Add assert message.

diff --git a/buildfarm/build.py b/buildfarm/build.py
index 7c371b15239390f44e93b531d734f111e7f4ec3c..28ff6d9c9d298a125cc606ea9423707519000893 100644 (file)
--- a/buildfarm/build.py
+++ b/buildfarm/build.py
@@ -132,7 +132,7 @@ class BuildStatus(object):
             return True
         for ((old_name, old_result), (new_name, new_result)) in zip(
             older.stages, self.stages):
-            assert old_name == new_name
+            assert old_name == new_name, "build stage name mismatch: %s != %s" % (old_name, new_name)
             if new_result == old_result:
                 continue
             if new_result < 0 and old_result >= 0: