context: default to using branch from dirstate only in workingctx Same reasoning as previous commits: only the workingctx should know about the dirstate. committablectx now seems free of dirstate references. Differential Revision: https://phab.mercurial-scm.org/D6374

context: let caller pass in branch to committablectx.__init__() committablectx.__init__() currently looks up the branch from the dirstate unless it's passed in the extras. memctx.__init__() has a branch argument, but since committablectx.__init__() doesn't accept it, it lets that constructor look up the branch from the dirstate before it overwrites it, which seems awkward. Differential Revision: https://phab.mercurial-scm.org/D6366

context: move contents of committablectx.markcommitted() to workingctx Same reasoning as previous commits: this function updates the dirstate. By not updating the dirstate here, we also fix the close-head test. Differential Revision: https://phab.mercurial-scm.org/D6365

tests: demonstrate that close-head command updates working copy The help text for the command says "...it doesn't change the working directory", so I don't think this is intentional. Differential Revision: https://phab.mercurial-scm.org/D6364

context: move walk() and match() overrides from committablectx to workingctx Same reasoning as previous commit: these functions update the dirstate. Differential Revision: https://phab.mercurial-scm.org/D6363

context: move flags overrides from committablectx to workingctx These read from the dirstate, so they shouldn't be used in other subclasses. Differential Revision: https://phab.mercurial-scm.org/D6362