diff --git a/build.json b/build.json
index e8820b359e7f27b9d25cc7a675531f33bcbd4afd..291c7e6f53cc5f951ba8b5e309a80844b2aaf5ed 100644
--- a/build.json
+++ b/build.json
@@ -420,9 +420,9 @@
       "build": "private",
       "language": "c++",
       "src": [
+        "test/cpp/util/messages.proto",
         "test/cpp/util/echo.proto",
         "test/cpp/util/echo_duplicate.proto",
-        "test/cpp/util/messages.proto",
         "test/cpp/end2end/async_test_server.cc",
         "test/cpp/util/create_test_channel.cc"
       ]
@@ -432,8 +432,8 @@
       "build": "private",
       "language": "c++",
       "src": [
-        "examples/tips/empty.proto",
         "examples/tips/label.proto",
+        "examples/tips/empty.proto",
         "examples/tips/pubsub.proto",
         "examples/tips/client.cc"
       ],
diff --git a/tools/buildgen/build-cleaner.py b/tools/buildgen/build-cleaner.py
index f9307360c328d5173a59009ff35513565730bfdb..4992beb89707c8c06084e7681db3ada3b548d460 100755
--- a/tools/buildgen/build-cleaner.py
+++ b/tools/buildgen/build-cleaner.py
@@ -33,9 +33,9 @@ def clean_elem(indict):
   for name in ['public_headers', 'headers', 'src']:
     if name not in indict: continue
     inlist = indict[name]
-    protos = set(x for x in inlist if os.path.splitext(x)[1] == '.proto')
+    protos = list(x for x in inlist if os.path.splitext(x)[1] == '.proto')
     others = set(x for x in inlist if x not in protos)
-    indict[name] = sorted(protos) + sorted(others)
+    indict[name] = protos + sorted(others)
   return rebuild_as_ordered_dict(indict, _ELEM_KEYS)
 
 for filename in sys.argv[1:]: