topic: makes split keep the topic Refactor split to extract the preparation of the working directory in a separate function. This helps topic wrap this function to save topic before update and restore it after preparing the working directory just before the split.

topic: add tests for fold behavior with topics Clarify the fold behavior for keeping topics.

topics: pass quietempty=True to suppress useless output while changing topics This will help in suppressing the output "0 files updated, 0 file removed, ..."

topics: return early so that other if conditions don't get execute (issue5600) We were not returning after the _changetopics() call and hence the if's below it were also executed which resulted in changing of current topic. This prevent current topic to be updated even when we only affect changeset unrelated to the working copy. Not that the rebase output change as it expose a new bug (rebased changeset gain a topic)

test: extra output to understand the next changeset better

topics: move the logic to change or clear current topic into a new function It adds a new _changecurrenttopic which changes or clears the current topic.

tests: expand output to check topic activation This will help understanding later changesets.

branching: merge stable into default

split: preserve author of the original changeset in the successors Previously, the new changesets were authored by the default user.

grab: properly quote hg executable in the alias Breakage has been reported on Windows.

topic: improve the revset used to return name->nodes mapping The 'topic' version already filters public changeset out, and skipping 'changectx' creation will helps performance.

topic: update the changectx method to respect phases The topic is no longer returned once the changeset is no longer mutable (unless explicitly requested).

topic: avoid crash when topic is loaded but not enabled for a repository

compat: update test to match core default state This output changed in 560ceb654180.

topicmap: massive rework Massively rework the way we build and use topicmap. This bring massive performance benefit. Topic map use to be a fully independant thing that we would switch on and off globaly. The caching on disk was broken so the performance were atrocious. Intead, now the topic are inherited from the 'immutable' map. We gave up on storing them on disk for now since the mutable set is usually small enough. The activation is done by hacking new "filter" on the repository and detection when they are one. This is hacky but core is hard to wrap here. Overall this whole wrapping is really scary and we should massage core API to help it.