diff -r 415a51ac07a7 -r 53a6dbc33e36 hgext/evolve.py
--- a/hgext/evolve.py	Mon Sep 14 13:52:34 2015 -0700
+++ b/hgext/evolve.py	Wed Sep 16 17:12:38 2015 -0700
@@ -805,74 +805,75 @@
     nodeid was actually created. If created is False, nodeid
     references a changeset existing before the rewrite call.
     """
-    if len(old.parents()) > 1: #XXX remove this unecessary limitation.
-        raise error.Abort(_('cannot amend merge changesets'))
-    base = old.p1()
-    updatebookmarks = _bookmarksupdater(repo, old.node())
-
-    # commit a new version of the old changeset, including the update
-    # collect all files which might be affected
-    files = set(old.files())
-    for u in updates:
-        files.update(u.files())
-
-    # Recompute copies (avoid recording a -> b -> a)
-    copied = copies.pathcopies(base, head)
-
-
-    # prune files which were reverted by the updates
-    def samefile(f):
-        if f in head.manifest():
-            a = head.filectx(f)
-            if f in base.manifest():
-                b = base.filectx(f)
-                return (a.data() == b.data()
-                        and a.flags() == b.flags())
+    if True:
+        if len(old.parents()) > 1: #XXX remove this unecessary limitation.
+            raise error.Abort(_('cannot amend merge changesets'))
+        base = old.p1()
+        updatebookmarks = _bookmarksupdater(repo, old.node())
+
+        # commit a new version of the old changeset, including the update
+        # collect all files which might be affected
+        files = set(old.files())
+        for u in updates:
+            files.update(u.files())
+
+        # Recompute copies (avoid recording a -> b -> a)
+        copied = copies.pathcopies(base, head)
+
+
+        # prune files which were reverted by the updates
+        def samefile(f):
+            if f in head.manifest():
+                a = head.filectx(f)
+                if f in base.manifest():
+                    b = base.filectx(f)
+                    return (a.data() == b.data()
+                            and a.flags() == b.flags())
+                else:
+                    return False
             else:
-                return False
-        else:
-            return f not in base.manifest()
-    files = [f for f in files if not samefile(f)]
-    # commit version of these files as defined by head
-    headmf = head.manifest()
-    def filectxfn(repo, ctx, path):
-        if path in headmf:
-            fctx = head[path]
-            flags = fctx.flags()
-            mctx = memfilectx(repo, fctx.path(), fctx.data(),
-                              islink='l' in flags,
-                              isexec='x' in flags,
-                              copied=copied.get(path))
-            return mctx
-        return None
-
-    message = cmdutil.logmessage(repo.ui, commitopts)
-    if not message:
-        message = old.description()
-
-    user = commitopts.get('user') or old.user()
-    date = commitopts.get('date') or None # old.date()
-    extra = dict(commitopts.get('extra', {}))
-    extra['branch'] = head.branch()
-
-    new = context.memctx(repo,
-                         parents=newbases,
-                         text=message,
-                         files=files,
-                         filectxfn=filectxfn,
-                         user=user,
-                         date=date,
-                         extra=extra)
-
-    if commitopts.get('edit'):
-        new._text = cmdutil.commitforceeditor(repo, new, [])
-    revcount = len(repo)
-    newid = repo.commitctx(new)
-    new = repo[newid]
-    created = len(repo) != revcount
-    updatebookmarks(newid)
-
-    return newid, created
+                return f not in base.manifest()
+        files = [f for f in files if not samefile(f)]
+        # commit version of these files as defined by head
+        headmf = head.manifest()
+        def filectxfn(repo, ctx, path):
+            if path in headmf:
+                fctx = head[path]
+                flags = fctx.flags()
+                mctx = memfilectx(repo, fctx.path(), fctx.data(),
+                                  islink='l' in flags,
+                                  isexec='x' in flags,
+                                  copied=copied.get(path))
+                return mctx
+            return None
+
+        message = cmdutil.logmessage(repo.ui, commitopts)
+        if not message:
+            message = old.description()
+
+        user = commitopts.get('user') or old.user()
+        date = commitopts.get('date') or None # old.date()
+        extra = dict(commitopts.get('extra', {}))
+        extra['branch'] = head.branch()
+
+        new = context.memctx(repo,
+                             parents=newbases,
+                             text=message,
+                             files=files,
+                             filectxfn=filectxfn,
+                             user=user,
+                             date=date,
+                             extra=extra)
+
+        if commitopts.get('edit'):
+            new._text = cmdutil.commitforceeditor(repo, new, [])
+        revcount = len(repo)
+        newid = repo.commitctx(new)
+        new = repo[newid]
+        created = len(repo) != revcount
+        updatebookmarks(newid)
+
+        return newid, created
 
 class MergeFailure(util.Abort):
     pass