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From: Junio C Hamano <>
Subject: Re: [PATCH v4 1/1] MacOS: precompose_argv_prefix()
Date: Wed, 03 Feb 2021 14:13:53 -0800
Message-ID: <> (raw)
In-Reply-To: <> (Junio C. Hamano's message of "Wed, 03 Feb 2021 11:33:00 -0800")

Junio C Hamano <> writes:

> Just as the prefix-less variant was idempotent and that was the
> reason why cmd_diff_files() had its own precompose() even if the
> incoming argv[] is supposed to be already precomposed because it
> was processed in another call to precompose() in run_builtin(),
> this patch keeps these seemingly redundant calls, because it is not
> meant as a clean-up but as a bugfix for the prefix part.
> OK. ... Ah, no, the call in run_builtin() is a new thing.  We didn't
> have it, and the redundant call is what this patch introduced, so
> we need to be a bit more careful about the analysis here.  It is one
> thing to say "we leave the existing iffy code and address only a
> single bug" and do so.  It is entirely different to say so and then
> do "we introduce an iffy code and address only a single bug".  We
> need to admit that what we added _is_ iffy but supposed to be safe.
> Just saying "it is supposed to be safe" without saying why it is
> iffy is dishonest and does not help future developers who may want
> to jump in and clean the code.
> Perhaps
> 	Now add it into git.c::run_builtin() as well.  Existing
> 	precompose calls in diff-files.c and others would become
> 	redundant but because we do not want to make sure that there
> 	is no way for the control to reach them without passing
> 	run_builtin(), we'll keep them in place just in case.  The
> 	calls to precompose() are idempotent so it should not hurt.
> or something?

FYI, I've tweaked the proposed log message like the following before
queuing.  I think that would be explicit enough to remind us that we
may be able to improve the situation fairly easily.


1:  071dfe8793 ! 1:  5c327502db MacOS: precompose_argv_prefix()
    @@ Commit message
         The original patch for preocomposed unicode, 76759c7dff53, placed
         precompose_argv() into parse-options.c
    -    Now add it into git.c (as well) for commands that don't use parse-options.
    -    Note that precompose() may be called twice - it is idempotent.
    +    Now add it into git.c::run_builtin() as well.  Existing precompose
    +    calls in diff-files.c and others may become redundant, and if we
    +    audit the callflows that reach these places to make sure that they
    +    can never be reached without going through the new call added to
    +    run_builtin(), we might be able to remove these existing ones.
    +    But in this commit, we do not bother to do so and leave these
    +    precompose callsites as they are.  Because precompose() is
    +    idempotent and can be called on an already precomposed string
    +    safely, this is safer than removing existing calls without fully
    +    vetting the callflows.
         There is certainly room for cleanups - this change intends to be a bug fix.
         Cleanups needs more tests in e.g. t/, and should

  reply	other threads:[~2021-02-03 22:16 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-06 11:35 git-bugreport-2021-01-06-1209.txt (git can't deal with special characters) Daniel Troger
2021-01-06 14:21 ` Torsten Bögershausen
2021-01-06 16:49   ` Daniel Troger
2021-01-06 21:47     ` Torsten Bögershausen
2021-01-06 22:21       ` Daniel Troger
2021-01-06 23:07         ` Randall S. Becker
2021-01-07 14:34           ` Philippe Blain
2021-01-07 15:49             ` Torsten Bögershausen
2021-01-07 16:21               ` Philippe Blain
2021-01-08 19:07                 ` Torsten Bögershausen
2021-01-24 15:13 ` [PATCH/RFC v1 1/1] git restore -p . and precomposed unicode tboegi
2021-01-24 19:51   ` Junio C Hamano
2021-01-25 16:53     ` Torsten Bögershausen
2021-01-29 17:15 ` [PATCH v2 1/1] MacOS: precompose_argv_prefix() tboegi
2021-01-29 23:19   ` Junio C Hamano
2021-01-31  0:43   ` Junio C Hamano
2021-01-31  9:50     ` Torsten =?unknown-8bit?Q?B=C3=B6gershausen?=
2021-02-02 15:11 ` [PATCH v3 " tboegi
2021-02-02 17:43   ` Junio C Hamano
2021-02-03 16:28 ` [PATCH v4 " tboegi
2021-02-03 19:33   ` Junio C Hamano
2021-02-03 22:13     ` Junio C Hamano [this message]
2021-02-05 17:31       ` Torsten Bögershausen

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