tests: add a test file of resolving orphaness of merge changesets This patch adds a new test file named test-evolve-orphan-merge.t which contains test cases when `hg evolve` try to stabilize a merge changeset which was orphan. This file contains 20-30% of all the cases as we have got something to fix before we add tests for rest of the cases. Going by this approach will make sure we don't live unfixed cases in the test file and the test files does not become a pile of hacks which are used to get in state when we fix the bugs.

grab: gracefully handle the case when we try to grab parent of wdir Before this patch, we go all the way down to obsmarker creation logic and gets an error saying that changeset cannot obsolete itself. We should be more smart here and error out early saying we cannot grab that changeset.

grab: move the initialization of pctx variable outside of if-else The pctx variable is used outside of the if-else but it was initialized under the conditional statements. Added test for the case when the initialization inside the if-else broke `hg grab --continue`.

compat: drop hack around http request handling for 4.6 The approach we used in 4.5 works again :-)

obsdiscovery: add compatibility layer to register wireproto command Mercurial core 0b18604db95e changed the way permissions are registered.

compat: pass all hgweb dispatch argument to the orig function This make use compatible with whatever changes on this side.

grab: add short version for continue and abort

obsdiscovery: include units in ui.progress() calls (issue5773)

tests: commit tests changes missing in the previous changeset (guess who forgot to amend)...

obslog: add the operation to the Obslog output The operation is helpful when debugging a case where we don't know how we ended up in this case while effect-flag are useful to understand what semantic changes happens to a changeset. Add the operation when displaying an obs-marker in the following form: `rewritten as X using amend` The other proposal is interesting but seems harder to internationalize and might requires update each time we introduce new operation: `Amended as X` Let's use the first proposal right now.

serverminitopic: attempt to fix assertion for repoview in branchmap This seems fine since we topic never impact public only caches.

compat: register a version of 'obsfatedata' template that works with 4.6 Since showlist is deprecated, let us use compatlist.

compat: register a version of 'troubles' template that works with 4.6 API Since showlist is deprecated, let us use compatlist.

exthelper: add support for "requires" argument for template keyword This will help use to support the new template API.