Vendored crate with git submodule may have something wrong with gitignore about cargo HOT 1 OPEN

Sorry for the late response.

This is an interesting case! Let me tell what happen.

In jemalloc, they have a .gitignore rule excluding everything under /test/stress/[A-Za-z]*. I believe this will exclude also directories, which you cannot use negate pattern to re-include files (according to gitignore specification)

/test/stress/[A-Za-z]*
!/test/stress/[A-Za-z]*.*

From my observation, cargo vendor successfully copied over vendor-issue-reproduce/vendor/is_odd/jemalloc/test/stress/cpp/microbench.cpp into the vendor directory. However, when git clean -dfqx was run, since the vendor-issue-reproduce/vendor/is_odd/jemalloc was no longer a git submodule, Cargo lost the git index information, so the file was clean because the .gitignore in jemalloc was not able to re-include.

I don't feel like this is a bug in Cargo, as we intentionally flatten the repo and remove git information when vendoring, so Cargo doesn't need to clobber user's gitconfig. However, since this situation, a file is re-added even was gitignored, is not uncommon, I am open to ideas making it more reasonable.

from cargo.