diff --git a/hgext/rebase.py b/hgext/rebase.py
--- a/hgext/rebase.py
+++ b/hgext/rebase.py
@@ -565,10 +565,11 @@ def restorestatus(repo):
 def abort(repo, originalwd, target, state):
     'Restore the repository to its original state'
     dstates = [s for s in state.values() if s != nullrev]
-    if [d for d in dstates if not repo[d].mutable()]:
-        repo.ui.warn(_("warning: immutable rebased changeset detected, "
-                       "can't abort\n"))
-        return -1
+    immutable = [d for d in dstates if not repo[d].mutable()]
+    if immutable:
+        raise util.Abort(_("can't abort rebase due to immutable changesets %s")
+                         % ', '.join(str(repo[r]) for r in immutable),
+                         hint=_('see hg help phases for details'))
 
     descendants = set()
     if dstates:
diff --git a/tests/test-rebase-interruptions.t b/tests/test-rebase-interruptions.t
--- a/tests/test-rebase-interruptions.t
+++ b/tests/test-rebase-interruptions.t
@@ -248,7 +248,8 @@ Change phase on B and B'
 Abort the rebasing:
 
   $ hg rebase --abort
-  warning: immutable rebased changeset detected, can't abort
+  abort: can't abort rebase due to immutable changesets 45396c49d53b
+  (see hg help phases for details)
   [255]
 
   $ hg tglogp