diff -r bd33e749dfcc -r f47a5f990eb2 hgext/states.py
--- a/hgext/states.py	Mon Sep 12 19:35:50 2011 +0200
+++ b/hgext/states.py	Mon Sep 12 23:47:06 2011 +0200
@@ -247,6 +247,13 @@
 
     - add ``<state>()`` directives that match all node in a state.
 
+Other extensions
+................
+
+:Rebase:     can't rewrite unpublished changeset.
+
+
+
 Implementation
 ==============
 
@@ -634,6 +641,22 @@
     h = repo.stateheads(st)
     return wireproto.encodelist(h) + "\n"
 
+# Other extension support
+#########################
+
+def wraprebasebuildstate(orig, repo, *args, **kwargs):
+   result = orig(repo, *args, **kwargs)
+   if result is not None:
+        revs = result[2]
+        base = repo.changelog.node(min(result[2]))
+        state = repo.nodestate(base)
+        if not state.properties & _MUTABLE:
+            raise util.Abort(_('can not rebase published changeset %s')
+                             % node.short(base),
+                             hint=_('see `hg help --extension states` for details'))
+   return result
+
+
 def uisetup(ui):
     """
     * patch stuff for the _NOSHARE property
@@ -656,6 +679,12 @@
     for state in STATES:
         if state.trackheads:
             revset.symbols[state.headssymbol] = state._revsetheads
+    try:
+        rebase = extensions.find('rebase')
+        if rebase:
+            extensions.wrapfunction(rebase, 'buildstate', wraprebasebuildstate)
+    except KeyError:
+        pass # rebase not found