test: cleanup title and doc phase-divergent cases

test: remove remaining duplicated file This file should have been removed in d02a7c8cdee5.

test: add test for content-divergence with file removal File addition/removal tends to introduce corner case. The actual test content comes from a Martin von Zweigbergk changesets.

test: clarify changeset concent in the first content-divergence test

branching: merge with stable merge with new changeset on stable.

branching: merge with test consolidation Conflict were simple once isolated.

branching: merge with stable This merge happens before the large test consolidation on stable.

compat: drop getcachevfs, repo.cachevfs is supported in hg 4.4

evolve: when using evolve, cache files belong into the master repo

changelog: mention issue6089 fix

pick: update working dir branch (issue6089) Previously the working copy was left in an "inconsistent" state.

tests: rename test-grab to test-pick This match the new command name.

evolve: make sure div resolution don't replace the initial author (issue6113) Before this patch, divergence resolution logic taking the current user who is running the resolution command as the author of commit that will be created after merging the two divergent csets. This patch make sure that we preserve the initial author. Changes in test file reflect the fixed behaviour.

evolve: add test which demonstrate issue6113 This patch introducing a new test file which contains the test for issue6113 which is `test-evolve-content-divergent-distributed.t`. This test file is supposed to contain tests for distributed workflows. Next patch will fix the bug.

test: consolidate the content-divergent test cases This commit move most of the content divergent related test in dedicated and thematic test files.

changelog: mention the fix to issue6057

extensions: avoid enabling evolve for unrelated repositories (issue6057) The support for the `experimental.evolve` config have been there forever. So we can stop using the global variable. This help avoiding evolve to enable itself of repository that did not explicitly activated it. For example, this is useful for hgwebdir. Before this change, evolution feature had to be explicitly disabled or enabled in every single repository.

stack: improve set combination logic

stack: fix phasecache._phasesets check logic When _phasesets is not None, it's a list, and it contains set()s of revisions in a specific phase, starting from public, draft, secret and so on. But since repos are supposed to have the majority of revisions in public phase, the first element of this list is not a (potentially huge) set, but None. Previously this code tried to check if there's any element that is None, and was always finding None at index 0, so the short path was executed every time and the rest of the function was never used.

evolve: remove todo markers from a test which has been fixed

next: clarify tests related to `commands.update.check` test This clarify the test and help understand the next changeset.

stack: simplify phasecache checks in _stackcandidates()

evolve: fix divergence resolution when not merging a descendant In divergence resolution, when we merge other cset with divergent one we pass a `mergeancestor` arg to merge.update() and before this patch we were passing `mergeancestor` as True in every case. But it should be True only when we are merging a descendant onto an ancestor. When mergeancestor is True it does two things: 1) allows the merge if the destination is the same as the parent of the ctx (so we can use graft to copy commits) 2) informs update that the incoming changes are newer than the destination so it doesn't prompt about "remote changed foo which local deleted". So this patch change it to pass `mergeancestor` as True only when it is required. And changes in test file shows that it wasn't prompting either in those cases when it should (acc. to 2nd point) Test written by Pierre-Yves David, based the one updated in 5dbaabfe2c59.

test: fix a phase divergence test case to actually not contains conflict The previous test case had a conflict, but that conflict is currently not raise by phase divergence resolution. This is an independent bug to solve.

tests: use current instability names everywhere

test: apply unstability resolution to `test-unstability-resolution-result.t` The test cases in this file probably deserved to be dispatched in other more thematic test file.

test: rename and clarify content of test-unstable-content-divergent.t The troubles → instabilities renaming was not applied here.

test: rename and clarify content of test-unstable-orphan.t The troubles → instabilities renaming was not applied here.

evolve: refactor the code which swap two nodes (in divergence resolution) I see that we are using the code to swap the "divergent" and "other" node; and updating the evolvestate accordingly at many places in divergence resolution. This patch extract that code to a function. Although I don't have strong opinion on this patch. It's a volunteered patch to remove some redundancy.

evolve: remove tmpctx arg from _resolvephasedivergent() Before this patch, in _resolvephasedivergent() function we were passing an optional argument "tmpctx" which was used to store a rebased version of bumped if required. But for sake of simplicity we can achieve the same results even without passing this "tmpctx" into that function. No changes in test files demonstrate that this patch don't break anything.

doc: clarify _resolvephasedivergent role and constraint Small documentation patch before larger changes.

branching: merge with stable