From f75fc6b2a85a61e50a0270d24a3589a083f1c06c Mon Sep 17 00:00:00 2001
From: Anthony Sottile <asottile@umich.edu>
Date: Wed, 27 Jan 2021 10:08:48 -0800
Subject: [PATCH] fix execution in worktrees in subdirectories of bare
 repositories

---
 pre_commit/git.py  |  2 +-
 tests/git_test.py  | 20 ++++++++++++++++++++
 tests/main_test.py |  5 -----
 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/pre_commit/git.py b/pre_commit/git.py
index 50962745..bec816c9 100644
--- a/pre_commit/git.py
+++ b/pre_commit/git.py
@@ -61,7 +61,7 @@ def get_root() -> str:
             'git failed. Is it installed, and are you in a Git repository '
             'directory?',
         )
-    if os.path.commonpath((root, git_dir)) == git_dir:
+    if os.path.samefile(root, git_dir):
         raise FatalError(
             'git toplevel unexpectedly empty! make sure you are not '
             'inside the `.git` directory of your repository.',
diff --git a/tests/git_test.py b/tests/git_test.py
index fafd4a6e..69fd2067 100644
--- a/tests/git_test.py
+++ b/tests/git_test.py
@@ -3,6 +3,7 @@ import os.path
 import pytest
 
 from pre_commit import git
+from pre_commit.error_handler import FatalError
 from pre_commit.util import cmd_output
 from testing.util import git_commit
 
@@ -18,6 +19,25 @@ def test_get_root_deeper(in_git_dir):
         assert os.path.normcase(git.get_root()) == expected
 
 
+def test_in_exactly_dot_git(in_git_dir):
+    with in_git_dir.join('.git').as_cwd(), pytest.raises(FatalError):
+        git.get_root()
+
+
+def test_get_root_bare_worktree(tmpdir):
+    src = tmpdir.join('src').ensure_dir()
+    cmd_output('git', 'init', str(src))
+    git_commit(cwd=str(src))
+
+    bare = tmpdir.join('bare.git').ensure_dir()
+    cmd_output('git', 'clone', '--bare', str(src), str(bare))
+
+    cmd_output('git', 'worktree', 'add', 'foo', 'HEAD', cwd=bare)
+
+    with bare.join('foo').as_cwd():
+        assert git.get_root() == os.path.abspath('.')
+
+
 def test_get_staged_files_deleted(in_git_dir):
     in_git_dir.join('test').ensure()
     cmd_output('git', 'add', 'test')
diff --git a/tests/main_test.py b/tests/main_test.py
index 6738df68..2460bd85 100644
--- a/tests/main_test.py
+++ b/tests/main_test.py
@@ -35,11 +35,6 @@ def test_adjust_args_and_chdir_not_in_git_dir(in_tmpdir):
         main._adjust_args_and_chdir(_args())
 
 
-def test_adjust_args_and_chdir_in_dot_git_dir(in_git_dir):
-    with in_git_dir.join('.git').as_cwd(), pytest.raises(FatalError):
-        main._adjust_args_and_chdir(_args())
-
-
 def test_adjust_args_and_chdir_noop(in_git_dir):
     args = _args(command='run', files=['f1', 'f2'])
     main._adjust_args_and_chdir(args)