanduser():
     assert result == expected_path
 
 
+def test_norm_version_of_default_is_sys_executable():
+    assert python.norm_version('default') == os.path.realpath(sys.executable)
+
+
 @pytest.mark.parametrize('v', ('python3.6', 'python3', 'python'))
 def test_sys_executable_matches(v):
     with mock.patch.object(sys, 'version_info', (3, 6, 7)):
@@ -49,27 +66,78 @@ def test_find_by_sys_executable(exe, realpath, expected):
                 assert python._find_by_sys_executable() == expected
 
 
-def test_healthy_types_py_in_cwd(tmpdir):
+@pytest.fixture
+def python_dir(tmpdir):
     with tmpdir.as_cwd():
         prefix = tmpdir.join('prefix').ensure_dir()
         prefix.join('setup.py').write('import setuptools; setuptools.setup()')
         prefix = Prefix(str(prefix))
-        python.install_environment(prefix, C.DEFAULT, ())
+        yield prefix, tmpdir
 
-        # even if a `types.py` file exists, should still be healthy
-        tmpdir.join('types.py').ensure()
-        assert python.healthy(prefix, C.DEFAULT) is True
 
+def test_healthy_default_creator(python_dir):
+    prefix, tmpdir = python_dir
 
-def test_healthy_python_goes_missing(tmpdir):
-    with tmpdir.as_cwd():
-        prefix = tmpdir.join('prefix').ensure_dir()
-        prefix.join('setup.py').write('import setuptools; setuptools.setup()')
-        prefix = Prefix(str(prefix))
+    python.install_environment(prefix, C.DEFAULT, ())
+
+    # should be healthy right after creation
+    assert python.healthy(prefix, C.DEFAULT) is True
+
+    # even if a `types.py` file exists, should still be healthy
+    tmpdir.join('types.py').ensure()
+    assert python.healthy(prefix, C.DEFAULT) is True
+
+
+def test_healthy_venv_creator(python_dir):
+    # venv creator produces slightly different pyvenv.cfg
+    prefix, tmpdir = python_dir
+
+    with envcontext((('VIRTUALENV_CREATOR', 'venv'),)):
         python.install_environment(prefix, C.DEFAULT, ())
 
-        exe_name = 'python' if sys.platform != 'win32' else 'python.exe'
-        py_exe = prefix.path(python.bin_dir('py_env-default'), exe_name)
-        os.remove(py_exe)
+    assert python.healthy(prefix, C.DEFAULT) is True
+
+
+def test_unhealthy_python_goes_missing(python_dir):
+    prefix, tmpdir = python_dir
+
+    python.install_environment(prefix, C.DEFAULT, ())
+
+    exe_name = 'python' if sys.platform != 'win32' else 'python.exe'
+    py_exe = prefix.path(python.bin_dir('py_env-default'), exe_name)
+    os.remove(py_exe)
+
+    assert python.healthy(prefix, C.DEFAULT) is False
+
+
+def test_unhealthy_with_version_change(python_dir):
+    prefix, tmpdir = python_dir
+
+    python.install_environment(prefix, C.DEFAULT, ())
+
+    with open(prefix.path('py_env-default/pyvenv.cfg'), 'w') as f:
+        f.write('version_info = 1.2.3\n')
+
+    assert python.healthy(prefix, C.DEFAULT) is False
+
+
+def test_unhealthy_system_version_changes(python_dir):
+    prefix, tmpdir = python_dir
+
+    python.install_environment(prefix, C.DEFAULT, ())
+
+    with open(prefix.path('py_env-default/pyvenv.cfg'), 'a') as f:
+        f.write('base-executable = /does/not/exist\n')
+
+    assert python.healthy(prefix, C.DEFAULT) is False
+
+
+def test_unhealthy_old_virtualenv(python_dir):
+    prefix, tmpdir = python_dir
+
+    python.install_environment(prefix, C.DEFAULT, ())
+
+    # simulate "old" virtualenv by deleting this file
+    os.remove(prefix.path('py_env-default/pyvenv.cfg'))
 
