rebase: do not retract phase boundary by hand

We rely on the internal mechanism to commit the changeset in the right phase.
This similar to what the mq extension is doing.

This is an important change as we plan to includes phase movement within the
transaction. Avoiding phase movement from high-level code will avoid the
burden of transaction handling. It is also important to limit the need for
transaction handling as this limits the odds of people messing up. Most common
expected mess-up is code using a different transaction for changeset creation
and phase adjustment.

hgext/rebase.py

@@ -469,15 +469,18 b' def concludenode(repo, rev, p1, p2, comm'
         extra = {'rebase_source': ctx.hex()}
         if extrafn:
             extrafn(ctx, extra)
-        # Commit might fail if unresolved files exist
-        newrev = repo.commit(text=commitmsg, user=ctx.user(),
-                             date=ctx.date(), extra=extra, editor=editor)
+
+        backup = repo.ui.backupconfig('phases', 'new-commit')
+        try:
+            targetphase = max(ctx.phase(), phases.draft)
+            repo.ui.setconfig('phases', 'new-commit', targetphase, 'rebase')
+            # Commit might fail if unresolved files exist
+            newrev = repo.commit(text=commitmsg, user=ctx.user(),
+                                 date=ctx.date(), extra=extra, editor=editor)
+        finally:
+            repo.ui.restoreconfig(backup)
+
         repo.dirstate.setbranch(repo[newrev].branch())
-        targetphase = max(ctx.phase(), phases.draft)
-        # retractboundary doesn't overwrite upper phase inherited from parent
-        newnode = repo[newrev].node()
-        if newnode:
-            phases.retractboundary(repo, targetphase, [newnode])
         return newrev
     except util.Abort:
         # Invalidate the previous setparents