Re: [RFC PATCH 1/1] commit-graph.c: die on un-parseable commits

> I don't think parse_commit_no_graph() returning 0 assures us that
> get_commit_tree() and friends will return non-NULL.
>
> This is similar to the case discussed recently where a failed parse of a
> tag may leave "tag->tagged == NULL" even though "tag->obj.parsed" is
> set.
>
> Here an earlier parsing error could cause (*list)->object.parsed to be
> true, but with (*list)->maybe_tree still NULL. Our call to
> parse_commit_no_graph() here would silently return "yep, already tried
> to parse this", and then we'd still segfault.
> ...
> And I think there's literally no way for this function to tell the
> difference between "no parent" and "there was an earlier error, but we
> set the parsed flag anyway and the parent flag is invalid".
>
> I think that argues against Junio's response in: