Re: [PATCH] worktree repair: detect relative path in .git file correctly

[Junio C Hamano <gitster@pobox.com>]

"Yoichi NAKAYAMA via GitGitGadget" <gitgitgadget@gmail.com> writes:

> From: Yoichi NAKAYAMA <yoichi.nakayama@gmail.com>
>
> Since read_gitfile_gently() always returns an absolute path, the
> conversion from a relative path to an absolute path was not
> functioning and dead code existed.

This is ugly.  What problem is this really fixing?  What "conversion
from a relative path to an absolute path" does the above refer to?
What "dead code"?  Where in what file and what function?  Why does
the caller even care if it is absolute or relative?  Shouldn't they
work equally well as long as they point at the right location?

The proposed log message hides so many details to evaluate the claim
that this is a good change, and raises many unanswered questions.

Yes, read_gitfile_gently() always turns the gitfile it reads into an
absolute form.  Is there a caller A that wants the underlying
relative form, and if so why?  Is it to compare with some other path
that is relative?  How did the code B obtained the other path to be
compared that is relative?  If that code B used the helper that is
different from read_gitfile_gently() to obtain the other path that
is relative, perhaps the caller A can be changed to call it instead
of calling read_gitfile_gently() and the fix can be done without
churning so many existing call sites?

Stepping back a bit, why does "repair" even care if it is relative?
Is it considered a semi-error when a gitfile records its target as a
relative path?  If so, I wonder if a cleaner way may be to add a new
READ_GITFILE_ERR_RELATIVE_PATH constant that is treated as non-fatal
error by the read_gitfile_error_die() function?  If that approach
works, that may be the cleanest, as I suspect that "was it recorded
as an absolute path?" will not stay to be the only special case in
niche applications like "repair", but we need to audit callers of
the _gently() function and make sure they do not barf with the new
return code.

If not, perhaps introduce a separate function that returns the path
it read without any conversion, i.e.,

    char *read_raw_gitfile(const char *path);

that "repair" thing can use, and have it do the relateve-to-absolute
converaion itself, perhaps?  That function would be created by moving
most of the code from read_gitfile_gently() and read_gitfile_gently()
would become a very thin wrapper around that function.  Wouldn't that
be the least invasive and cleanest solution, if it works?

Thanks.