obsolete: detect late comer during push

obsolete: add latecomer computation and display

obsolete: add precursors and successors revset.

update revset vocabulary to use precursors, successors

obsolete: remove unused variable in rebase wrapping

evolve: tidy up a bit - long lines - extra blank lines - commands options descriptions

obsolete: make collapse create less markers Collapsing A and B into C was registering: A -> C B -> C A -> B At this point, the last relation brings nothing and is removed for the sake of simplicity: A -> C B -> C test-evolve.t is slightly modified as one of the relations let stabilize compute a target outside of the parent revision tree. This is a stabilize bug, not trivial to fix, so let's tweak the test for now.

obsolete: remove unused code from reposetup()

obsolete: suspended changeset with secret only children should be secret too test-obsolete-push.t: exhibit outgoing bug with suspended changeset in this case

obsolete: add 'obsolete' keyword The obsolete keyword displays the node status among 'stable', 'unstable', 'suspended', 'extinct'.

obsolete: unify collapsed revisions markers handling When collapsing A, B and C into D, amend was registering: A -> D B -> D A -> B C -> D A -> C while the rebase wrapper was doing: A -> D B -> D C -> D At this point, I have no argument to favor one or another or even a new one like: A -> B B -> C C -> D so I am aligning the rebase implementation on the older amend one. At least we can now change them all at once.

rebase: improve invalid revisions filtering - Filter rebasestate nullmerge and unrebased revision before considering updating obsolete. This simplifies the handling of obsolete and make it ignore unrebased revision rather than extinguishing them. - Apply obsolete markers only if rebasestate is not empty, testing rebasetarget was irrelevant.