diff mercurial/commands.py @ 26303:c99b4d6efdd8

merge: move default destination computation in a revset

This is another step toward having "default" destination more clear and unified.

--- a/mercurial/commands.py	Thu Sep 17 12:44:52 2015 -0700
+++ b/mercurial/commands.py	Thu Sep 17 14:03:15 2015 -0700
@@ -4768,58 +4768,8 @@
     if node:
         node = scmutil.revsingle(repo, node).node()
 
-    if not node and repo._activebookmark:
-        bmheads = repo.bookmarkheads(repo._activebookmark)
-        curhead = repo[repo._activebookmark].node()
-        if len(bmheads) == 2:
-            if curhead == bmheads[0]:
-                node = bmheads[1]
-            else:
-                node = bmheads[0]
-        elif len(bmheads) > 2:
-            raise util.Abort(_("multiple matching bookmarks to merge - "
-                "please merge with an explicit rev or bookmark"),
-                hint=_("run 'hg heads' to see all heads"))
-        elif len(bmheads) <= 1:
-            raise util.Abort(_("no matching bookmark to merge - "
-                "please merge with an explicit rev or bookmark"),
-                hint=_("run 'hg heads' to see all heads"))
-
-    elif not node:
-        branch = repo[None].branch()
-        bheads = repo.branchheads(branch)
-        nbhs = [bh for bh in bheads if not repo[bh].bookmarks()]
-
-        if len(nbhs) > 2:
-            raise util.Abort(_("branch '%s' has %d heads - "
-                               "please merge with an explicit rev")
-                             % (branch, len(bheads)),
-                             hint=_("run 'hg heads .' to see heads"))
-
-        parent = repo.dirstate.p1()
-        if len(nbhs) <= 1:
-            if len(bheads) > 1:
-                raise util.Abort(_("heads are bookmarked - "
-                                   "please merge with an explicit rev"),
-                                 hint=_("run 'hg heads' to see all heads"))
-            if len(repo.heads()) > 1:
-                raise util.Abort(_("branch '%s' has one head - "
-                                   "please merge with an explicit rev")
-                                 % branch,
-                                 hint=_("run 'hg heads' to see all heads"))
-            msg, hint = _('nothing to merge'), None
-            if parent != repo.lookup(branch):
-                hint = _("use 'hg update' instead")
-            raise util.Abort(msg, hint=hint)
-
-        if parent not in bheads:
-            raise util.Abort(_('working directory not at a head revision'),
-                             hint=_("use 'hg update' or merge with an "
-                                    "explicit revision"))
-        if parent == nbhs[0]:
-            node = nbhs[-1]
-        else:
-            node = nbhs[0]
+    if not node:
+        node = scmutil.revsingle(repo, '_mergedefaultdest()').node()
 
     if opts.get('preview'):
         # find nodes that are ancestors of p2 but not of p1