Re: [PATCH] config: fix case sensitive subsection names on writing

From: Stefan Beller <sbeller@google.com>
Date: Jul 28, 2018, 03:52 UTC
Message-ID: <CAGZ79ka2yRv5+EaBoHx_TWdM1Qgt9F7YZiW=X35MyOehfcdQBg@mail.gmail.com>
In-Reply-To: <xmqqlg9wjhq7.fsf@gitster-ct.c.googlers.com>

On Fri, Jul 27, 2018 at 6:01 PM Junio C Hamano <gitster@pobox.com> wrote:

Show 6 quoted lines

>
> Stefan Beller <sbeller@google.com> writes:
>
> > A use reported a submodule issue regarding strange case indentation
>
> s/use/&r/;  Is this "indentation" issue?

eh case sensitivity*

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> > +     q_to_tab >testConfig_expect <<-EOF &&
> > +             # insensitive:
> > +             [V.A]
> > +             Qr = value2
> > +     EOF
>
> It is unfortunate that we hardcode the exact indentation
> in the test to make it care.  Perhaps a wrapper around test_cmp that
> is used locally in this file to first strip the leading HT from both
> sides of the comparison would make it more robust?

I think this is valuable for the second test to see where it was replaced.

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>
> > +     for key in "v.a.r" "V.A.r" "v.A.r" "V.a.r"
> > +     do
> > +             cp testConfig testConfig_actual &&
> > +             git config -f testConfig_actual v.a.r value2 &&
> > +             test_cmp testConfig_expect testConfig_actual
> > +     done
> > +'
>
> I think you meant to use "$key" when setting the variable to value2.
>
> When the test_cmp fails with "v.a.r" but later succeeds and most
> importantly succeeds with "V.a.r" (i.e. the last one), wouldn't the
> whole thing suceed?  I think the common trick people use is to end
> the last one with "|| return 1" in a loop inside test_expect_success.
>

Hah, of course this patch is not as easy.

The problem is in git_parse_source (config.c, line 755) when we call get_base_var it normalizes both styles, (and lower cases the dot style).

So in case of dot style, the strncasecmp is correct, but for the new extended style we need to strncmp.

So this is correct for extended but not any more for the former dot style.

I wonder if we want to either (a) add another CONFIG_EVENT_SECTION that indicates the difference between the two, or have a flag in 'cf' that tells us what kind of section style we have, such that we can check appropriately for the case. Or we could encode it in the 'cf->var' value to distinguish the old and new style.

Thanks, Stefan