Subject: Re: [PATCH 3/5] diff: acknowledge --submodule=short command-line option

From: Jens Lehmann <[email-masked]>
Date: Sun, 07 Oct 2012 21:49:28 +0200

Am 07.10.2012 17:22, schrieb Ramkumar Ramachandra:
> Jens Lehmann wrote:
>> Am 02.10.2012 18:51, schrieb Ramkumar Ramachandra:
>>> Currently, the diff code does not differentiate between an explicit
>>> '--submodule=short' being passed, and no submodule option being passed
>>> on the command line.  Making this differentiation will be important
>>> when the command-line option can be used to override a
>>> "diff.submoduleFormat" configuration variable introduced in the next
>>> patch.
>>
>> Wouldn't it be sufficient here to simply reset the log flag by using
>> "DIFF_OPT_CLR(options, SUBMODULE_LOG)"? This would avoid having to
>> use the last bit of the diffopt flags. And if I read the code correctly,
>> diff_opt_parse() is called by setup_revisions() which is called after
>> git_config(), so that should be safe. (And "textconv" uses the same
>> approach)
> 
> How is it sufficient?  In git_diff_ui_config(), I set
> submodule_format_cfg, which has nothing to do with SUBMODULE_LOG.  In
> builtin_diff(), I'll have to check SUBMODULE_LOG and
> submodule_format_cfg.  The tricky bit is that I should check
> submodule_format_cfg if and only if "--submodule=short" was NOT passed
> on the command line-  now, that's not the same thing is checking if
> SUBMODULE_LOG is unset, because SUBMODULE_LOG is unset (or cleared) if
> no argument was passed or if "--submodule=short" is passed.
> Therefore, I need a SUBMODULE_SHORT to differentiate between the two
> cases.
> 
> What am I missing?

I forgot to mention that testing submodule_format_cfg would have to
happen in cmd_diff() (between reading the config and parsing the
command line options) instead of builtin_diff(). Something like this
should do the trick (untested):

diff --git a/builtin/diff.c b/builtin/diff.c
index 9650be2..180bf44 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -297,6 +297,9 @@ int cmd_diff(int argc, const char **argv, const char *prefix
        DIFF_OPT_SET(&rev.diffopt, ALLOW_EXTERNAL);
        DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);

+       if (submodule_format_cfg && !strcmp(submodule_format_cfg, "log"))
+               DIFF_OPT_SET(options, SUBMODULE_LOG);
+
        if (nongit)
                die(_("Not a git repository"));
        argc = setup_revisions(argc, argv, &rev, NULL);