From: Junio C Hamano <gitster@pobox.com>
To: "Michał Kępień" <michal@isc.org>
Cc: git@vger.kernel.org
Subject: Re: [PATCH 1/2] diff: add -I<regex> that ignores matching changes
Date: Wed, 07 Oct 2020 13:08:12 -0700 [thread overview]
Message-ID: <xmqqft6p240j.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <20201007194821.GA20549@larwa.hq.kempniu.pl> ("Michał Kępień"'s message of "Wed, 7 Oct 2020 21:48:21 +0200")
Michał Kępień <michal@isc.org> writes:
>> cannot be memset(0) before use? It seems like a much better
>> approach to ensure that we clear the structure.
>
> I do not know of any reason for xpparam_t structures to not be
> zero-initialized. In fact, they _are_ zero-initialized most of the
> time; AFAICT, there are just three places in the tree in which they are
> not.
>
> Would you like me to address that in a separate patch in this patch
> series?
Yes, as a preliminary clean-up patch before the real/fun stuff ;-)
>> > +-I<regex>::
>> > + Ignore changes whose all lines match <regex>.
>> > +
>>
>> The implementation seems to allow only one regex, but I suspect we'd
>> want to mimic
>>
>> $ printf "%s\n" a a a >test_a
>> $ printf "%s\n" b b b >test_b
>> $ diff -Ia test_a test_b
>> $ diff -Ib test_a test_b
>> $ diff -Ia -Ib test_a test_b
>
> Ah, sure. After skimming through various man pages available online, I
> was not sure whether all standalone versions of diff which support -I
> allow that switch to be used multiple times and I thought it would be
> better to start with the simplest thing possible. If you would rather
> have the above implemented immediately, I can sure try that in v2.
>
>> and until that happens, the explanation needs to say something about
>> earlier <regex> being discarded when this option is given more than
>> once.
>
> Sorry, where do I look for that explanation?
You wrote "Ignore changes whose all lines match <regex>"; I was
suggesting that we also need "when given more than once, all but the
last <regex> are ignored" after that sentence, because that is not
what people who know how -I works in versions of "diff" that support
it expect.
But I think it should be trivial to make it a list of patterns and
try to match against them in a loop. So let's support multiple
patterns from the get-go.
> I have not thought about this approach before, but it sounds elegant to
> me, at least at first glance - option parsing code sounds like the right
> place for sanitizing user-provided parameters. Doubly so if we take the
> multiple -I options approach. I will try this in v2.
Sounds good.
>> I agree with what you said in the cover letter that it would be a
>> good idea to name the existing xdl_mark_ignorable() and the new one
>> in such a way that they look similar and parallel, by renaming the
>> former to xdl_mark_ignorable_lines or something.
>
> Then I will do that in v2. Separate patch?
Given that the function has only one caller, I think it is better
done within the same patch. xdl_mark_ignorable() as the name of the
function is not wrong per-se, so it does not deserve to be renamed
standalone in a preliminary clean-up patch---there is nothing to be
cleaned up. The fact that we introduce a similarly tasked function
makes its current name less desirable, so adjusting to the new world
order is better done as part of the same patch.
> My pleasure ;-) And thanks for taking a look. Sorry about the long
> turnaround time, but unfortunately this is the best I can do at the
> moment.
Pleasure is mutual ;-)
We've survived without -I for 15 years. Even a few more months
would not hurt anybody. Take time, aim for a quality job, and most
importantly, have fun.
