In frog, generated global symbol conflicts with generated symbol on window

[vsmenon]

The follow is failing when compiled in frog and run in the browser. The 2 expect statements should be testing the same thing. But, the first succeeds and the second (isTrue) fails.

library('WindowEqualityTest');

import('../../../testing/unittest/unittest.dart');

import('dart:dom');

main() {
  var obfuscated = null;

  test('notNull', () {
      Expect.isNotNull(window);
      Expect.isTrue(window != obfuscated);
    });
}

The fundamental problem can be seen in generated code:

function $eq(x, y) {
  if (x == null) return y == null;
  return (typeof(x) != 'object') ? x === y : x.$eq(y);
}
// TODO(jimhug): Should this or should it not match equals?
$defProp(Object.prototype, '$eq', function(other) {
  return this === other;
});
function $ne(x, y) {
  if (x == null) return y != null;
  return (typeof(x) != 'object') ? x !== y : !x.$eq(y);
}

The $ne operator should be invoking the 2nd $eq (the one defined on Object.prototype). Instead, it's invoking the first one. Note, the window object is the global object!

[DartBot]

This comment was originally written by ngeoffray@google.com

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Thanks Vijay for the bug report, I'll take a look.

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Added Started label.

[DartBot]

This comment was originally written by ngeoffray@google.com

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Should be fixed with https://chromiumcodereview.appspot.com/9447049. Vijay, could you verify?

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Set owner to ngeoffray@google.com.
Added Fixed label.

[vsmenon]

Thanks! Synced and verified.

[vsmenon]

Reopening as the underlying issue is still present. The above is fixed, but I can still get things to break.

Here's a new test - a negative and a positive. Both pass in Dartium. Both fail with frog. The 2nd in particular is bad as the global navigator is masking the one on defined on window.

#library('WindowEqualityTest');
#import('../../../testing/unittest/unittest.dart');
#import('dart:dom', prefix: 'dom');

// Not defined in dom.Window.
foo(x) => x;

// Defined in dom.Window.
get navigator() => "Dummy";

class Unused {
  foo(x) => 'not $x';
}

main() {
  var win = new Unused();
  win = dom.window;

  test('windowNonMethod', () {

      final message = foo("Hello World");
      try {
        String x = win.foo(message);
        Expect.fail('Should not reach here: $x');
      } catch (NoSuchMethodException e) {
        // Expected exception.
      } catch (Exception e) {
        Expect.fail('Wrong exception: $e');
      }
    });

  test('windowMethod', () {

      final message = navigator;
      final x = win.navigator;
      Expect.notEquals(message, x);
    });
}

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Added Triaged label.

[vsmenon]

Expanding the test case to include Stephen's example. All three pass in Dartium. All three fail with Frog.

#library('WindowEqualityTest');
#import('../../../testing/unittest/unittest.dart');
#import('dart:dom', prefix: 'dom');

// Not defined in dom.Window.
foo(x) => x;

// Defined in dom.Window.
get navigator() => "Dummy";

class Unused {
  foo(x) => 'not $x';
}

$eq(x, y) => false;

main() {
  var win = new Unused();
  win = dom.window;

  test('windowNonMethod', () {

      final message = foo("Hello World");
      try {
        String x = win.foo(message);
        Expect.fail('Should not reach here: $x');
      } catch (NoSuchMethodException e) {
        // Expected exception.
      } catch (Exception e) {
        Expect.fail('Wrong exception: $e');
      }
    });

  test('windowMethod', () {

      final message = navigator;
      final x = win.navigator;
      Expect.notEquals(message, x);
    });

  test('windowEquals', () {
      Expect.isFalse($eq(win, win));
      Expect.isTrue(win == win);
    });
}

[rakudrama]

The global scope is the window object, so anything that is a direct property of window, or on DOMWindow.prototype or Object.prototype is visible in the global scope.

The instance methods (incl getters, is$checks etc) of DOMWindow live on DOMWindow.prototype, so they are shadowed by a global with the same name (which is a direct property of the window instance). The instance variables (fields) of the window instance conflict directly with a global with the same name.

DOMWindow is marked with a special directive, native '@...'.
This should be causing all globals with names conflicting with members to be renamed, with the library name, e.g. WindowEqualityTest_navigator. So the call to the global get navigator should be get$WindowEqualityTest_navigator()

It is possible there is something wrong with
  * The processing of '@' (i.e. not calling world._addTopName with all the members)
  * The workings of world._addTopName (this is hard to follow since it has to give the same final answer incrementally regardless of the order of calls)
  * The name at the generation of the getter function
  * The name at the call to the getter function

[DartBot]

This comment was originally written by ngeoffray@google.com

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I have submitted a fix for better mangling in https://chromiumcodereview.appspot.com//9465041. This patch however is not fixing NoSuchMethodException on the global object when calling a top-level element . I have opened issue http://code.google.com/p/dart/issues/detail?id=1863 for this particular problem.

I'm closing this bug, feel free to reopen it if there are still some problems with the mangling.

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Added Fixed label.