Re: [PATCH v4 4/6] rev-list: handle missing tree objects properly

[Jonathan Tan <jonathantanmy@google.com>]

> > > @@ -373,6 +375,7 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
> > >       init_revisions(&revs, prefix);
> > >       revs.abbrev = DEFAULT_ABBREV;
> > >       revs.commit_format = CMIT_FMT_UNSPECIFIED;
> > > +     revs.do_not_die_on_missing_tree = 1;
> >
> > Is this correct? I would have expected this to be set only if --missing
> > was set.
> If --missing is not set, then we want to fetch missing objects
> automatically, and then die if we fail to do that, which is what
> happens for blobs.

This is true, and should already be handled. Pay attention to when
fetch_if_missing is set in builtin/rev-list.c.

do_not_die_on_missing_tree should probably be set to 1 whenever
fetch_if_missing is set to 0, I think.

(I acknowledge that the usage of this global variable is confusing, but
I couldn't think of a better way to implement this when I did. Perhaps
when the object store refactoring is done, this can be a store-specific
setting instead of a global variable.)

> So we don't want to die in list-objects.c. If we
> fail to fetch, then we will die on line 213 in rev-list.c.

Why don't we want to die in list-objects.c? When --missing=error is
passed, fetch_if_missing retains its default value of 1, so
parse_tree_gently() will attempt to fetch it - and if it fails, I think
it's appropriate to die in list-objects.c (and this should be the
current behavior). On other values, e.g. --missing=allow-any, there is
no autofetch (since fetch_if_missing is 0), so it is correct not to die
in list-objects.c.

> > As for --missing=allow-promisor, I don't see them being tested anywhere
> > :-( so feel free to make a suggestion. I would put them in t6112 for
> > easy comparison with the other --missing tests.
> Kept my allow-promisor test in t0410 since it requires partial clone
> to be turned on in the config, and because it is pretty similar to
> --exclude-promisor-objects.

OK, sounds good to me.