Junio C Hamano venit, vidit, dixit 10.03.2011 19:22: > Michael J Gruber <git@xxxxxxxxxxxxxxxxxxxx> writes: > >> ... >> Additionally, since parse_revision_opt (which calls handle_revision_opt) >> is called from other sites for individual args we would need to do the >> handling in the Y case (set pick when marking) right in >> handle_revision_opt, not just in setup_revisions. It's a matter of a few >> more if's and or's, but still. >> >> Taking these together, I wonder whether we shouldn't leave it as in v2. > > The primary downside of keeping cherry_pick and cherry_mark as independent > I see is what would happen to the "if (cherry_pick || cherry_mark)" when > somebody comes up with the next bright idea to use the change equivalence > computed in cherry_pick_list(). With the approach in v2, the natural way > of enhancing this would be to add another "|| cherry_xyzzy" there, and the > next bright idea would add another "|| cherry_frotz". > > My gut feeling was that it would be a more maintainable implementation to > have an internal bit that does not have to be exposed to the UI and that > tells the revision machinery that we need to compute the equivalence, and > an enum (if the three modes of using the equivalence are incompatible with > each other) or a one-bit-per-feature bitset (if the three features that > use the equivalence can be used at the same time) that tells the machinery > what to do with the equivalence information. From the UI level, the user > only asks for the feature(s) that use(s) the equivalence information, and > asking for any of them would set the internal "need equivalence" bit. > > The above is modeled after the way how revs.limited bit is used. That bit > corresponds to the "internal bit" that is flipped by many features that > can be triggered from the UI level that depends on having the history > graph before they do their work. > > Counting the number of "if (limited)" and tricky codepaths around it, and > contrasting that with the number of ways we flip the "limited = 1" bit > (which grew over time), I think you can understand where my fear of > potential future complexity against "if (cherry_pick || cherry_mark)" > comes from. I see, thanks for the background! Other callers of the revision walker have to remember that they need to set revs->limited already when they want to use any limitting flags, so revs->cherry_pick as in v3 would be no different.(*) So maybe we should have another flag revs->cherry_process which is set automatically when needed, after processing all options (same with limited), and leave cherry_pick to keep track of --cherry-pick? (*) Well, in fact they don't as long as they use the api correctly. blame and shortlog call parse_revision_opt but use setup_revisions and prepare_revision_walk afterwards. pack-objects calls handle_revision_arg after setup_revisions but prepare_revision_walk after. I was afraid of callers setting revs->something inconsistently and then jumping into the walker. So, maybe prepare_revision_walk is the most sensible place to set revs->limited and revs->cherry_process when needed as indicated by other flags (or set already), and take out their handling from the option parser? Michael -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html