(Windows) Panic during `git test` if `-x` script contains characters which are invalid in a file path

[rmvermeulen]

Description of the bug

Running a git test run ... where the script part contains e.g. : panics on Windows.
It seems the : is copied as-is into the filepath, and because it's Windows, that's not ok. On WSL it works fine.

Minimal reproduction

git test run main..HEAD -x 'echo :'

Expected behavior

I expected the script to run as usual, meaning I expect that the command will be converted to a valid path
before trying to make a new directory.

Actual behavior

While running git test main..HEAD -x 'pnpm check:prettier' I got the following output:

The application panicked (crashed).
Message:  A fatal error occurred:
   0: Failed waiting on workers
   1: Worker 1 failed when processing commit ec9d22ab59b5d0aca2679c8e5db19ddd07c5b34f: Creating command directory "D:/Projects/awpw-node/.git/branchless\\test\\13f2bb5e83b30b6b69add54247527753ed5c8ef1\\pnpm__run__check:prettier"

Version of rustc

rustc 1.88.0-nightly (2e6882ac5 2025-05-05)

Automated bug report

git-branchless-bug-report.txt

edit: typos

[claytonrcarter]

Thank you for reporting this. That error is originating here:
https://github.com/arxanas/git-branchless/blob/master/git-branchless-test/src/lib.rs#L2376-L2378

As you can see, we're "slugifying" the command (as passed to test -x), and trying to create a directory named by that slug. The slug fn is defined here:
https://github.com/arxanas/git-branchless/blob/master/git-branchless-lib/src/git/test.rs#L45-L47

The simplest fix for this issue would be to add ':' to the list of replaced chars in that fn. However, a more robust fix would probably replace/slugify the commands according to a platform specific list of chars to exclude, or to simply replace all non-aphanumeric chars. (I suspect that the latter would still give us a reasonable level of cache uniqueness.)

I took a stab at fixing this, but I couldn't reproduce the issue in a failing test. (I'm running on a mac, and : is a valid directory char¹.) I'm not going to pursue this further until someone can provide a failing test case for macos and/or linux, but I'm also open to a PR to fix it in a windows-only test case. (I don't have a Windows machine to play with.)

Ref: https://superuser.com/questions/617517/remove-all-illegal-characters-from-all-filenames-in-a-given-folder

Footnotes

1. To further confuse things, macOS Finder forbids you to name a folder w/ a :, but mkdir in the terminal doesn't care and the directory seems to work just fine. (In Finder, the directory is displayed as foo/bar.) ↩