#
#
# patch "cmd_merging.cc"
#  from [6ee48e48d6ab44eb64335ee5fefc0f1bc0e3a4cb]
#    to [546983474b5af1e3b529f2a01d0a54f6918f190f]
# 
# patch "tests/noop_merge_into_workspace/__driver__.lua"
#  from [c35b200e70b0ba653022eec3e5da6939e335a306]
#    to [6b3882799c8273d99fbe9a4fe3d8aca06cd68c73]
#
============================================================
--- cmd_merging.cc	6ee48e48d6ab44eb64335ee5fefc0f1bc0e3a4cb
+++ cmd_merging.cc	546983474b5af1e3b529f2a01d0a54f6918f190f
@@ -743,6 +743,12 @@ CMD(merge_into_workspace, "merge_into_wo
   N(!(left_id == right_id),
     F("workspace is already at revision %s") % left_id);
 
+  N(!is_ancestor(db, right_id, left_id),
+    F("revision %s is already an ancestor of your workspace") % right_id);
+  N(!is_ancestor(db, left_id, right_id),
+    F("revision %s is a descendant of the workspace parent,\n"
+      "did you mean 'mtn update -r %s'?") % right_id % right_id);
+
   P(F("[left]  %s") % left_id);
   P(F("[right] %s") % right_id);
 
============================================================
--- tests/noop_merge_into_workspace/__driver__.lua	c35b200e70b0ba653022eec3e5da6939e335a306
+++ tests/noop_merge_into_workspace/__driver__.lua	6b3882799c8273d99fbe9a4fe3d8aca06cd68c73
@@ -10,5 +10,5 @@ check(mtn("merge_into_workspace", parent
 
 check(mtn("merge_into_workspace", parent), 1, nil, false)
 
-check(mtn("update", "--revision", parent), 0, false)
+check(mtn("update", "--revision", parent), 0, false, false)
 check(mtn("merge_into_workspace", child), 1, nil, false)