---

yaml
---
r: 346866
b: refs/heads/master
c: ef957ca
h: refs/heads/master

Author: bob-wilson

[refs]

@@ -1,5 +1,5 @@
 ---
-refs/heads/master: 9ec0a6cf8039bd87c1a27235f91085be36ce3f9a
+refs/heads/master: ef957ca28e77326aef34f4df6bea201f2f1bf67c
 refs/heads/master-next: 203b3026584ecad859eb328b2e12490099409cd5
 refs/tags/osx-passed: b6b74147ef8a386f532cf9357a1bde006e552c54
 refs/tags/swift-2.2-SNAPSHOT-2015-12-01-a: 6bb18e013c2284f2b45f5f84f2df2887dc0f7dea

trunk/utils/round-trip-syntax-test

@@ -76,9 +76,12 @@ class RoundTripTask(object):
 
         contents = ''.join(map(lambda l: l.decode('utf-8', errors='replace'),
                                open(self.input_filename).readlines()))
-        lines = difflib.unified_diff(contents,
-                                     self.stdout.decode('utf-8',
-                                                        errors='replace'),
+        stdout_contents = self.stdout.decode('utf-8', errors='replace')
+
+        if contents == stdout_contents:
+            return None
+
+        lines = difflib.unified_diff(contents, stdout_contents,
                                      fromfile=self.input_filename,
                                      tofile='-')
         diff = '\n'.join(line for line in lines)