Add searching for named branches named branching is when you identify a head by a tag on an earlier revision. This patch adds repo.branchlookup for searching through the tree to find branch tags for heads. hg update -b tag is added to checkout based on branch tags hg heads -b is added to print the tag associated with each head

#!/bin/sh

hg init
echo a > a
hg add a
hg commit -m "1" -d "0 0"
hg status
cp a b
hg copy a b
hg status
hg --debug commit -m "2" -d "0 0"
hg history
hg log a
md5sum .hg/data/b.d
hg cat b > bsum
md5sum bsum
hg cat a > asum
md5sum asum
hg verify