test-copies: add a test updating file content while merging a pure overwrite As the current test misbehavior show, this confuse various part of the code: - the committed file is different depending of the commit source, - the upgrade code compute the wrong information on this changeset. This will be fixed in upcoming patches. Differential Revision: https://phab.mercurial-scm.org/D10087

mergestate: don't pop stateextras when there are no conflicts on filemerge Even if `filemerge.filemerge()` didn't result in conflicts, we should not remove stateextras for a file since we now use that for more things than just merge time information. We use stateextras to store information which is required to be used by commit. I tracked this down while finding why a patch of mine which adds more commit related information does not work as expected and looses the extras in mergestate. Differential Revision: https://phab.mercurial-scm.org/D10148

node: introduce nodeconstants class In preparing for moving from SHA1 hashes to a modern hash function, place nullid and other constant magic vules in a class. Provide the active set of constants in the repository and push it down. Provide nullid directly in strategic places like the repository as it is accessed very often. This changeset introduces the API change, but not the mechanical replacement of the node.py attributes itself. Differential Revision: https://phab.mercurial-scm.org/D9750

revlog: guarantee that p1 != null if a non-null parent exists This change does not affect the hashing (which already did this transformation), but can change the log output in the rare case where this behavior was observed in repositories. The change can simplify iteration code where regular changesets and merges are distinct branches. Differential Revision: https://phab.mercurial-scm.org/D10150

push: allow to specify multiple destinations I end up needing that on a regular basis and it turn out to be very simple to implement. See documentation and test for details. Differential Revision: https://phab.mercurial-scm.org/D10161

push: indent the some part of the command That code will be put in a loop in the next changeset, pre-indenting make the next change clearer. Differential Revision: https://phab.mercurial-scm.org/D10160