From b35a971e63193d9f0dd1242b99bf68ec99ab1bde Mon Sep 17 00:00:00 2001
From: Tim Blasi <tjblasi@google.com>
Date: Thu, 28 Jan 2016 12:14:36 -0800
Subject: [PATCH] refactor(dart/transform): Error in name convert funcs on
 unexpected input

Issue raised in PR #6745.
Previously, the transformer name conversion functions could return the
input string on unexpected input, which is almost certainly an error.

`throw` in this case instead, so we know early that something has likely
gone wrong.
---
 modules_dart/transform/lib/src/transform/common/names.dart | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/modules_dart/transform/lib/src/transform/common/names.dart b/modules_dart/transform/lib/src/transform/common/names.dart
index 1cc42f1f47c7..99a2c4d40834 100644
--- a/modules_dart/transform/lib/src/transform/common/names.dart
+++ b/modules_dart/transform/lib/src/transform/common/names.dart
@@ -83,5 +83,9 @@ String _toExtension(
           '$toExtension';
     }
   }
-  return uri;
+  throw new ArgumentError.value(
+      uri,
+      'uri',
+      'Provided value ends with an unexpected extension. '
+      'Expected extension(s): [${fromExtensions.join(', ')}].');
 }