Subject: Re: [PATCH v2 2/6] usage.c: add a non-fatal bug() function to go with BUG()

From: Junio C Hamano <[email-masked]>
Date: Wed, 01 Jun 2022 11:50:04 -0700

Ævar Arnfjörð Bjarmason  <[email-masked]> writes:

> Unlike the code this replaces we'll log to trace2 with this new bug()
> function (as with other usage.c functions, including BUG()),

I do not terribly mind repeated fprintf(stderr, ...) or error() in a
loop, but this aspect of the change is probably among the two things
that make the series shine (the other obviously being bug_if() which
allows us to lose the "did we see any bug?" counter).

> Any caller to bug() can follow up such calls with BUG_if_bug(),
> which will BUG() out (i.e. abort()) if there were any preceding calls
> to bug(), callers can also decide not to call BUG_if_bug() and leave
> the resulting BUG() invocation until exit() time. There are currently
> no bug() API users that don't call BUG_if_bug() themselves after a
> for-loop, but allowing for not calling BUG_if_bug() keeps the API
> flexible. As the tests and documentation here show we'll catch missing
> BUG_if_bug() invocations in our exit() wrapper.

OK.

> I'd previously proposed this as part of another series[1], in that
> use-case we ended thinking a BUG() would be better (and eventually
> 96e41f58fe1 (fsck: report invalid object type-path combinations,
> 2021-10-01) ended up with neither). Here though we'll end up
> converting various existing code that was already doing what we're
> doing better with this new API.

I think the last paragraph is an after-three-dash material.