Hashcodes were being improperly calculated for public API of libraries.

compiler/javatests/com/google/dart/compiler/end2end/inc/IncrementalCompilationTest.java

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 package com.google.dart.compiler.end2end.inc;
 
 import static com.google.dart.compiler.DartCompiler.EXTENSION_API;
 import static com.google.dart.compiler.DartCompiler.EXTENSION_DEPS;
 import static com.google.dart.compiler.backend.js.JavascriptBackend.EXTENSION_APP_JS;
 import static com.google.dart.compiler.backend.js.JavascriptBackend.EXTENSION_JS;
@@ skipping 156 matching lines @@
 
     didNotWrite("some.dart", EXTENSION_JS, provider);
     didNotWrite("some.lib.dart", EXTENSION_API, provider);
     didNotWrite("some.lib.dart", EXTENSION_DEPS, provider);
 
     didNotWrite("myother0.dart", EXTENSION_JS, provider);
     didNotWrite("myother1.dart", EXTENSION_JS, provider);
     didNotWrite("myother2.dart", EXTENSION_JS, provider);
   }
 
+  public void testNormalizationTracking() {
+    compile();
+
+    provider.resetReadsAndWrites();
+    myAppSource.touchSource("myother7.dart");
+    compile();
+
+    // Test against normalization having an effect on hashcodes
+    // SomeInterface2 is an empty interface that can have an extra default constructor added by 
+    // the dartc backend normalization process.  By depending on a class that implements the interface,
+    // my.app.dart.deps will transitively depend on the empty interface.  If something changes
+    // with how hashcodes are generated, this test should be updated.
+
+    // We just bumped the timestamp on myother7.dart, so only myother7.dart.js and my.app.js should
+    // be changed. At present, the app's deps and api will be rewritten.
+
+    didWrite("myother7.dart", EXTENSION_JS, provider);
+    didWrite("my.app.dart", EXTENSION_APP_JS, provider);
+    didWrite("my.app.dart", EXTENSION_DEPS, provider);
+    didWrite("my.app.dart", EXTENSION_API, provider);
+
+    // Nothing else should have changed.
+    didNotWrite("my.dart", EXTENSION_JS, provider);
+    didNotWrite("someimpl.dart", EXTENSION_JS, provider);
+    didNotWrite("someimpl.lib.dart", EXTENSION_API, provider);
+    didNotWrite("someimpl.lib.dart", EXTENSION_DEPS, provider);
+
+    didNotWrite("some.dart", EXTENSION_JS, provider);
+    didNotWrite("some.lib.dart", EXTENSION_API, provider);
+    didNotWrite("some.lib.dart", EXTENSION_DEPS, provider);
+
+    didNotWrite("myother0.dart", EXTENSION_JS, provider);
+    didNotWrite("myother1.dart", EXTENSION_JS, provider);
+    didNotWrite("myother2.dart", EXTENSION_JS, provider);
+  }
+
   public void testKnockout_jsArtifact() {
     compile();
 
     provider.resetReadsAndWrites();
     provider.removeArtifact("my.dart", "", EXTENSION_JS);
     compile();
 
     // At present, knocking out a js artifact will force an update of the library's api and
     // deps. This could be optimized.
     didWrite("my.dart", EXTENSION_JS, provider);
@@ skipping 529 matching lines @@
   private void didWrite(String sourceName, String extension, IncMockArtifactProvider provider) {
     String spec = sourceName + "/" + extension;
     assertTrue("Expected write: " + spec, provider.writes.contains(spec));
   }
 
   private void didNotWrite(String sourceName, String extension, IncMockArtifactProvider provider) {
     String spec = sourceName + "/" + extension;
     assertFalse("Didn't expect write: " + spec, provider.writes.contains(spec));
   }
 }