From: "René Scharfe" <firstname.lastname@example.org>
To: "Ævar Arnfjörð Bjarmason" <email@example.com>,
"Junio C Hamano" <firstname.lastname@example.org>
Cc: email@example.com, "Michał Kępień" <firstname.lastname@example.org>
Subject: Re: [PATCH] diff: fix a segfault in >2 tree -I<regex> and --output=<file>
Date: Sat, 18 Jun 2022 13:12:13 +0200 [thread overview]
Message-ID: <email@example.com> (raw)
Am 24.05.22 um 22:17 schrieb Ævar Arnfjörð Bjarmason:
> On Tue, May 24 2022, Junio C Hamano wrote:
>> Ævar Arnfjörð Bjarmason <firstname.lastname@example.org> writes:
>>> I.e. the "right" thing to do in this case would require a much more
>>> involved fix. We've somehow ended up not supporting --output=<file>, -I
>>> and probably many other options in the combined-diff mode, which both in
>>> testing and in this part of the implementation seems to have become an
>> OK, a hopefully final question.
>> How much less involved is it to add a new code (without doing
>> anything in this patch)
> ...yeah, I think for this one it makes sense to narrowly focus on the
>> to detect and die on the combination of
>> combined-diff with these two options, so that we can document the
>> fact that we do not support them? It would give us much better way
>> forward than leaving the command silently ignore and give result
>> that is not in line with what was asked, wouldn't it? That way, the
>> much more involved "fix" will turn into a change to add a missing
> I think not much, it's rather trivial for the case where we invoke "git
> diff", I.e. just adding something to the "builtin_diff_combined()"
> branch in builtin/diff.c to detect these two cases specifically.
> I haven't looked in any depth into how we might reach code in
> combine-diff.c through other means, and if any of it can set these two
> indirectly somewhere else (i.e. other things that take diff options).
So let's add those checks there.
> I also wonder if I'm just wrong in my assessment that it's a Bad Thing
> that we take some of these without ever doing anything with them in some
> modes, e.g.:
> git log --oneline -I foo
> This will never do anything with that "-I foo" by definition, but would
> as soon as you add -p, should we error without -p (or other diff-showing
Which definition? The documentation says:
Ignore changes whose all lines match <regex>. This option may be specified more than once.
That sounds to me like it would affect history simplification, and thus
git log --oneline. (Which seems expensive, but that's a different
concern.) So based on that I'd expect at least a warning if -I is
> The same goes for range-diff, format-patch, --remerge-diff and any
> number of other things where we take the full set of options, but only
> do something with a limited subset of them.
> It is helpful in some cases if we were more anal about it, e.g. when I
> was wondering why -I didn't do anything with the combined diff, but also
> handy for scripting and one-liners if you can tweak the command-line
> back & forth without it being so strict.
> So I don't know. Maybe I'm just trying to talk myself out of pulling on
> that (bound to be long) thread, but I'm coming more around to this just
> being a non-issue beyond the narrow and needed fix for diff_free() in
> I.e. the more general approach of chasing down options that don't do
> anything for a given "diff mode". We might still want to error on some
> particular ones, such as -I with the combined diff (but not with
> --oneline, or whatever).
Supporting all combinations would be ideal. Reporting unsupported
combinations would be the next best thing. I wonder if we passed the
point of having so many options for e.g. git log that assessing all
of their pairings has become impractical, though. :-/
next prev parent reply other threads:[~2022-06-18 11:12 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-14 9:32 Bug: combined diff with --ignore-matching-lines René Scharfe
2022-05-23 18:31 ` [PATCH] diff: fix a segfault in >2 tree -I<regex> and --output=<file> Ævar Arnfjörð Bjarmason
2022-05-23 20:08 ` Junio C Hamano
2022-05-24 11:38 ` Ævar Arnfjörð Bjarmason
2022-05-24 19:38 ` Junio C Hamano
2022-05-24 20:17 ` Ævar Arnfjörð Bjarmason
2022-06-18 11:12 ` René Scharfe [this message]
2022-06-18 11:12 ` [PATCH 1/2] combine-diff: abort if --ignore-matching-lines is given René Scharfe
2022-06-21 15:35 ` Junio C Hamano
2022-06-21 15:58 ` René Scharfe
2022-06-21 16:55 ` Junio C Hamano
2022-06-18 11:12 ` [PATCH 2/2] combine-diff: abort if --output " René Scharfe
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