Check for duplicate library names

lib/src/codegen/js_codegen.dart

 // Copyright (c) 2015, 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.
 
 library dev_compiler.src.codegen.js_codegen;
 
 import 'dart:collection' show HashSet, HashMap;
 
 import 'package:analyzer/analyzer.dart' hide ConstantEvaluator;
 import 'package:analyzer/src/generated/ast.dart' hide ConstantEvaluator;
@@ skipping 96 matching lines @@
     new CoercionReifier(library, compiler).reify();
 
     var unit = library.library;
     if (unit.directives.isNotEmpty) {
       var libraryDir = unit.directives.first;
       if (libraryDir is LibraryDirective) {
         var jsName = getAnnotationValue(libraryDir, _isJsNameAnnotation);
         jsDefaultValue = getConstantField(jsName, 'name', types.stringType);
       }
     }
-    if (jsDefaultValue == null) jsDefaultValue = '{}';
 
     // TODO(jmesserly): visit scriptTag, directives?
 
     _loader.collectElements(currentLibrary, library.partsThenLibrary);
 
     for (var unit in library.partsThenLibrary) {
       _constField = new ConstFieldVisitor(types, unit);
 
       for (var decl in unit.declarations) {
         if (decl is TopLevelVariableDeclaration) {
@@ skipping 27 matching lines @@
     _qualifiedIds.forEach(unqualifyIfNeeded);
     _qualifiedGenericIds.forEach(unqualifyIfNeeded);
 
     if (_exports.isNotEmpty) _moduleItems.add(js.comment('Exports:'));
 
     // TODO(jmesserly): make these immutable in JS?
     for (var name in _exports) {
       _moduleItems.add(js.statement('#.# = #;', [_exportsVar, name, name]));
     }
 
     var name = new JS.Identifier(jsLibraryName(currentLibrary));

[Jennifer Messerly, 2015/06/05 16:22:27]

suggestion, maybe build the Identifier later, and have `name` store the String?

String name = jsLibraryName(currentLibrary);


That way the string can be used directly, instead of `name.name`

I think in most places, js_ast will implicitly convert the string to an
identifier (for better or worse), but if needed, could do:

var nameId = new JS.Identifier(name);

[vsm, 2015/06/05 17:01:04]

Done.

+    var jsName = js.string(name.name, "'");
 
     // TODO(jmesserly): it would be great to run the renamer on the body,
     // then figure out if we really need each of these parameters.
     // See ES6 modules: https://github.com/dart-lang/dev_compiler/issues/34
     var program = [
-      js.statement('var # = dart.defineLibrary(#, #);', [
-        name,
-        name,
-        js.call(jsDefaultValue)
-      ])
+      jsDefaultValue != null
+          ? js.statement(
+              'dart.defineLibrary(#, #);', [jsName, js.call(jsDefaultValue)])
+          : js.statement('dart.defineLibrary(#);', [jsName])
     ];
 
     var params = [_exportsVar];
     var args = [name];
     _imports.forEach((library, temp) {
       var name = new JS.Identifier(temp.name);
       params.add(temp);
       args.add(name);
       var helper = _loader.libraryIsLoaded(library) ? 'import' : 'lazyImport';
-      program.add(js.statement('var # = dart.#(#);', [name, helper, name]));
+      program
+          .add(js.statement('dart.#(#);', [helper, js.string(name.name, "'")]));
     });
 
     program.add(js.statement("(function(#) { 'use strict'; #; })(#);", [
       params,
       _moduleItems,
       args
     ]));
 
     return new JS.Program(program);
   }
@@ skipping 2454 matching lines @@
 
 /// A special kind of element created by the compiler, signifying a temporary
 /// variable. These objects use instance equality, and should be shared
 /// everywhere in the tree where they are treated as the same variable.
 class TemporaryVariableElement extends LocalVariableElementImpl {
   TemporaryVariableElement.forNode(Identifier name) : super.forNode(name);
 
   int get hashCode => identityHashCode(this);
   bool operator ==(Object other) => identical(this, other);
 }