dirstate walking optimizations The repo walking code introduces a number of calls to dirstate.map.copy(), significantly slowing down the walk on large trees. When a list of files is passed to the walking code, we should only look at map entries relevant to the file list passed in. dirstate.filterfiles() is added to return a subset of the dirstate map. The subset includes in files passed in, and if one of the files requested is actually a directory, it includes any files inside that directory tree. This brings the time for hg diff Makefile down from 1.7s to .3s on a linux kernel repo. Also, the diff command was unconditionally calling makewalk, leading to an extra pass through repo.changes. This patch avoids the call to makewalk when commands.diff isn't given a list of patterns, cutting the time for hg diff (with no args) in half. Index: mine/mercurial/hg.py ===================================================================

+ hg init
+ hg add t1
+ hg commit -m 1 -d 0 0
+ hg clone a b
+ hg add t2
+ hg commit -m 2 -d 0 0
+ hg add t3
+ hg commit -m 3 -d 0 0
+ hg push ../a
pushing to ../a
searching for changes
abort: unsynced remote changes!
(did you forget to sync? use push -f to force)
+ hg pull ../a
pulling from ../a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
(run 'hg update' to get a working copy)
+ hg push ../a
pushing to ../a
searching for changes
abort: push creates new remote branches!
(did you forget to merge? use push -f to force)
+ hg up -m
+ hg commit -m 4 -d 0 0
+ hg push ../a
pushing to ../a
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 2 files