On Thu, Sep 19, 2013 at 09:58:23PM -0700, Junio C Hamano wrote: > Jeff King <p...@peff.net> writes: > > > One question, though. With your patch, if I do "tag1..tag2", I get both > > the tags and the peeled commits in the pending object list. Whereas with > > "^tag1 tag2", we put only the tags into the list, and we expect the > > traversal machinery to peel them later. I cannot off-hand think of a > > reason this difference should be a problem, but I am wondering if there > > is some code path that does not traverse, but just looks at pending > > objects, that might care. > > Did I really do that? > > I thought that the original was pushing peeled tag1^0 and tag2^0 > (and nothing else) for "tag1..tag2", and the intent of the patch was > to see if "a" (which is "tag1^0" in this case) has the same object > name as the object originally given on the side of the dots > (i.e. "tag1"). If they differ, that means "a" is the peeled object, > and instead use the original "tag1" for "a_obj" that is pushed into > the pending (and if they are the same, "a_obj" is just "&a->object", > the object itself). The same for "b", "tag2" and "b_obj". So at > least I didn't mean to push four objects into the pending list > before prepare_revision_walk() kicks in. > > Perhaps I missed something?
Hrm, no, it is me misreading the diff. My original question was going to be: why bother peeling at all if we are just going to push the outer objects, anyway? And after staring at it, I somehow convinced myself that the answer was that you were pushing both. But that is not the case. Sorry for the noise. The other reason I considered is that we want to make sure they do peel to commits. I do not think that is technically required for "A..B", which can operate on non-commits. But it is for "A...B", and I do not see any advantage in loosening "A..B" for the non-commit case. It would just complicate the code. > Now, when prepare_revision_walk() picks up objects from the pending > list, they are fed to handle_commit(), and these two tags will be > peeled and their commits are returned to be queued in revs->commits > linked list, while the tags themselves are sent to the pending list > to be emitted in "--objects" output. But that should be the same > between "tag1..tag2" and "^tag1 tag2". Yes, I was specifically concerned about sites that did not call prepare_revision_walk(), but since the state is the same for both cases, it's a non-issue. > it"). But I do not think any code just tries to grab an object > using a random object name outside the revision traversal and decide > to do things that results in semantically different behaviour if the > resulting object has (or has not) already been parsed. Yeah, I think any code relying on that would be insane, from a modularity perspective. The caching of parsed object state is an optimization, and callers have no business making assumptions about it. Otherwise they are fragile with respect to a previous traversal being added in the same in-memory process. So I think your patch is doing the right thing, and my concern was just from mis-reading. Again, sorry for the confusion. -Peff -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
