topic: look for topic heads only when necessary Before this patch, if repo.branchheads() were asked to return heads of a branch and if there is any active topic, it would append that topic name to branch name and search heads for it and return wrong results. Because of this behavior we get wrong results for "hg heads" command because, this command make a list of heads of each branch in branchmap. So if wdir parent has an active topic, it would search for "branch:topic" instead of "branch" for each branch. Now we append topic only when branch is not passed to the function. Changes in test-topic.t file reflect the fixed behavior. Changes in test-topic-stack-data.t are obvious but not correct for `hg sum` output, which is because that's what the expected behavior acc. to the current logic in `hg sum` as it looks for the heads of branch of wdir parent and calculate new commits like this: new = ancestor(all branch heads) - ancestor(current parent) So, it doesn't really care if wdir parent has a topic which is why we are getting wrong result for "update:" in `hg sum`. You might be wondering why it was returning the correct output before, but I digged into it and can tell you that it's just a false combination of current cset and code bits which gave the correct results. If we want to correctly fix the issue we probably need to wrap `hg sum` command.