Re: [PATCH v2] revision: add `--ignore-missing-links` user option

> > +# We create 5 commits and move them to the alt directory and
> > +# create 5 more commits which will stay in the main odb.
> > +test_expect_success 'create repository and alternate directory' '
> > +     git init main &&
>
> We don't necessarily have to initialize a repository, as the test suite
> already does so for us. So we may want to write this instead as:
>
>     test_commit_bulk 5 &&
>     git clone --reference=. --shared . alt &&
>     test_commit_bulk -C alt --start=6 5
>

> > +# when the alternate odb is provided, all commits are listed along with the boundary
> > +# commit.
> > +test_expect_success 'rev-list passes with alternate object directory' '
> > +     GIT_ALTERNATE_OBJECT_DIRECTORIES=$PWD/alt git -C main rev-list HEAD >actual &&
> > +     test_stdout_line_count = 10 cat actual &&
> > +     grep $BOUNDARY_COMMIT actual
> > +'
>
> Here, I think we'd want to make sure that we have not just 10 lines of
> output, but that they are the 10 that we expect, like so:
>
>     git -C alt rev-list --all --objects --no-object-names >actual.raw &&
>     {
>       git rev-list --all --objects --no-object-names &&
>       git -C alt rev-list --all --objects --no-object-names --not \
>         --alternate-refs
>     } >expect.raw &&
>     sort actual.raw >actual &&
>     sort expect.raw >expect &&
>     test_cmp expect actual
>
> When reviewing this and tweaking some of the tests locally, I found it
> useful to have some convenience functions like "hide_alternates" and
> "show_alternates" to control whether or not "alt" could see its
> alternate or not.
>
> From my review locally, the resulting changes (which can be applied
> directly on top of your patch here look like):
>