diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -787,7 +787,7 @@ class localrepository(repo.repository):
                 update_dirstate = True
 
                 if (not force and p2 != nullid and
-                    (match.files() or match.anypats())):
+                    (match and (match.files() or match.anypats()))):
                     raise util.Abort(_('cannot partially commit a merge '
                                        '(do not specify files or patterns)'))
             else:
diff --git a/tests/test-transplant b/tests/test-transplant
--- a/tests/test-transplant
+++ b/tests/test-transplant
@@ -96,3 +96,21 @@ hg transplant 1
 hg transplant --continue
 hg transplant 1:3
 hg locate
+cd ..
+
+# Test transplant --merge (issue 1111)
+echo % test transplant merge
+hg init t1111
+cd t1111
+echo a > a
+hg ci -Am adda
+echo b >> a
+hg ci -m appendb
+echo c >> a
+hg ci -m appendc
+hg up -C 0
+echo d >> a
+hg ci -m appendd
+echo % tranplant
+hg transplant -m 1
+cd ..
diff --git a/tests/test-transplant.out b/tests/test-transplant.out
--- a/tests/test-transplant.out
+++ b/tests/test-transplant.out
@@ -129,3 +129,10 @@ 0282d5fbbe02 transplanted to 77418277ccb
 added
 bar
 foo
+% test transplant merge
+adding a
+1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+created new head
+% tranplant
+applying 42dc4432fd35
+1:42dc4432fd35 merged at a9f4acbac129