Review Request 110027: kjs: Don't crash if code in with-statement causes a "pre"-exception

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(Updated April 18, 2013, 1:10 p.m.)


Status
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This change has been marked as submitted.


Review request for kdelibs.


Description
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For js code like:
with({}) { with({}) { with({}) { import x.x; }  }  }

the import statement can cause an exception, the import-exception is generated (but not fired) before it executes the other code.
The With-statement has 2 operations to push and pop the new scope it should be used with.
As the pre-generated Exception is already present, PushScope checks that and does not Push a new Scope.
But PopScope does not check that, and tries to pop, which leads us to a crash.
The Scope should be cleared by the Exceptionhandler on exception case, and PopScope should do nothing.

NOTE: I must admit I am unsure if this is the best solution, a review by a experienced kjs developer would be super helpful


This addresses bugs 311512 and 311513.
    http://bugs.kde.org/show_bug.cgi?id=311512
    http://bugs.kde.org/show_bug.cgi?id=311513


Diffs
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  kjs/bytecode/codes.def 59fea6c 

Diff: http://git.reviewboard.kde.org/r/110027/diff/


Testing
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Fixes the crash cases in the bugreport:

{with({}) { import window.x; } M:do {with(NaN = y)NaN = 1.3; } while(0); }
try { with({}) /*TODE2*/if(window) { if (V) {continue ;; }} else import set.x; } finally { x.__proto__ = x; }
try { with({}) { import x.*; }  } finally { return (x); }
with({}) { with({}) { with({}) { import x.x; }  }  }


and still keeps normal cases working like for example:
with({a:2}) { print(a); }
with(Math) { a= PI *2; print(a); }


Thanks,

Bernd Buschinski

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