Re: [PATCH v2 3/6] tests: use `git submodule add` and fix expected diffs

[Junio C Hamano <gitster@pobox.com>]

Glen Choo <chooglen@google.com> writes:

> E.g. we could have ignored .gitmodules during the diff like so
>
>   test_expect_success 'added submodule' '
>           git submodule add ./sm1 &&
>           gitmodules_hash1=$(git rev-parse --short $(git hash-object .gitmodules)) &&
>   -       git diff-index -p --submodule=log HEAD >actual &&
>   +       git diff-index -p --submodule=log HEAD -- :!.gitmodules >actual &&
>
> and then we wouldn't have to adjust the diff. That would be my preferred
> approach, since it keeps the irrelevant details out of the test.

Yes, it certainly does make the diff simpler to read, but the
reasoning cuts both ways.

The end-goal of the topic is to propose that updating .gitmodules is
an integral part of "adding a submodule" and to make it impossible
to just add gitlink without a command line option using "git add",
so from that point of view, readers would expect that the diff after
"adding a submodule" to have both new gitlink and also a modified
(or if this were the first submodule, added) ".gitmodules" file.