A cross between 'git stash create' and 'git stash push --include-untracked'?

Alexander Shpilkin· Mar 30, 2025, 14:37 UTC · lore

Hi,

I'm trying to write a script for my use that would run before every invocation of 'make' and record the working tree state at that point. Stripping out the boring parts, it is basically just

    git update-ref --create-reflog refs/build $(git stash create)

but the problem is that what I want is less like 'git stash create' and more like 'git stash create --include-untracked', in case there are any new and as yet untracked source files that are nevertheless picked up by the build system.

Of course, that does not exist and, because of the syntax of 'git stash create', cannot exist. I've looked at the code in builtin/stash.c and it looks like there are only two callers of do_create_stash(): one is create_stash() and hardcodes the include_untracked argument to zero, the other is do_push_stash() and (assuming I try to undo its effects with 'git stash pop' afterwards) will potentially destroy my working tree's mtimes and cause more rebuilding than necessary. So it seems like I'm stuck here.

Any suggestions?

-- 
Thanks,
Alex

Patrick Steinhardt· Mar 31, 2025, 07:47 UTC · re: Alexander Shpilkin · lore

Re: A cross between 'git stash create' and 'git stash push --include-untracked'?

On Sun, Mar 30, 2025 at 05:37:42PM +0300, Alexander Shpilkin wrote:

Show 21 quoted lines

> Hi,
> 
> I'm trying to write a script for my use that would run before every
> invocation of 'make' and record the working tree state at that point. 
> Stripping out the boring parts, it is basically just
> 
>     git update-ref --create-reflog refs/build $(git stash create)
> 
> but the problem is that what I want is less like 'git stash create' and
> more like 'git stash create --include-untracked', in case there are any
> new and as yet untracked source files that are nevertheless picked up
> by the build system.
> 
> Of course, that does not exist and, because of the syntax of 'git stash
> create', cannot exist.  I've looked at the code in builtin/stash.c and
> it looks like there are only two callers of do_create_stash(): one is
> create_stash() and hardcodes the include_untracked argument to zero,
> the other is do_push_stash() and (assuming I try to undo its effects
> with 'git stash pop' afterwards) will potentially destroy my working
> tree's mtimes and cause more rebuilding than necessary.  So it seems
> like I'm stuck here.

Indeed.

> Any suggestions?

I guess the obvious answer here is to extend `git stash create` so that it knows to handle "--include-untracked".

Unfortunately, it wouldn't be quite as simple as just wiring up the command line option and passing the flag to `do_create_stash()` because `save_untracked_files()` saves untracked files by modifying the repository's index. Consequentially, we would still end up modifying the repository, even though the checked out files would ultimately remain unmodified.

I think we'd have to teach `save_untracked_files()` to do the changes on an in-memory index instead of invoking git-update-index(1). And if it knew to do that we could easily wire it up for `git stash create` and thus implement your usecase.

I won't be working on this myself as I'm short on time, but I assume that patches would very much be welcome.

Thanks!

Patrick