mq: qnew -f should reject merge working directories

hgext/mq.py

@@ -770,6 +770,10 b' class queue(object):'
         else:
             m, a, r, d = self.check_localchanges(repo, force)
             match = cmdutil.matchfiles(repo, m + a + r)
+        if force:
+            p = repo[None].parents()
+            if len(p) > 1:
+                raise util.Abort(_('cannot manage merge changesets'))
         commitfiles = m + a + r
         self.check_toppatch(repo)
         insert = self.full_series_end()

tests/test-mq-qnew

@@ -58,3 +58,19 b' cat ../.hg/patches/p'
 echo '% qnew -u with no username configured'
 HGUSER= hg qnew -u blue red
 cat ../.hg/patches/red
+
+echo '% fail when trying to import a merge'
+hg init merge
+cd merge
+touch a
+hg ci -Am null
+echo a >> a
+hg ci -m a
+hg up -r 0
+echo b >> a
+hg ci -m b
+hg merge -f 1
+hg resolve --mark a
+hg qnew -f merge
+
+exit 0

tests/test-mq-qnew.out

@@ -35,3 +35,13 b' diff --git a/d/b b/d/b'
 % qnew -u with no username configured
 From: blue
 
+% fail when trying to import a merge
+adding a
+1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+created new head
+merging a
+warning: conflicts during merge.
+merging a failed!
+0 files updated, 0 files merged, 0 files removed, 1 files unresolved
+use 'hg resolve' to retry unresolved file merges or 'hg update -C' to abandon
+abort: cannot manage merge changesets