69724 - nested functions do not have access to variables defined in their parent function

Status: VERIFIED WORKSFORME

(Core :: JavaScript Engine, defect)

Description

[Robert Ginda]

Here is most of the text from an email I got from Steve Newman,
[e-mail]:

...nested functions do not seem to have access
to variables
defined in their parent function, at least in some cases.
Here is a
test case that reproduces the bug:

    function test()
    {
       var param = 5;
       // var foo = test.__call__;

       (function() {alert(param*param);}) ();
    }

    test();

When I execute this script, I get an undefined-identifier
error
for the use of "param" in the anonymous function.  However,
if I
enable the declaration of "var foo" (by removing the comment
slashes),
the code executes properly.

As far as I can tell, the problem is that in the code for
"case JSOP_ANONFUNOBJ:" in jsinterp.c, the inner function's
parent
chain is set to fp->varobj, but fp->varobj is null.
Referencing
test.__call__ causes js_GetCallObject to be called, which
has the
side effect of filling in fp->varobj with the call object
for the
test() function, and so the ANONFUNOBJ code then sets up the
parent
chain correctly.

Comment 1

[Brendan Eich [:brendan]]

This like so worksforme, and works even better with the brendan/shaver patch in
bug 65308.  Unless someone removed the logic to set JSFUN_HEAVYWEIGHT for the
outer function, I don't see how it could have broken.  I also believe (hope!)
that cases like this are covered by our testsuite.

What version of the engine is Steve using?

/be

Comment 2

[Phil Schwartau]

Verifying WORKSFORME on WinNT. Steve's testcase and variations that I've 
tried seem to work just fine. I will add all this to the JS test suite -