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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Pre-commit fails for git \u003e=2.25 if repo is on a Windows subst drive","articleBody":"Cross reference for another issue with same apparent root cause: https://github.com/microsoft/vscode/issues/100274#issuecomment-646499795\r\n\r\nIssue observed with pre-commit==2.7.1 and git 2.27.\r\nIssue resolved with downgrading git to 2.21 (I only have access to certain versions on my work machine).\r\n\r\nSteps to recreate for pre-commit (some taken from the above cross-reference):\r\n\r\n- Install git \u003e= 2.25 on Windows\r\n\r\n- Create a subst drive (`mkdir C:\\subst_dir \u0026\u0026 subst Z: C:\\subst_dir`)\r\n\r\n- Create a git repo in there (`mkdir Z:\\repo \u0026\u0026 cd /d Z:\\repo \u0026\u0026 git init`)\r\n\r\n- Add some python code, configure pre-commit, and run pre-commit.\r\n\r\nFailure observed: `An unexpected error has occurred: ValueError: path is on mount 'Z:', start on mount 'C:'`\r\n\r\nDiagnosis - it appears that the use of `git rev-parse --show-toplevel` in `pre_commit.main.get_root()` is suffering the same issue as seen in cross-referenced ticket; git will \"see through\" the subst command and rather than return a path on the subst-defined Z: drive, it will return the path from the C: drive. With this, after `pre_commit.main._adjust_args_and_chdir()` calls `pre_commit.main.get_root()` and does a chdir to the returned location, the following call to `os.path.relpath(args.config)` then fails with the ValueError as above, because it sees the path to the config file being on `Z:` but the current location being on `C:`.\r\n\r\nAfraid I don't have a suggested resolution but wanted to flag this up. I'm not too familiar with Windows systems and I'm a long way from Admin access on my work machine so opportunities for testing are limited; this was discovered as my scratch space for repos is a subst drive.\r\n","author":{"url":"https://github.com/jcameron73","@type":"Person","name":"jcameron73"},"datePublished":"2020-09-22T16:56:17.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":5},"url":"https://github.com/1610/pre-commit/issues/1610"}