stack: reusing the index number in base when applicable This clarify the branching when it is easy to track back the branching point. This does not takes the evolution graph into account yet.

stack: extra argument validation logic outside of showstack It seems sensible keep the 'showstack' function purely about actually displaying and existing stack.

summary: properly label the topic name in summary This should be labelled 'topic.active' so that color can pick it up properly.

topic: list the branches this topic belong to when verbose Using the verbose listing a bit more, this seems to be useful information.

topic: properly justify the verbose data when listing topic We align all data to the widest topic.

ngtip: rely on topicmap for 'ngtip' ngtip is an old function that predates the introduction of a more proper topic aware 'topicmap'. We replace the old code with a call to the new one. This change set function return type and have minor effect in a couple of place.

topic: list the number of 'behind' changeset when --verbose is used Displaying more information in the topic list is useful, we continue with the number of 'behind' changesets. This 'behind' count the number of new changesets on the default rebase destination. This will highlight topics that need rebasing.

destination: honor the sourceset argument of _destmerge Mercurial gained a "sourceset" argument to compute the merge destination of any changeset (the one in the 'sourceset'). This now works for the version in topic too. The support is quite basic (because we pick only one changeset from the sourceset) but that's a start.

destmerge: improve topic head computation and handling This rework get use two benefits: - heads are now computed on a "stabilized" state, - heads above the 'source' are now properly cleaned up,

evolve: extract the code copied from evolve in a submodule This will allow us to use that code in other module.