Replaced fixed window size for walkchangerevs with an increasing one. Window sizes starts at 8 (for good interactiveness) and doubles with each window until it is 512, which seems to be the maximum efficient value.

#!/bin/sh

mkdir a
cd a
hg init
echo foo > b
hg add b
hg ci -m "b" -d "0 0"

chmod -w .hg

cd ..

hg clone a b

chmod +w a/.hg # let test clean up

cd b
hg verify