1 files changed, 46 insertions, 20 deletions

diff --git a/pre_commit/git.py b/pre_commit/git.py
index e9ec601..35392b3 100644
--- a/pre_commit/git.py
+++ b/pre_commit/git.py
@@ -1,11 +1,9 @@
+from __future__ import annotations
+
 import logging
 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
@@ -18,7 +16,7 @@ logger = logging.getLogger(__name__)
 NO_FS_MONITOR = ('-c', 'core.useBuiltinFSMonitor=false')
 
 
-def zsplit(s: str) -> List[str]:
+def zsplit(s: str) -> list[str]:
     s = s.strip('\0')
     if s:
         return s.split('\0')
@@ -27,8 +25,8 @@ def zsplit(s: str) -> List[str]:
 
 
 def no_git_env(
-        _env: Optional[MutableMapping[str, str]] = None,
-) -> Dict[str, str]:
+        _env: MutableMapping[str, str] | None = 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
@@ -45,6 +43,7 @@ def no_git_env(
         k in {
             'GIT_EXEC_PATH', 'GIT_SSH', 'GIT_SSH_COMMAND', 'GIT_SSL_CAINFO',
             'GIT_SSL_NO_VERIFY', 'GIT_CONFIG_COUNT',
+            'GIT_HTTP_PROXY_AUTHMETHOD',
         }
     }
 
@@ -58,13 +57,15 @@ def get_root() -> str:
         root = os.path.abspath(
             cmd_output('git', 'rev-parse', '--show-cdup')[1].strip(),
         )
-        git_dir = os.path.abspath(get_git_dir())
+        inside_git_dir = cmd_output(
+            'git', 'rev-parse', '--is-inside-git-dir',
+        )[1].strip()
     except CalledProcessError:
         raise FatalError(
             'git failed. Is it installed, and are you in a Git repository '
             'directory?',
         )
-    if os.path.samefile(root, git_dir):
+    if inside_git_dir != 'false':
         raise FatalError(
             'git toplevel unexpectedly empty! make sure you are not '
             'inside the `.git` directory of your repository.',
@@ -73,15 +74,25 @@ def get_root() -> str:
 
 
 def get_git_dir(git_root: str = '.') -> str:
-    opts = ('--git-common-dir', '--git-dir')
-    _, out, _ = cmd_output('git', 'rev-parse', *opts, cwd=git_root)
-    for line, opt in zip(out.splitlines(), opts):
-        if line != opt:  # pragma: no branch (git < 2.5)
-            return os.path.normpath(os.path.join(git_root, line))
+    opt = '--git-dir'
+    _, out, _ = cmd_output('git', 'rev-parse', opt, cwd=git_root)
+    git_dir = out.strip()
+    if git_dir != opt:
+        return os.path.normpath(os.path.join(git_root, git_dir))
     else:
         raise AssertionError('unreachable: no git dir')
 
 
+def get_git_common_dir(git_root: str = '.') -> str:
+    opt = '--git-common-dir'
+    _, out, _ = cmd_output('git', 'rev-parse', opt, cwd=git_root)
+    git_common_dir = out.strip()
+    if git_common_dir != opt:
+        return os.path.normpath(os.path.join(git_root, git_common_dir))
+    else:  # pragma: no cover (git < 2.5)
+        return get_git_dir(git_root)
+
+
 def get_remote_url(git_root: str) -> str:
     _, out, _ = cmd_output('git', 'config', 'remote.origin.url', cwd=git_root)
     return out.strip()
@@ -95,7 +106,7 @@ def is_in_merge_conflict() -> bool:
     )
 
 
-def parse_merge_msg_for_conflicts(merge_msg: bytes) -> List[str]:
+def parse_merge_msg_for_conflicts(merge_msg: bytes) -> list[str]:
     # Conflicted files start with tabs
     return [
         line.lstrip(b'#').strip().decode()
@@ -105,7 +116,7 @@ def parse_merge_msg_for_conflicts(merge_msg: bytes) -> List[str]:
     ]
 
 
-def get_conflicted_files() -> Set[str]:
+def get_conflicted_files() -> set[str]:
     logger.info('Checking merge-conflict files only.')
     # Need to get the conflicted files from the MERGE_MSG because they could
     # have resolved the conflict by choosing one side or the other
@@ -126,7 +137,7 @@ def get_conflicted_files() -> Set[str]:
     return set(merge_conflict_filenames) | set(merge_diff_filenames)
 
 
-def get_staged_files(cwd: Optional[str] = None) -> List[str]:
+def get_staged_files(cwd: str | None = None) -> list[str]:
     return zsplit(
         cmd_output(
             'git', 'diff', '--staged', '--name-only', '--no-ext-diff', '-z',
@@ -137,7 +148,7 @@ def get_staged_files(cwd: Optional[str] = None) -> List[str]:
     )
 
 
-def intent_to_add_files() -> List[str]:
+def intent_to_add_files() -> list[str]:
     _, stdout, _ = cmd_output(
         'git', 'status', '--ignore-submodules', '--porcelain', '-z',
     )
@@ -153,11 +164,11 @@ def intent_to_add_files() -> List[str]:
     return intent_to_add
 
 
-def get_all_files() -> List[str]:
+def get_all_files() -> list[str]:
     return zsplit(cmd_output('git', 'ls-files', '-z')[1])
 
 
-def get_changed_files(old: str, new: str) -> List[str]:
+def get_changed_files(old: str, new: str) -> list[str]:
     diff_cmd = ('git', 'diff', '--name-only', '--no-ext-diff', '-z')
     try:
         _, out, _ = cmd_output(*diff_cmd, f'{old}...{new}')
@@ -230,3 +241,18 @@ def check_for_cygwin_mismatch() -> None:
                 f' - python {exe_type[is_cygwin_python]}\n'
                 f' - git {exe_type[is_cygwin_git]}\n',
             )
+
+
+def get_best_candidate_tag(rev: str, git_repo: str) -> str:
+    """Get the best tag candidate.
+
+    Multiple tags can exist on a SHA. Sometimes a moving tag is attached
+    to a version tag. Try to pick the tag that looks like a version.
+    """
+    tags = cmd_output(
+        'git', *NO_FS_MONITOR, 'tag', '--points-at', rev, cwd=git_repo,
+    )[1].splitlines()
+    for tag in tags:
+        if '.' in tag:
+            return tag
+    return rev