Re: [PATCH v5 1/2] setup: distingush ENOENT from other stat errors

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 18, 2026, 18:43 UTC
Message-ID: <xmqqpl617uzz.fsf@gitster.g>
In-Reply-To: <xmqqy0kp7wai.fsf@gitster.g>

Junio C Hamano <gitster@pobox.com> writes:

Show 15 quoted lines

> Tian Yuchen <a3205153416@gmail.com> writes:
>
>> Currently, 'read_gitfile_gently()' treats all 'stat()' failures as
>> generic errors. This prevents distinguishing between a missing file and
>> real errors like permission denied (fatal).
>
> The above plan makes sense---you would split stat() error into two
> different classes, start returning ERR_STAT_NOENT in addition to
> ERR_STAT_FAILED, have the caller act on the new ERR_STAT_NOENT and
> adjust the way it acts on ERR_STAT_FAILED, and if possible add tests
> to make sure we react to failures from stat in an appropriate way
> (but how? --- it is where my "if possible" comes from).  So I would
> expect that the other patch would be to split ERR_NOT_A_FILE and add
> ERR_IS_A_DIR, have the caller act on the new ERR_IS_A_DIR and adjust
> the way it acts on ERR_NOT_A_FILE.

I forgot to say one thing.

When changing the external interface for these service functions like read_gitfile_gently() and read_gitfile_error_die(), we need to make sure the change will not break _other_ callers of them, outside our main focus area. The latter, for example, has a caller in submodule.c and we need to make sure that the existing code is reacting to the updated definition of what ERR_STAT_FAILED and ERR_NOT_A_FILE mean (and if not, adjust it). read_gitfile_gently() is used more widely outside setup.c and we need to audit these callers, too.