git config tests for "'git config ignores pairs ..." (was Re: [PATCH v2 3/6] t1300: don't create unused files)

[Andrei Rybak <rybak.a.v@gmail.com>]

On 06/04/2023 23:30, Andrei Rybak wrote:
> On 06/04/2023 10:38, Ævar Arnfjörð Bjarmason wrote:
>>
>> Ditto my comment on 1/6, shouldn't we instead be doing e.g.:
>>
>>     diff --git a/t/t1300-config.sh b/t/t1300-config.sh
>>     index 2575279ab84..df2070c2f09 100755
>>     --- a/t/t1300-config.sh
>>     +++ b/t/t1300-config.sh
>>     @@ -1575,7 +1575,8 @@ test_expect_success 'barf on syntax error' '
>>          [section]
>>          key garbage
>>          EOF
>>     -    test_must_fail git config --get section.key >actual 2>error &&
>>     +    test_must_fail git config --get section.key >out 2>error &&
>>     +    test_must_be_empty out &&
>>          test_i18ngrep " line 3 " error
>>      '
>>
>> I.e. before this we had no coverage on the error being the only output,
>> but seemingly by mistake. Let's just assert that, rather than dropping
>> the redirection entirely, no?
> 
> Here, failing invocations of "git config" are tested, and an argument,
> as Junio C Hamano outlined in 
> https://lore.kernel.org/git/xmqqsfe8s56p.fsf@gitster.g/
> for output of failing "git mktree", could be applied here.
> 
> Thinking about it more, such assertions enforcing empty standard output for
> these commands might be helpful if some tools and/or scripts rely on empty
> standard output instead of checking the exit code.  Hyrum's Law applies 
> here,
> I guess.

There are some tests in t/t1300-config.sh that do check that standard output
or standard error is empty.  And I think I stumbled some other broken tests,
while checking those.

Test 'git config ignores pairs without count' checks that standard error
(2>error) is empty.  Just below it, there seems to be a copy-paste error:
there are two tests titled 'git config ignores pairs with zero count'.
First one doesn't check any output, but the second checks standard output,
while calling the file "error" (>error). Test 'git config ignores pairs
with empty count' checks >error as well.

They were all introduced in d8d77153ea (config: allow specifying config entries
via envvar pairs, 2021-01-12) by Patrick Steinhardt.  Patrick, what do you think?