Infinite loop in Resolver

[bwilkerson]

The method Resolver.hasRedirectedConstructorCycle(ConstructorElement) contains a loop that will never terminate when there are cyclic references in constructor invocations. This was caught by .../dart/frog/tests/leg_only/src/CyclicConstructorTest.dart.

In this particular case, "next" oscillates between being the element for the constructor named "a" and the constructor named "b".

[bwilkerson]

I have a proposed fix for this bug. Replace the method with the following:

  private boolean hasRedirectedConstructorCycle(ConstructorElement constructorElement) {
    HashSet<ConstructorElement> visited = new HashSet<ConstructorElement>();
    ConstructorElement next = getNextConstructorInvocation(constructorElement);
    while (next != null) {
      if (visited.contains(next)) {
        return true;
      }
      if (constructorElement.getName().equals(next.getName())) {
        return true;
      }
      visited.add(next);
      next = getNextConstructorInvocation(next);
    }
    return false;
  }

It's difficult for me to run the dartc tests and I'm not certain that this is the right fix, so I'll leave it to you to evaluate it. I believe that it fixes this particular issue, but there appear to be other issues with opening frog. Continuing to investigate the larger issue.

[DartBot]

This comment was originally written by zundel@google.com

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Now that's the kind of bug report I like! (one with a patch in it)
r5447

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Added Fixed label.