annotate: always adjust linkrev before walking down to parents (issue4623) This should avoid the bad performance in the following scenario. Before this patch, on "hg annotate -r10000", p.rev() would walk changelog from 10000 to 3 because _descendantrev was 10000. With this patch, it walks from 5 to 3. 1 -- 2 -- 4 -- 5 -- ... -- 10000 \ 'p' 'f' - 3 (grafted 3 to 4) 'p' repo: https://hg.mozilla.org/releases/mozilla-beta/#4f80fecda802 command: hg annotate -r b0a57152fd14 browser/app/profile/firefox.js before: 83.120 secs after: 3.820 secs This patch involves extra calls of narrow _adjustlinkrev(), but the cost of them seems relatively small compared to wide _adjustlinkrev() calls eliminated by this patch. repo: http://selenic.com/repo/hg/#8015a3cf1380 command: hg annotate mercurial/commands.py before: 7.380 secs after: 7.320 secs repo: https://hg.mozilla.org/mozilla-central/#f214df6ac75f command: hg annotate layout/generic/nsTextFrame.cpp before: 5.070 secs after: 5.050 secs repo: https://hg.mozilla.org/releases/mozilla-beta/#4f80fecda802 command: hg annotate -r 4954faa47dd0 gfx/thebes/gfxWindowsPlatform.cpp before: 1.600 secs after: 1.620 secs

--- a/mercurial/context.py	Sun Apr 26 15:13:13 2015 -0400
+++ b/mercurial/context.py	Sat Apr 25 15:38:06 2015 +0900
@@ -887,6 +887,11 @@
         getlog = util.lrucachefunc(lambda x: self._repo.file(x))
 
         def parents(f):
+            # Cut _descendantrev here to mitigate the penalty of lazy linkrev
+            # adjustment. Otherwise, p._adjustlinkrev() would walk changelog
+            # from the topmost introrev (= srcrev) down to p.linkrev() if it
+            # isn't an ancestor of the srcrev.
+            f._changeid
             pl = f.parents()
 
             # Don't return renamed parents if we aren't following.