Dart2JS ByteBuffers inconsistence

[DartBot]

This issue was originally filed by [email protected]

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I'm using dart to create some binary file reader in browser. So, i wrote code, that works with dart:typed_data.ByteData, it uses Uint8List as data keeper and ByteData as raw data converter.
The code i wrote perfectly works on Dartium, but when i've tried to execute dart2js compiled code in Chrome 28.0.1500.95 m (Win7 x64), i've meet up some troubles.

What steps will reproduce the problem?
0. Open in

1. We have a fullfilled Uint8List Reader._base;
2. Client code triyng to execute Reader.readInt()
    int readInt(){
       assert(!this.eof);
       ByteBuffer bb = this._base.buffer;
       ByteData bd = new ByteData.view(bb, this._pos, 4);
       assert(bd != null);
       this._seekPos(this._pos+4);
       return bd.getInt32(0, this._endian);
     }
3. In console i get

Uncaught Error: NoSuchMethodError : method not found: 'Object #<ByteBuffer> has no method 'get$buffer''
Receiver: ""
Arguments: []
Stack Trace:
TypeError: Object #<ByteBuffer> has no method 'get$buffer'
    at $.get$buffer$x (http://127.0.0.1:3030/D:/dev/tmp/repos/odc/odc/web/odc.dart.js:73305:39)
    at Reader.readInt$0 (http://127.0.0.1:3030/D:/dev/tmp/repos/odc/odc/web/odc.dart.js:65194:41)
    at Documents_importDocument (http://127.0.0.1:3030/D:/dev/tmp/repos/odc/odc/web/odc.dart.js:63395:12)

[rakudrama]

The VM and dart2js implementations are slightly inconsistent.
See Issue #10136.

I suspect that your program has a small bug but works in the VM because a single object (your buffer/list) implements both interfaces: Uint8List and ByteBuffer.

On dart2js these are always separate types - no browser object implements both interfaces.

My guess is that Reader._base is actually initialized to a ByteBuffer. On the VM this does not matter because it is also a Uint8List.
If you compile dart2js in checked mode you should get an exception at the initialization of '_base'.
Or you could try to print the type: print(this._base.buffer.runtimeType);

Because the VM Uint8List is also a ByteBuffer, running on the VM did not help you find this bug.

If my guess is correct I would like to close this bug as a duplicate of Issue #10136.

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Added Triaged label.

[DartBot]

This comment was originally written by [email protected]

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ОК, I see now.

Really, it was my mistake, the HttpRequest.responce's type was unexpected and it was not typechecked in preconditions of Reader's constructor.

Thanks for quick answer!

[anders-sandholm]

Added Duplicate label.
Marked as being merged into #10136.