Re: [PATCH v4 4/4] submodule: fix case-folding gitdir filesystem colisions

From: Adrian Ratiu <adrian.ratiu@collabora.com>
Date: Nov 10, 2025, 17:11 UTC
Message-ID: <87ecq5ke2m.fsf@gentoo.mail-host-address-is-not-set>
In-Reply-To: <20251108T182050Z.vbNv4y2kizC1@fnord.qqx.org>

On Sat, 08 Nov 2025, Aaron Schrab <aaron@schrab.com> wrote:

Show 14 quoted lines

> At 17:05 +0200 07 Nov 2025, Adrian Ratiu 
> <adrian.ratiu@collabora.com> wrote: 
>>Add a new check in validate_submodule_git_dir() to detect and 
>>prevent case-folding filesystem colisions. When this new check 
>>is triggered, a stricter casefolding aware URI encoding is used 
>>to percent-encode uppercase characters, e.g. Foo becomes %46oo. 
>>By using this check/retry mechanism the uppercase encoding is 
>>only applied when necessary, so case-sensitive filesystems are 
>>not affected. 
> 
> What happens if `Foo` is added first and doesn't conflict with 
> anything,  then later a new submodule is added which would 
> naturally get the name  `foo` which would conflict and doesn't 
> have any upper case characters to  encode to avoid the conflict?

What an excellent question. Thank you!

Right now, in v4, in this case the user adding the second `foo` module will have to manually set the submodule.foo.gitdir config to avoid the conflict, because Foo already uses the coliding path.

I can add a test specifically for this edge case to exercise config overrides on case-folding file-systems conflicts.

OR...

Maybe we could derive a new path automatically (eg foo2 or foo_, suggestions welcome) and use it if valid. This way, there is no user intervention.

Do you have any preference?

Thanks again, Adrian