-        assert python.healthy(prefix, C.DEFAULT) is False
+    assert python.healthy(prefix, C.DEFAULT) is False
diff --git a/tests/repository_test.py b/tests/repository_test.py
index 3c7a637..2ac7886 100644
--- a/tests/repository_test.py
+++ b/tests/repository_test.py
@@ -33,7 +33,7 @@ from testing.util import cwd
 from testing.util import get_resource_path
 from testing.util import skipif_cant_run_docker
 from testing.util import skipif_cant_run_swift
-from testing.util import xfailif_no_venv
+from testing.util import xfailif_windows
 from testing.util import xfailif_windows_no_ruby
 
 
@@ -163,7 +163,6 @@ def test_python_hook_weird_setup_cfg(in_git_dir, tempdir_factory, store):
     )
 
 
-@xfailif_no_venv
 def test_python_venv(tempdir_factory, store):  # pragma: no cover (no venv)
     _test_hook_repo(
         tempdir_factory, store, 'python_venv_hooks_repo',
@@ -243,6 +242,7 @@ def test_run_a_node_hook(tempdir_factory, store):
     )
 
 
+@xfailif_windows  # pragma: win32 no cover
 def test_run_a_node_hook_default_version(tempdir_factory, store):
     # make sure that this continues to work for platforms where node is not
     # installed at the system
@@ -252,6 +252,7 @@ def test_run_a_node_hook_default_version(tempdir_factory, store):
         test_run_a_node_hook(tempdir_factory, store)
 
 
+@xfailif_windows  # pragma: win32 no cover
 def test_run_versioned_node_hook(tempdir_factory, store):
     _test_hook_repo(
         tempdir_factory, store, 'node_versioned_hooks_repo',
@@ -534,6 +535,7 @@ def test_additional_ruby_dependencies_installed(tempdir_factory, store):
         assert 'tins' in output
 
 
+@xfailif_windows  # pragma: win32 no cover
 def test_additional_node_dependencies_installed(tempdir_factory, store):
     path = make_repo(tempdir_factory, 'node_hooks_repo')
     config = make_config_from_repo(path)
@@ -880,7 +882,7 @@ def test_manifest_hooks(tempdir_factory, store):
         require_serial=False,
         stages=(
             'commit', 'merge-commit', 'prepare-commit-msg', 'commit-msg',
-            'manual', 'post-checkout', 'push',
+            'post-commit', 'manual', 'post-checkout', 'push',
         ),
         types=['file'],
         verbose=False,
diff --git a/tests/store_test.py b/tests/store_test.py
index 5866616..6a4e900 100644
--- a/tests/store_test.py
+++ b/tests/store_test.py
@@ -25,7 +25,8 @@ def test_our_session_fixture_works():
 def test_get_default_directory_defaults_to_home():
     # Not we use the module level one which is not mocked
     ret = _get_default_directory()
-    assert ret == os.path.join(os.path.expanduser('~/.cache'), 'pre-commit')
+    expected = os.path.realpath(os.path.expanduser('~/.cache/pre-commit'))
+    assert ret == expected
 
 
 def test_adheres_to_xdg_specification():
@@ -33,7 +34,8 @@ def test_adheres_to_xdg_specification():
         os.environ, {'XDG_CACHE_HOME': '/tmp/fakehome'},
     ):
         ret = _get_default_directory()
-        assert ret == os.path.join('/tmp/fakehome', 'pre-commit')
+    expected = os.path.realpath('/tmp/fakehome/pre-commit')
+    assert ret == expected
 
 
 def test_uses_environment_variable_when_present():
@@ -41,7 +43,8 @@ def test_uses_environment_variable_when_present():
         os.environ, {'PRE_COMMIT_HOME': '/tmp/pre_commit_home'},
     ):
         ret = _get_default_directory()
-        assert ret == '/tmp/pre_commit_home'
+    expected = os.path.realpath('/tmp/pre_commit_home')
+    assert ret == expected
 
 
 def test_store_init(store):
diff --git a/tox.ini b/tox.ini
index d9f9420..63a3aab 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,7 +8,6 @@ commands =
     coverage erase
     coverage run -m pytest {posargs:tests}
     coverage report
-    pre-commit install
 
 [testenv:pre-commit]
 skip_install = true