rewriteutil: allow rewriting merge commits (issue4561) This patch simply allows rewriteutil.rewrite() to work with commits with multiple parents (i.e. merges). That function is used in such commands as fold, metaedit, touch, rewind. The issue 4561 is marked as easy, the limitation is called unnecessary, no tests fail after this change. What can go wrong.

tests: show what happens when trying to hg touch a merge commit

evolve: further clarify that update is performed only when requested Text further modified by Pierre-Yves David and Anton Shestakov.

touch: let's not use util.acceptintervention() as it's not required

branching: merge with stable

evolve: use right value for branch name when finding branch heads subbranch already formatted as "branchname:topicname", again appending it with ":topicname" doesn't not make sense. It's a little bit surprising that no tests fails though.

evolve: fix confusion in branch heads checking logic when topic in play To provide some context, when topics are in play the branchmap cache we store contains the branch info of a rev as "branch:topic" format IIUC. Assuming that is right, now in present code we don't actually cover this part that "when looking for branch heads where we also have active topic we should look for branch='branch_name:topic' instead". And we get wrong branch heads as a result. This patch make sure that we pass right candidate to find branch heads using branchmap.branchheads() by overriding the localrepo.branchheads() Changes in test file reflect the fixed behavior.