feat: Allow recursing into submodules when using git walker

[akshaymankar]

I haven't added tests, but I'll add if this feature is deemed desirable.

[brianmcgee]

Thanks for the PR!

I'm wondering if it might be better to allow passing through git args? 🤔

It would make it more general, and possibly help users to further customise their git behaviour in future.

@jfly @zimbatm thoughts?

[jfly]

I'm wondering if it might be better to allow passing through git args?

Coupling ourselves to the git cli smells wrong to me. We used to use a pure-go implementation of git, right? Wouldn't it be hard to switch back to that in the future if we supported arbitrary git cli args?

[brianmcgee]

I don't see us moving back to a git alternative; there is too much risk of feature drift/bugs like we experienced already.

[jfly]

That's fair. I personally am not anxious about being coupled to the git cli, either, but I do think it's worth acknowledging that it's different than just being coupled with git.

More concretely, what's your idea? Is it having the ability to pass arbitrary args to git ls-files?

[brianmcgee]

More concretely, what's your idea? Is it having the ability to pass arbitrary args to git ls-files?

Yeah. Straight pass through I guess.

[jfly]

Looking through git ls-files --help, I see that some of these flags affect the formatting of the output. For example, see -z:

-z
    \0 line termination on output and do not quote filenames. See OUTPUT below for more
    information.

I imagine this could break our parsing of the output of git ls-files, and result in some pretty weird behavior.

Are there any existing options/flags that treefmt has that wouldn't need to exist if we had this generic flags feature? Or on the flip side, do you see any useful flags people might want to use (besides the --recurse-submodules in this PR)?

[akshaymankar]

Makes me wonder if it is better to just create a separate walker which takes a command to get the list of files.

[jfly]

Oooh that's a neat idea, as it would allow people to use non-git vcs tools.

[brianmcgee]

I like this idea as well