--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -324,12 +324,13 @@ class changeset_printer(object):
 
         parents = log.parentrevs(rev)
         if not self.ui.debugflag:
-            parents = [p for p in parents if p != nullrev]
-            if len(parents) == 1 and parents[0] == rev-1:
-                parents = []
+            if parents[1] == nullrev:
+                if parents[0] >= rev - 1:
+                    parents = []
+                else:
+                    parents = [parents[0]]
         parents = [(p, hexfunc(log.node(p))) for p in parents]
 
-
         self.ui.write(_("changeset:   %d:%s\n") % (rev, hexfunc(changenode)))
 
         if branch:

--- a/mercurial/merge.py
+++ b/mercurial/merge.py
@@ -65,8 +65,8 @@ def checkunknown(wctx, mctx):
     for f in wctx.unknown():
         if f in man:
             if mctx.filectx(f).cmp(wctx.filectx(f).data()):
-                raise util.Abort(_("'%s' already exists in the working"
-                                   " dir and differs from remote") % f)
+                raise util.Abort(_("untracked local file '%s' differs"\
+                                   " from remote version") % f)
 
 def forgetremoved(wctx, mctx):
     """

--- a/tests/test-globalopts.out
+++ b/tests/test-globalopts.out
@@ -27,6 +27,7 @@ summary:     b
 %% abbrev of long option
 changeset:   1:b6c483daf290
 tag:         tip
+parent:      -1:000000000000
 user:        test
 date:        Thu Jan 01 00:00:01 1970 +0000
 summary:     b
@@ -49,6 +50,7 @@ 1:b6c483daf290
 %% -v/--verbose
 changeset:   1:b6c483daf290
 tag:         tip
+parent:      -1:000000000000
 user:        test
 date:        Thu Jan 01 00:00:01 1970 +0000
 files:       b

--- a/tests/test-merge1.out
+++ b/tests/test-merge1.out
@@ -10,7 +10,7 @@ diff -r d9e5953b9dec b
 M b
 0 files updated, 0 files merged, 1 files removed, 0 files unresolved
 %% merge should fail
-abort: 'b' already exists in the working dir and differs from remote
+abort: untracked local file 'b' differs from remote version
 %% merge of b expected
 merging for b
 merging b

--- a/tests/test-unrelated-pull.out
+++ b/tests/test-unrelated-pull.out
@@ -11,6 +11,7 @@ added 1 changesets with 1 changes to 1 f
 (run 'hg heads' to see heads, 'hg merge' to merge)
 changeset:   1:bdcee5d51fa6
 tag:         tip
+parent:      -1:000000000000
 user:        a
 date:        Mon Jan 12 13:46:40 1970 +0000
 summary:     a