Minimal repro: https://github.com/kevmoo/dart_sdk_9283

Last commit is with minify.
Previous commit is without minify. No issue.

This is a regression.

Attachment:
[Screen Shot 2013-03-19 at 1.54.13 PM.png](https://storage.googleapis.com/google-code-attachments/dart/issue-9283/comment-1/Screen Shot 2013-03-19 at 1.54.13 PM.png) (36.30 KB)

Added Triaged label.

I will investigate.

Set owner to @vsmenon.

Changed the title to: "dart2js: minified breaks JS-interop [REGRESSION]".

Dart SDK version 0.4.2.5_r20193

It's an NSM issue. If I run the code below (using the editor / wizard web app as a template), I should get:

"Called HelloWorld"

With dart2js --minify, I get:

"Called Df".

Kevin: are you saying it used to work with --minify?

import 'dart:html';

class A {
  noSuchMethod(InvocationMirror invocation) {
    String member = invocation.memberName;
    query("#sample_text_id")
    ..text = "Called $member";
  }
}

void main() {
  A a = new A();
  a.HelloWorld();
}

cc @kasperl.
cc @peter-ahe-google.
cc @rakudrama.
Removed the owner.
Changed the title to: "dart2js: minified does not work with noSuchMethod.".

I've used minify for a while with no issues. This seems a regression from one of the last integration builds.

Thanks, I also verified that my mini-test above works correctly on Dart SDK version 0.4.1.0_r19425.

Does the code work with dart2dart minification? Did it ever? I think the answer to both questions is "no".

The new and much more compact way we deal with NSM is according to the specification and as far as I know it's perfectly valid to construct the InvocationMirror object using the minified names.

We have talked about a way of opt'ing in to carrying the mapping from minified to unminified names around. In a way, this issue is really a feature request for that.

cc @ErikCorryGoogle.
cc @gbracha.

Yes, it did indeed stop working on this CL (r20005):

    dart2js: Create noSuchMethod handlers at runtime to reduce overhead.
    
    This reduces the overhead for using noSuchMethod from over 10% to around 2%.
    Following this change the original source names are not present when
    minifying. This means you get the minified name in the methodName property
    on InvocationMirror objects.
    
    R=ngeoffray@google.com
    BUG=
    
    Review URL: https://codereview.chromium.org//12499005

FWIW, the spec does say that calling memberName on the InvocationMirror gives a string that matches the true name of the method (with an = at the end if it is a setter). Minification breaks that. You can argue that the user asked for a source transformation that has this effect, but this is highly debatable. What if the user tests to see if the names match a certain pattern (like, starting with _ to see if it was a private method).

At the very least, there needs to be an opt-out mechanism, or an API that lets you convert source names to minified names.

Gilad, can you please clarify the correct behavior?

I see no mention in the spec of minification. It does say:

"The result of looking up a method m in object o with respect to library L is.... a new instance im of the predefined class InvocationMirror is created, such that ... im.memberName evaluates to ‘m’."

which suggests to me that im.memberName should have the original method name.

Gilad, sorry for the crossed streams, and thanks for answering my question before I asked it. :-)

Kasper, how should we proceed on this?

Kevin,

If you get a chance, can you try replacing:

  js.context.pushAnalytics(...);

with this:

  js.context'pushAnalytics';

in your code? The latter should not trigger NSM.

No dice.

See last few commits here for changes: https://github.com/dart-lang/pop-pop-win/commits/master

Attachment:
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A workaround is illustrated in https://code.google.com/p/dart/codesearch#dart/trunk/dart/tests/language/no_such_method_test.dart

If there are a few names you want to get the real name from you can use the getName technique from this test to get them.