Re: [PATCH] [GSOC] cat-file: fix --batch report changed-type bug

[ZheNing Hu <adlternative@gmail.com>]

Jeff King <peff@peff.net> 于2021年5月31日周一 下午10:44写道：
>
> > > > +test_expect_success 'cat-file --batch="batman" with --batch-all-objects will work' '
> > > > +     git -C all-two cat-file --batch-all-objects --batch="%(objectname)" | wc -l >expect &&
> > > > +     git -C all-two cat-file --batch-all-objects --batch="batman" | wc -l >actual &&
> > > > +     test_cmp expect actual
> > > > +'
> > >
> > > Is it worth testing both of these? The %(objectname) one will fail in
> > > the same way (because we do not need to run oid_object_info() to get the
> > > oid, which we already have). I'm OK doing both for better coverage, but
> > > it may be worth mentioning either in a comment or in the commit message
> > > that we expect both to fail, and why.
> >
> > Yes, these damages need to be pointed out in the commit message.
>
> I think what confused me here is that you are using "%(objectname)" as
> the "expect" output, but it also exhibits the bug. So I'd expect this
> test to pass even before your patch (though I didn't try it).
>

Yes, %(objectname) should not be used as the output of "expect",
it is also a broken part.

> Really, the symptom of the bug is that _neither_ of those cat-file
> invocations will exit with a success code. But because they're on the
> left-hand side of a pipe, we wouldn't even notice.
>
> The simplest test is just:
>
>   git -C all-two cat-file --batch-all-objects --batch="%(objectname)" >/dev/null
>

Yes, this is enough. I even think about use something like
"!test_must_fail xxx" before... that is not necessary.

> which will currently fail. It would be nice to verify that its output is
> sensible, but I'm not sure how to easily do that (it will spew a bunch
> of binary tree data, and it cannot even be parsed reliably since we
> haven't output the sizes).
>
> -Peff

Thanks!
--
ZheNing Hu