Clean up some merge logic - rename mode to branch_merge - use explicit update mode - use negative mtime for updates that set mtime - expand some cryptic variable names - elaborate merge dirstate comments - remove redundant manifest lookup for non-merge case - remove impossible merge case - fix up test cases

#!/bin/sh

mkdir a
cd a
hg init
echo foo > t1
hg add t1
hg commit -m "1" -d "0 0"

cd ..
hg clone a b

cd a
echo foo > t2
hg add t2
hg commit -m "2" -d "0 0"

cd ../b
echo foo > t3
hg add t3
hg commit -m "3" -d "0 0"

hg push ../a
hg pull ../a
hg push ../a
hg up -m
hg commit -m "4" -d "0 0"
hg push ../a