unionrepo: sync with repository API Differential Revision: https://phab.mercurial-scm.org/D6289

match: remove unused match.__iter__ implementation (API) Differential Revision: https://phab.mercurial-scm.org/D6305

fix: allow fixer tools to return metadata in addition to the file content With this change, fixer tools can be configured to output a JSON object that will be parsed and passed to hooks that can be used to print summaries of what code was formatted or perform other post-fixing work. The motivation for this change is to allow parallel executions of a "meta-formatter" tool to report back statistics, which are then aggregated and processed after all formatting has completed. Providing an extensible mechanism inside fix.py is far simpler, and more portable, than trying to make a tool like this communicate through some other channel. Differential Revision: https://phab.mercurial-scm.org/D6167

merge with stable

phabricator: set local:commits time metadata as an int, not a string Same as arcanist does Differential Revision: https://phab.mercurial-scm.org/D6296

phabricator: use templatefilters.json in writediffproperties Instead of json.dumps, since it makes the code simpler and more readable. This would have been the better option for 8fd19a7b4ed6 but I wasn't aware of it at the time. Differential Revision: https://phab.mercurial-scm.org/D6295

commands: use byteskwargs() in verify() Otherwise Python 3 complains about the missing key. Differential Revision: https://phab.mercurial-scm.org/D6294

match: use raw strings to avoid illegal baskslash escape Python 3.8 was complaining about the invalid escape sequences. Let's use raw strings to avoid the warning and double baskslashes. Differential Revision: https://phab.mercurial-scm.org/D6293