Fix cold cache diff performance cold cache diff performance has regressed in two ways. localrepo.changes has optimizations for diffing against the working dir parent that expect node1 to be None. commands.revpair() usage means that commands.dodiff() never sends node1 == None. This is fixed in localrepo.changes by checking against the dirstate parents. In the non-dirstate parents case, localrepo.changes does a loop comparing files without first sorting the file names, leading to random access across the disk.

#!/bin/sh

set -e

mkdir test
cd test
echo foo>foo
hg init
hg addremove
hg commit -m "1"
hg verify

hg clone . ../branch
cd ../branch
hg co
echo bar>>foo
hg commit -m "2"

cd ../test
hg pull ../branch
hg verify
hg co
cat foo
hg manifest