git@vger.kernel.org mailing list mirror (one of many)
 help / Atom feed
From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Git Mailing List <git@vger.kernel.org>,
	Lars Hjemli <hjemli@gmail.com>, Jeff King <peff@peff.net>,
	Christian Couder <christian.couder@gmail.com>,
	Carlos Rica <jasampler@gmail.com>,
	Samuel Tardieu <sam@rfc1149.net>,
	Tom Grennan <tmgrennan@gmail.com>
Subject: Re: [PATCH 2/8] tag: Refactor the options handling code to be less bizarro
Date: Sat, 18 Mar 2017 20:13:12 +0100
Message-ID: <CACBZZX4Zs=00QXv5eaafQd8-n7OakcL3WeQh8XxiMo-9a+kAzQ@mail.gmail.com> (raw)
In-Reply-To: <xmqqr31u301u.fsf@gitster.mtv.corp.google.com>

On Sat, Mar 18, 2017 at 7:35 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Ævar Arnfjörð Bjarmason  <avarab@gmail.com> writes:
>
>> diff --git a/builtin/tag.c b/builtin/tag.c
>> index ad29be6923..0bba3fd070 100644
>> --- a/builtin/tag.c
>> +++ b/builtin/tag.c
>> @@ -454,10 +454,10 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
>>       }
>>       create_tag_object = (opt.sign || annotate || msg.given || msgfile);
>>
>> -     if (argc == 0 && !cmdmode)
>> +     if (argc == 0 && !cmdmode && !create_tag_object)
>>               cmdmode = 'l';
>
> So with this change, if we cannot infer that we are creating a tag
> object from other options, we leave cmdmode to its original 0.
>
>> -     if ((create_tag_object || force) && (cmdmode != 0))
>> +     if ((create_tag_object || force) && (cmdmode || (!cmdmode && !argc)))
>>               usage_with_options(git_tag_usage, options);
>
> And then immediately after that, we complain by detecting that we
> know we are creating a tag and a non-zero cmdmode is in effect
> (i.e. 'l', 'd' or 'v', none of which is about creating a tag).  The
> way we used to detect that we are doing something other than tag
> creation was by seeing cmdmode is set to anything.  Because of your
> earlier change, that no longer is true.  You need to separately
> check (!cmdmode && !argc).
>
> By following the logic that way, I can see how this change at this
> step is a no-op, but I have to say that the code with this patch
> looks much more bizarre than the original.
>
> I am not sure why you want to do the first change at this step in
> the first place.  Is it because you'd want to take over (!cmdmode &&
> !argc) condtion to default to 'list'?  With the change in 4/8 and
> 5/8, you are ensuring that cmdmode is set to 'l' for these new cases
> before the code hits the check to call usage_with_options().  And at
> that point, you can use the original "are we creating and !cmdmode
> says we are not?  That's contradiction" logic without making it more
> bizarre with this patch, no?

Nothing about this patch is needed for the rest of the series. I just
tried rebasing it out now and all tests pass & everything works as
expected.

The reason I'm submitting it is because while this works *now* and
there's no cases I can see currently where cmdmode is 'l' after the
current `((create_tag_object || force) && (cmdmode != 0))`, during a
lengthy debugging session when I was hacking on a subsequent patch in
this series it took me a long time to track down a segfault later in
the file because surely it was impossible that I was in cmdmode = 'l'
with only "git tag -a".

Partly that was late night hacking session blindness after having read
the !argc and assuming that the -a would be counted towards argc.

But I thought it was very a very bizarre pattern to set us to cmdmode
= 'l' when we're not in that mode at all just to, as can be seen in
the diff, get around a slightly more verbose one-time if-check.

So I think it's worth it to include this for less confusion in any
subsequent patches to tag.c.

