Bug 115087 – Web Inspector: WebCore::reportException should not evaluate JavaScript handling exceptions

• Status: NEW
• Component: Web Inspector

[Joseph Pecoraro]

Currently WebCore::reportException can evaluate JavaScript when handling exceptions. The JS evaluation can itself throw an exception if running code in the page.

For example:

    function MyError() {
        this.name = "MyErrorName";
        this.message = "MyErrorMessage";
    }
    MyError.prototype.toString = function() {
        throw "oops";
    }

    function produceError() {
        throw new MyError();
    }

    produceError();

WebCore::reportException call's this toString, and can potentially get values with hooks in valueOf as well. We should avoid running JS that can trigger its own exceptions if possible.

[Geoffrey Garen]

Chris is working on similar bugs in JSC, so reassigning to him.

[Timothy Hatcher]

Moving to the right component.

[Radar WebKit Bug Importer]

<rdar://problem/15796841>

[Joseph Pecoraro]

Oliver had a suggestion on IRC:

    - if the exception object is a builtin Exception/Error object => directly get "message" property
    - if the exception object is a primitive => toString
    - otherwise, send the exception object to the inspector frontend like a console.log (RemoteObject)

I think that is a good idea. This would nicely handle these cases:

    - SyntaxError / ReferenceError
    - throw 1, throw "test", ...
    - throw {a:1,b:2}, throw [1,2,3], throw new MyError()