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

> On Fri, Sep 06, 2019 at 12:48:05PM -0400, Derrick Stolee wrote:
> 
>>> diff --git a/revision.h b/revision.h
>>> index 4134dc6029..5c0b831b37 100644
>>> --- a/revision.h
>>> +++ b/revision.h
>>> @@ -33,7 +33,7 @@
>>>  #define ALL_REV_FLAGS	(((1u<<11)-1) | NOT_USER_GIVEN | TRACK_LINEAR)
>>>  
>>>  #define TOPO_WALK_EXPLORED	(1u<<27)
>>> -#define TOPO_WALK_INDEGREE	(1u<<28)
>>> +#define TOPO_WALK_INDEGREE	(1u<<24)
>>
>> As an aside, these flag bit modifications look fine, but would need to
>> be explained. I'm guessing that since you are adding a bit of data
>> to struct object you want to avoid increasing the struct size across
>> a 32-bit boundary. Are we sure that bit 24 is not used anywhere else?
>> (My search for "1u<<24" found nothing, and "1 << 24" found a bit in
>> the cache-entry flags, so this seems safe.)
> 
> Yeah, I'd definitely break this up into several commits with explanation
> (though see an alternate I posted that just uses the parsed flag without
> any new bits).
> 
> Bit 24 isn't used according to the table in objects.h, which is
> _supposed_ to be the source of truth, though of course there's no
> compiler-level checking. (One aside: is there a reason TOPO_WALK_* isn't
> part of ALL_REV_FLAGS?).