Thanks.
next prev parent reply other threads:[~2020-10-07 20:08 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-01 12:06 [PATCH 0/2] diff: add -I<regex> that ignores matching changes Michał Kępień
2020-10-01 12:06 ` [PATCH 1/2] " Michał Kępień
2020-10-01 18:21 ` Junio C Hamano
2020-10-07 19:48 ` Michał Kępień
2020-10-07 20:08 ` Junio C Hamano [this message]
2020-10-01 12:06 ` [PATCH 2/2] t: add -I<regex> tests Michał Kępień
2020-10-01 17:02 ` [PATCH 0/2] diff: add -I<regex> that ignores matching changes Junio C Hamano
2020-10-12 9:17 ` [PATCH v2 0/3] " Michał Kępień
2020-10-12 9:17 ` [PATCH v2 1/3] merge-base, xdiff: zero out xpparam_t structures Michał Kępień
2020-10-12 11:14 ` Johannes Schindelin
2020-10-12 17:09 ` Junio C Hamano
2020-10-12 19:52 ` Junio C Hamano
2020-10-13 6:35 ` Michał Kępień
2020-10-12 9:17 ` [PATCH v2 2/3] diff: add -I<regex> that ignores matching changes Michał Kępień
2020-10-12 11:20 ` Johannes Schindelin
2020-10-12 20:00 ` Junio C Hamano
2020-10-12 20:39 ` Johannes Schindelin
2020-10-12 21:43 ` Junio C Hamano
2020-10-13 6:37 ` Michał Kępień
2020-10-13 15:49 ` Junio C Hamano
2020-10-13 6:36 ` Michał Kępień
2020-10-13 12:02 ` Johannes Schindelin
2020-10-13 15:53 ` Junio C Hamano
2020-10-13 18:45 ` Michał Kępień
2020-10-12 18:01 ` Junio C Hamano
2020-10-13 6:38 ` Michał Kępień
2020-10-12 20:04 ` Junio C Hamano
2020-10-13 6:38 ` Michał Kępień
2020-10-12 9:17 ` [PATCH v2 3/3] t: add -I<regex> tests Michał Kępień
2020-10-12 11:49 ` Johannes Schindelin
2020-10-13 6:38 ` Michał Kępień
2020-10-13 12:00 ` Johannes Schindelin
2020-10-13 16:00 ` Junio C Hamano
2020-10-13 19:01 ` Michał Kępień
2020-10-15 11:45 ` Johannes Schindelin
2020-10-15 7:24 ` [PATCH v3 0/2] diff: add -I<regex> that ignores matching changes Michał Kępień
2020-10-15 7:24 ` [PATCH v3 1/2] merge-base, xdiff: zero out xpparam_t structures Michał Kępień
2020-10-15 7:24 ` [PATCH v3 2/2] diff: add -I<regex> that ignores matching changes Michał Kępień
2020-10-16 15:32 ` Phillip Wood
2020-10-16 18:04 ` Junio C Hamano
2020-10-19 9:48 ` Michał Kępień
2020-10-16 18:16 ` Junio C Hamano
2020-10-19 9:55 ` Michał Kępień
2020-10-19 17:29 ` Junio C Hamano
2020-10-16 10:00 ` [PATCH v3 0/2] " Johannes Schindelin
2020-10-20 6:48 ` [PATCH v4 " Michał Kępień
2020-10-20 6:48 ` [PATCH v4 1/2] merge-base, xdiff: zero out xpparam_t structures Michał Kępień
2020-10-20 6:48 ` [PATCH v4 2/2] diff: add -I<regex> that ignores matching changes Michał Kępień
2021-02-05 14:13 ` [PATCH 1/2] diff: add an API for deferred freeing Ævar Arnfjörð Bjarmason
2021-02-10 16:00 ` Johannes Schindelin
2021-02-11 3:00 ` Ævar Arnfjörð Bjarmason
2021-02-11 9:40 ` Johannes Schindelin
2021-02-11 10:21 ` Jeff King
2021-02-11 10:45 ` [PATCH v2 0/2] " Ævar Arnfjörð Bjarmason
2021-02-11 10:45 ` [PATCH v2 1/2] " Ævar Arnfjörð Bjarmason
2021-02-11 10:45 ` [PATCH v2 2/2] diff: plug memory leak from regcomp() on {log,diff} -I Ævar Arnfjörð Bjarmason
2021-02-05 14:13 ` [PATCH " Ævar Arnfjörð Bjarmason
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=xmqqft6p240j.fsf@gitster.c.googlers.com \
--to=gitster@pobox.com \
--cc=git@vger.kernel.org \
--cc=michal@isc.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).