From 3a3fe94760488e3e5d9f2f873194fa54c613eaf0 Mon Sep 17 00:00:00 2001
From: marsha <46257533+m-rsha@users.noreply.github.com>
Date: Sun, 30 Oct 2022 18:23:55 -0500
Subject: [PATCH] Add `relpath` test for Windows error coverage

---
 pre_commit/main.py | 8 ++++----
 tests/main_test.py | 7 +++++++
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/pre_commit/main.py b/pre_commit/main.py
index 4ecee41b..70f3d43a 100644
--- a/pre_commit/main.py
+++ b/pre_commit/main.py
@@ -165,14 +165,14 @@ def _adjust_args_and_chdir(args: argparse.Namespace) -> None:
     toplevel = git.get_root()
     os.chdir(toplevel)
 
+    # https://github.com/pre-commit/pre-commit/issues/2530
+    # `os.relpath` raises a ValueError on Windows when the paths given are on
+    # separate drives.
     try:
         args.config = os.path.relpath(args.config)
-    # https://github.com/pre-commit/pre-commit/issues/2530
-    # os.relpath will fail with a ValueError if the two directories are on
-    # two different drives on Windows and since the path is made relative
-    # for display purposes only we can ignore the error
     except ValueError:
         pass
+
     if args.command in {'run', 'try-repo'}:
         args.files = [os.path.relpath(filename) for filename in args.files]
         if args.commit_msg_filename is not None:
diff --git a/tests/main_test.py b/tests/main_test.py
index 51159262..4daa0690 100644
--- a/tests/main_test.py
+++ b/tests/main_test.py
@@ -27,6 +27,13 @@ def test_adjust_args_and_chdir_not_in_git_dir(in_tmpdir):
         main._adjust_args_and_chdir(_args())
 
 
+def test_adjust_args_and_chdir_relpath_to_different_drive():
+    args = _args(command='run', files=['f1', 'f2'])
+    with mock.patch.object(os.path, 'relpath', side_effect=ValueError):
+        with pytest.raises(ValueError):
+            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)