evolve: orphans that evolve into nothing don't need successors (issue5967) When continuing to solve an orphan that created no changes (i.e. clean wdir), _completeorphan() used to create an obsmarker that said that the result of that orphan evolution is the currently checked out changeset. That's not a correct obsmarker, because all of the orphan's changes were dropped and so it had no effect on the currently checked out changeset. This is an issue that has only existed when --continu'ing evolve, that's why the fix touches _completeorphan(), but not _solveunstable(). This fix is adapted from a similar "if node is None" block in _finalizerelocate().

tests: demonstrate obsmarker creation after discarding conflicting changes Continued evolve creates an incorrect obsmarker that says 2 is a successor of 1. It's incorrect because 1 was dropped as it created no changes to commit (after conflict resolution that discarded its changes). If evolve does the same thing in one go (e.g. just by using --tool :local and without subsequent need to continue) the obsmarker is correct.

pick: remove transaction on the whole command (issue6037) At its core, pick is a pretty straightforward and well-behaving command, it uses functions already in core hg, it checks that wdir is clean and that changeset to pick is not public, it checks if there happen to be merge conflicts and can be --continue'd later, etc. It is very similar to graft in core (it also uses mergemod.graft function), but it obsoletes the original changeset. However, graft does not experience this incorrect behavior from issue 6037. What happens in the test case for this issue when we pick a revision that touches both "a" and "b": mergemod.graft() takes the original changeset and tries to apply it to the wdir, which results in "b" being marked as newly added and ready to be committed, "a" updated with the new content and being marked as modified, but "a" also has conflicts. Pick correctly notices this and saves its state before asking for user intervention. So far so good. However, when the command raises InterventionRequired to print a user-facing message and exit while being wrapped in repo.transaction() context manager, the latter partially undoes what mergemod.graft() did: it unmarks "b" as added. And when user continues pick, "b" is therefore not tracked and is not included in the resulting commit. The transaction is not useful here, because it doesn't touch wdir (it's still dirty), it doesn't remove pickstate (and other commands will refuse to work until pick --abort or --continue), it just makes "b" untracked. The solution is to use repo.transaction() only to wrap code that writes data to hg store in the final stages of the command after all checks have passed and is not expected to fail on trivial cases like merge conflicts. For example, committing the picked changeset. But since pick uses repo.commit() for that, and because that function already uses a transaction, wrapping it in another transaction doesn't make sense.