706719 - [ASC BUG] Asc misinterprets default <null> value as "null" string value [BREAKS FLASH PLAYER]

Status: VERIFIED FIXED

(Tamarin Graveyard :: Tools, defect, P1)

Description

[Virgil Palanciuc]

The reason Flash Player failed turns out to be ASC.

Take the following example:

===================
class MyClass {
   public function MyClass(a:String=null) 
   {
       var b:Object = a; 
       trace(b==null);
       trace(b=="null");
   }
}

var a:MyClass= new MyClass();
===================
The expected result is "true false" but it prints "false true". It's not at all obvious why because not even abcdump prints the default argument values - but the reason is in ASC putting a wrong default argument in the "MyClass" constructor.

Comment 1

[Lars T Hansen]

Verified: The default argument is incorrect, it is a string (kind=1), but the value should be null (kind=12).  The bug is probably in or around checkDefaultValue in ConstantEvaluator.java, because this function performs some conversion on method default values.

Comment 2

[Lars T Hansen]

Verified^2, simple fix in checkDefaultValue.

Comment 3

[Lars T Hansen]

I consider this fixed, testing is ongoing though.

Comment 4

[Brent Baker]

changeset:   7074:9a3bea55768d
tag:         tip
user:        Brent Baker <[e-mail]>
date:        Tue Dec 13 10:16:57 2011 -0500
files:       test/acceptance/as3/asc/namespace-parameter-null-default.as test/acceptance/as3/asc/string-parameter-default-null.as
description:
Bug 706719: add test media using a String parameter with a default value as null
Bug 706402: add test media using a Namespace parameter with a default value as null

Comment 5

[Tamarin Bot]

changeset: 7108:82c66e1103a5
user:      Brent Baker <[e-mail]>
summary:   Bug 706719: fix issues around quotes in the TITLE, I added this after I tested the compilation and didn't notice that the text had a double quote in it.

http://hg.mozilla.org/tamarin-redux/rev/82c66e1103a5