  reply index

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-18 10:32 [PATCH 0/8] Various changes to the "tag" command Ævar Arnfjörð Bjarmason
2017-03-18 10:32 ` [PATCH 1/8] tag: Remove a TODO item from the test suite Ævar Arnfjörð Bjarmason
2017-03-18 18:14   ` Junio C Hamano
2017-03-18 18:42     ` [PATCH 0/2] doc/SubmittingPatches: A couple of minor improvements Ævar Arnfjörð Bjarmason
2017-03-18 18:42     ` [PATCH 1/2] doc/SubmittingPatches: clarify the casing convention for "area: change..." Ævar Arnfjörð Bjarmason
2017-03-18 19:04       ` Junio C Hamano
2017-03-18 19:16         ` Ævar Arnfjörð Bjarmason
2017-03-18 20:07           ` Junio C Hamano
2017-03-18 18:42     ` [PATCH 2/2] doc/SubmittingPatches: show how to get a CLI commit summary Ævar Arnfjörð Bjarmason
2017-03-18 19:07       ` Junio C Hamano
2017-03-19  0:48   ` [PATCH 1/8] tag: Remove a TODO item from the test suite Jakub Narębski
2017-03-19  6:43     ` Ævar Arnfjörð Bjarmason
2017-03-18 10:32 ` [PATCH 2/8] tag: Refactor the options handling code to be less bizarro Ævar Arnfjörð Bjarmason
2017-03-18 18:35   ` Junio C Hamano
2017-03-18 19:13     ` Ævar Arnfjörð Bjarmason [this message]
2017-03-18 19:27       ` Junio C Hamano
2017-03-18 20:00         ` Ævar Arnfjörð Bjarmason
2017-03-18 10:32 ` [PATCH 3/8] tag: Change misleading --list <pattern> documentation Ævar Arnfjörð Bjarmason
2017-03-18 18:43   ` Junio C Hamano
2017-03-18 19:49     ` Ævar Arnfjörð Bjarmason
2017-03-20  3:44     ` Jeff King
2017-03-20 15:55       ` Junio C Hamano
2017-03-20 17:07         ` Junio C Hamano
2017-03-20 16:09       ` Ævar Arnfjörð Bjarmason
2017-03-20 16:11         ` Jeff King
2017-03-18 10:32 ` [PATCH 4/8] tag: Implicitly supply --list given another list-like option Ævar Arnfjörð Bjarmason
2017-03-20  3:55   ` Jeff King
2017-03-20  9:16     ` Ævar Arnfjörð Bjarmason
2017-03-18 10:32 ` [PATCH 5/8] tag: Implicitly supply --list given the -n option Ævar Arnfjörð Bjarmason
2017-03-20  4:02   ` Jeff King
2017-03-18 10:32 ` [PATCH 6/8] ref-filter: Add --no-contains option to tag/branch/for-each-ref Ævar Arnfjörð Bjarmason
2017-03-20  4:25   ` Jeff King
2017-03-20  9:32     ` Ævar Arnfjörð Bjarmason
2017-03-20 19:52       ` Jeff King
2017-03-20 20:04         ` Ævar Arnfjörð Bjarmason
2017-03-18 10:32 ` [PATCH 8/8] tag: Change --point-at to default to HEAD Ævar Arnfjörð Bjarmason
2017-03-18 18:54   ` Junio C Hamano
2017-03-18 19:52     ` Ævar Arnfjörð Bjarmason
2017-03-20  4:26 ` [PATCH 0/8] Various changes to the "tag" command Jeff King
2017-03-20 15:57   ` Junio C Hamano
2017-03-21 15:51 [PATCH v2 2/2] doc/SubmittingPatches: show how to get a CLI commit summary SZEDER Gábor
2017-03-21 17:58 ` Junio C Hamano
2017-03-21 18:47   ` Ævar Arnfjörð Bjarmason
2017-03-21 20:01   ` SZEDER Gábor
2017-03-21 20:13     ` Junio C Hamano

Reply instructions:

You may reply publically 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='CACBZZX4Zs=00QXv5eaafQd8-n7OakcL3WeQh8XxiMo-9a+kAzQ@mail.gmail.com' \
    --to=avarab@gmail.com \
    --cc=christian.couder@gmail.com \
    --cc=git@vger.kernel.org \
    --cc=gitster@pobox.com \
    --cc=hjemli@gmail.com \
    --cc=jasampler@gmail.com \
    --cc=peff@peff.net \
    --cc=sam@rfc1149.net \
    --cc=tmgrennan@gmail.com \
    /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

git@vger.kernel.org mailing list mirror (one of many)

Archives are clonable:
	git clone --mirror https://public-inbox.org/git
	git clone --mirror http://ou63pmih66umazou.onion/git
	git clone --mirror http://czquwvybam4bgbro.onion/git
	git clone --mirror http://hjrcffqmbrq6wope.onion/git

Newsgroups are available over NNTP:
	nntp://news.public-inbox.org/inbox.comp.version-control.git
	nntp://ou63pmih66umazou.onion/inbox.comp.version-control.git
	nntp://czquwvybam4bgbro.onion/inbox.comp.version-control.git
	nntp://hjrcffqmbrq6wope.onion/inbox.comp.version-control.git
	nntp://news.gmane.org/gmane.comp.version-control.git

 note: .onion URLs require Tor: https://www.torproject.org/
       or Tor2web: https://www.tor2web.org/

AGPL code for this site: git clone https://public-inbox.org/ public-inbox