merge: require --force when there are deleted files

mercurial/merge.py

@@ -609,7 +609,7 b' def update(repo, node, branchmerge, forc'
             raise util.Abort(_("update spans branches, use 'hg merge' "
                                "or 'hg update -C' to lose changes"))
         if branchmerge and not forcemerge:
-            if wc.files():
+            if wc.files() or wc.deleted():
                 raise util.Abort(_("outstanding uncommitted changes"))
 
         ### calculate phase

tests/test-merge-force

@@ -17,7 +17,8 b' hg up -qC 1'
 rm a
 
 echo '% local deleted a file, remote removed'
-hg -v merge
+hg merge # should fail, since there are deleted files
+hg -v merge --force
 echo % should show a as removed
 hg st
 

tests/test-merge-force.out

@@ -1,4 +1,5 b''
 % local deleted a file, remote removed
+abort: outstanding uncommitted changes
 resolving manifests
 removing a
 0 files updated, 0 files merged, 1 files removed, 0 files unresolved