revset: speed up '_matchfiles' File matching is done by applying the matcher to all elements in the 'file' field of all changesets in the repository. This requires to read/parse all changesets in the repository and do a lot of matching. However about 1/3 of the time of the function is used to create 'changectx' object and retrieve their 'file' field. This is far too much overhead so we are skipping the changectx layer and directly access the data from the changelog. This provide use significant speed up: repository: mozilla central 252524 revisions command: hg perfrevset '_matchfiles("p:browser")' Before: 15.899687s After: 10.011705s Slowdown is even more significant if you have a lot of namespace that slowdown lookup. The time is now spent with this approximate repartition: Matcher: 20% regexp matching: 10% changelog.read: 80% reading revision: 60% checking hash: 15% decompression: 15% reading chunk: 30% changelog parsing: 20% decoding to local: 10% The next easy win is probably to have more of the changelog stack implemented using the CPython api.

mergestate: handle additional record types specially This works around a bug in older Mercurial versions' handling of the v2 merge state. We also add a bunch of tests that make sure that (1) we correctly abort when the merge state has an unsupported record type (2) aborting the merge, rebase or histedit continues to work and clears out the merge state.

test-resolve.t: remove completely unnecessary line I have no idea what I was thinking when I wrote this.

resolve: fix incorrect merge The merge from stable into default was semantically incomplete -- a couple of changes in preceding code had to be rewritten here. This code only triggers for change/delete conflicts, so we can't test it yet. We will soon be able to do it, though.

fileset: add missing() predicate (issue4925) Help of status cmd defines status file of 'missing', what is called in fileset 'deleted'. To stay consistent this patch introduces missing() predicate which in fact is alias to 'deleted'.

webutil: make _siblings into an object with __iter__ and __len__ _siblings is a helper that is used for displaying changeset parents and children in hgweb. Before, when it was a simple generator, it couldn't tell its length without being consumed, and that required a special case when preparing data for changeset template (see 9e1f4c65f5f5). Let's make it into a class (similar to templatekw._hybrid) that allows len(...) without side-effects.

mergestate: move binary format documentation into _readrecordsv2 This is too low-level to be the top-level documentation for mergestate. We're restricting the top-level documentation to only be about what consumers of the mergestate and anyone extending it need to care about.