Re: [PATCH 3/7] oid_object_info(): return "enum object_type"

Junio C Hamano [off-list ref] writes:

And the issue is the same for all the other explicit comparison with
OBJ_BAD.  If we do it the other way around, i.e. leave these callers
as they are and add new negative return values to the function first,
and then convert "if negative, say error" to "if OBJ_BAD, say so,
else if we have this new type of error, say so", then the risk of
mistake becomes smaller.

But hopefully any such potential issue will be resolved by the end
of this short series, so as long as it won't be left as technical
debt, I am OK.

And after reading through the topic to the end, it turns out that
the code did not add new error return value.  So while it probably
is a good idea to make oid_object_info() to return the enum, I am
not convinced that the updates to the caller that used to check for
the negativeness is an improvement.  Rewriting the ones that used to
compare with -1 for equality to instead compare with OBJ_BAD would
be very much welcome, though.