context: optimize linkrev adjustment in blockancestors() (issue5538) stable
authorDenis Laxalde <denis.laxalde@logilab.fr>
Mon, 24 Apr 2017 18:33:23 +0200
branchstable
changeset 32069 a457da5296a5
parent 32068 51fdedd29b0a
child 32070 a298f5c61b34
context: optimize linkrev adjustment in blockancestors() (issue5538) We set parent._descendantrev = child.rev() when walking parents in blockancestors() so that, when linkrev adjustment is perform for these, it starts from a close descendant instead of possibly topmost introrev. (See `self._adjustlinkrev(self._descendantrev)` in filectx._changeid().) This is similar to changeset c82d88dfaf59, which added a "f._changeid" instruction in annotate() for the same purpose. However, here, we set _descendantrev explicitly instead of relying on the '_changeid' cached property being accessed (with effect to set _changeid attribute) so that, in _parentfilectx() (called from parents()), we go through `if '_changeid' in vars(self) [...]` branch in which instruction `fctx._descendantrev = self.rev()` finally appears and does what we want. With this, we can roughly get a 3x speedup (including in example of issue5538 from mozilla-central repository) on usage of followlines revset (and equivalent hgweb request).
mercurial/context.py
--- a/mercurial/context.py	Mon Apr 24 17:13:24 2017 +0200
+++ b/mercurial/context.py	Mon Apr 24 18:33:23 2017 +0200
@@ -1214,6 +1214,10 @@
                 # introduced in this revision; no need to go futher in this
                 # branch.
                 continue
+            # Set _descendantrev with 'c' (a known descendant) so that, when
+            # _adjustlinkrev is called for 'p', it receives this descendant
+            # (as srcrev) instead possibly topmost introrev.
+            p._descendantrev = c.rev()
             visit[p.linkrev(), p.filenode()] = p, linerange1
         if inrange:
             yield c, linerange2