evolve: close transaction if conflict is detected in relocate (issue4966) Before this patch, transaction is aborted, if conflict is detected at merging while "hg evolve". Since 8f2ff40fe9c9 (or 3.6) of Mercurial, aborting transaction discards all dirstate changes inside transaction scope for "transactional dirstate" (see below wiki page for detail about it). https://mercurial.selenic.com/wiki/DirstateTransactionPlan Therefore, just aborting transaction causes unchanged (and unexpected) dirstate, even though subsequent commands require dirstate changes while "hg evolve". To keep dirstate changes while "hg evolve", this patch closes current running transaction, if conflict is detected in relocate(), even though exception is raised as usual. Even though "save dirstate and restore it after aborting transaction" like shelve._aborttransaction() of Mercurial can also solve this issue, this patch chose closing transaction for similarity with failure for conflict at "hg unshelve". In addition to it, closing transaction can keep any previous (implicit) changes. In newly added test, there is an additional ancestor revision, which "will be evolved safely". It is used to examine whether failure for conflict doesn't discard already relocated revision(s) while "hg evolve". It is fact for current implementation that "hg evolve" relocates each revisions in separated transactions and already relocated ones are never discarded, even if subsequent relocation fails. Though, this examination is useful to detect unintentional regression in the future.

evolve: remove meaningless transaction nesting Before this patch, functions below nest transaction scope, even though they are invoked only inside a transaction scope created at _solveone(). - _solvebumped() - _solvedivergent() - relocate() via _solveunstable() or _solvebumped() Transaction nesting is useful for localizing "success" (e.g. one scope per commit inside wider scope for multiple committing). But such nesting is redundant for _solveone(), because there is no code path, which causes failure after successfully closing inner transaction(s). In addition to it, this nesting makes it complicated to close current transaction successfully with exception raising inside inner scope, like "hg shelve" at detection of conflicts. "tr.close()" is required at each outer scopes for such case. To remove meaningless transaction nesting, this patch replaces repo.transaction() in functions above by repo.currenttransaction(). This reuses transaction created at _solveone(). This patch also adds 'assert tr' after getting current running transaction, to avoid invocation of functions above without transaction.

evolve: extract logic to new method _evolvemerge This patch introduces a new method _evolvemerge to merge orig to dest in relocate method. This simplifies the code of the method relocate and allows us to re-use it later in the scope of the rework of 'hg evolve --continue'

test: add extra expected output (I forgot to amend...)