githelp: replace suggestion of `hg record` `hg record` is deprecated in favor of `hg commit --interactive`. Differential Revision: https://phab.mercurial-scm.org/D1726

githelp: remove reference to tweakdefaults This is a Facebook-ism. Differential Revision: https://phab.mercurial-scm.org/D1725

githelp: recommend `hg import` for `git am` This referenced a third party extension. It doesn't feel appropriate to do that from a core extension. Reference `hg import` instead. Differential Revision: https://phab.mercurial-scm.org/D1724

githelp: improve help for `git add` The old code was referencing record and crecord, which are deprecated. `hg commit --interactive` is the preferred mechanism to use. In addition, there was duplicate code in this function. It has been removed. Tests have been added to cover this function. Differential Revision: https://phab.mercurial-scm.org/D1723

githelp: vendor Facebook authored extension This commit vendors the Facebook-authored "githelp" extension. This extension provides a "githelp" command that can be used to try to convert a `git` command to its Mercurial equivalent. This functionality is useful for Git users learning Mercurial. The extension was copied from the repository at revision 32ceeccb832c433b36e9af8196814b8e5a526775. The following modifications were made: * The "testedwith" value has been changed to match core's conventions. * Support for a custom footer has been removed, as it is Facebook specific. The feature is useful. But the implementation wasn't appropriate for core. * A test referencing "tweakdefaults" has been removed. * Imports changed to match Mercurial's style convention. * Double newlines in test removed. * Pager activation changed to ui.pager(). * Initial line of githelp.py changed to add description of file. The removal of the custom footer code was the only significant source change. The rest were mostly cosmetic. There are still some Facebook-isms in the extension. I'll address these as follow-ups. .. feature:: githelp extension The "githelp" extension provides the ``hg githelp`` command. This command attempts to convert a ``git`` command to its Mercurial equivalent. The extension can be useful to Git users new to Mercurial. Differential Revision: https://phab.mercurial-scm.org/D1722

merge: use public interface ms.localctx instead of ms._local

bookmarks: display the obsfate of hidden revision we create a bookmark on Display the same message we added recently to the filtered error message create a bookmark on an hidden revision. Differential Revision: https://phab.mercurial-scm.org/D1870

update: display the obsfate of hidden revision we update to Display the same message we added recently to the filtered error message when updating to a hidden obsolete changeset. Differential Revision: https://phab.mercurial-scm.org/D1869

evolution: make reporting of new unstable changesets optional This makes it possible to turn off the reporting of unstable changesets (e.g. "1 new orphan changesets"), just in case it's too slow for some users. Anyone who's been using the evolve extension has already been accepting the cost of the reporting, so this is just for the few users who have turned on obsmarkers but not been using the evolve extension (as I believe Facebook has). Differential Revision: https://phab.mercurial-scm.org/D1868

evolution: report new unstable changesets This adds a transaction summary callback that reports the number of new orphan, content-divergent and phase-divergent changesets. The code for reporting it is based on the code from the evolve extension, but simplified a bit. It simply counts the numbers for each kind of instability before and after the transaction. That's obviously not very efficient, but it's easy to reason about, so I'm doing this as a first step that can make us quite confident about the test case changes. We can optimize it later and make sure that the tests are not affected. The code has been used in the evolve extension for a long time and has apparently been sufficiently fast, so it doesn't seem like a pressing issue. Unlike the evolve extension's version of this report, this version applies to all commands (or all transactions run as part of any command, to be exact). Differential Revision: https://phab.mercurial-scm.org/D1867