extensions: import the exthelper class from evolve 980565468003 (API) This should help make extensions that wrap a lot of stuff more comprehendible. It was copied unmodified, except: - fix up the imports - rename final_xxxsetup() -> finalxxxsetup() to appease checkcode - avoid a [] default arg to wrapcommand() .. api:: Add `exthelper` class to simplify extension writing by allowing functions, commands, and configitems to be registered via annotations. The previous APIs are still available for use.

narrow: detect if narrowspec was changed in a different share With this commit, `hg share` should be usable with narrow repos. Design explained on https://www.mercurial-scm.org/wiki/NarrowSharePlan I was running into cache invalidation problems when updating the narrowspec. After spending a day trying to figure out a good solution, I resorted to just assigning repo.narrowpats and repo._narrowmatch after invalidating them. Differential Revision: https://phab.mercurial-scm.org/D5278

tests: add test for narrow+share For how narrow+share is supposed to work, see https://www.mercurial-scm.org/wiki/NarrowSharePlan. Differential Revision: https://phab.mercurial-scm.org/D5276

narrow: keep narrowspec backup in store As suggested by Yuya in review of D4099. Differential Revision: https://phab.mercurial-scm.org/D5470