The vcs.useIgnoreFile option doesn't match git ignore behavior

[BoltsJ]

I was setting up an existing project and was wondering: is it expected behavior that this option works different than git ignore? I make use of .git/info/exclude quite a bit to exclude local configuration for tools that I'm using that aren't standard for the whole team. My expectation was that vcs.useIgnoreFile would mostly match git's behavior¹ for exclusion.

If this is intended behavior, I think it would be worthwhile to call out in the docs that only the .gitignore files are read, but I would love if all applicable files are read based on the same rules that git is using, which does seem to be supported by the ignore crate.

Footnotes

1. https://git-scm.com/docs/gitignore ↩

[ematipico]

Biome uses only the ignore files. If you think our documentation isn't clear enough, please send a PR to better clarify it :)

[BoltsJ]

Yeah, I can look at sending a doc update later this week. I guess my confusion stems from .git/info/exclude and $XDG_CONFIG_HOME/git/ignore also being vcs ignore files, but not getting read by biome. I see in the source code that .ignore files are also read, so I can use that as a workaround, at least for now. Not that I have the rust expertise to do it myself right now, but is changing the behavior to respect those files a change that would be considered for inclusion?

[ematipico]

Under the hood, we use this crate to handle gitignore matches, which would allow us to use a home ignore file too: https://docs.rs/ignore/latest/ignore/gitignore/struct.Gitignore.html#method.global

However, I think we should check the home directory only with a new option, opt-in, because it might create false positives/negatives in projects shared by multiple people.

It seems that the crate doesn't support .git/info/exclude. I'm not sure how .git/info/exclude works but we might be able to make it working.

[BoltsJ]

It does make sense to not use the global file by default, since unlike git itself, biome doesn't negate ignoring tracked files, and I don't think the ignore crate supports that logic.

.git/info/exclude is a regular file with the same format as .gitignore, so it should be enough to add it to the read ignore files. In fact, my workaround is to symlink the .git/info/exclude file to .ignore so that biome reads it. It's essentially a machine-local .gitignore for a repository. The crate also supports it via the Walk struct, but that also bring in the global file.

[medmunds]

One option is to ask git itself whether it thinks a particular file should be ignored, via git check-ignore. That's guaranteed to pay attention to all the global excludes and repo-level ignore files git uses, by definition.

It supports a streaming mode where you can blast a list of paths at its stdin and it provides the status of each on stdout in the same order. (Here's an example doing that in Python.)

(I was similarly confused that vcs.useIgnoreFile does not mean "use git ignore logic" and found my way here.)

[olejorgenb]

Seems to have been implemented: #4822 🎉