[webkit-dev] WebCore: Exposing exceptions through WebFrameImpl::executeScriptAndReturnValue and ScriptController::executeScript.

[Tom Rathbone]

Sounds like this conversion might be being done in the wrong place, it
doesn't feel like this should be the responsibility of this method
since "undefined" is a valid return value from any JavaScript call.

On Wed, Dec 22, 2010 at 4:41 PM, Yury Semikhatsky <yurys at chromium.org> wrote:
>
>
> On Wed, Dec 22, 2010 at 7:22 PM, Tom Rathbone <tom.rathbone at gmail.com>
> wrote:
>>
>> From my experiments calling executeScriptAndReturnValue "function
>> foo() { } foo();" will also return an empty handle meaning that this
>> can't reliably be used to detect errors.  Is there another way to
>> distinguish non values from errors?
>
> I see, the problem is that 'undefined' value is converted into an empty
> ScriptValue in ScriptController::evaluate:
> http://codesearch.google.com/codesearch/p?hl=en#OAMlx_jo-ck/src/third_party/WebKit/WebCore/bindings/v8/ScriptController.cpp&q=::executeScriptAndReturnValue%5C(&gs=cpp:WebCore::ScriptController::executeScript(const%2520WebCore::ScriptSourceCode%2520&amp;,%2520enum%2520ShouldAllowXSS)@chrome/trunk/src/third_party/WebKit/WebCore/bindings/v8/ScriptController.h%257Cdecl&gsn=executeScript&d=5&l=260
> Not sure what this conversion is used for.
> Yury
>
>
>>
>> On Wed, Dec 22, 2010 at 2:35 PM, Yury Semikhatsky <yurys at chromium.org>
>> wrote:
>> > Hi Tom,
>> > In case of uncaught JS exception returned v8::Handle will always be
>> > empty
>> > (v8::Handle<v8::Value>::IsEmpty() will return true) while in case of
>> > successful
>> > evaluation the result is always non-empty. Also uncaught JS exception
>> > will
>> > be
>> > reported to the console object(see Console.cpp) which will propagate
>> > them
>> > to
>> > InspectorController and ChromeClient.
>> > Thanks,
>> > Yury
>> >
>> > On Wed, Dec 22, 2010 at 12:58 PM, Tom Rathbone <tom.rathbone at gmail.com>
>> > wrote:
>> >>
>> >> Hi Guys,
>> >>
>> >> I was wondering if it would be possible to expose v8 exceptions
>> >> through WebFrameImpl::executeScriptAndReturnValue and
>> >> ScriptController::executeScript, perhaps as an output reference
>> >> argument.
>> >>
>> >> The effected methods would be:
>> >>
>> >> v8::Handle<v8::Value> WebFrameImpl::executeScriptAndReturnValue(const
>> >> WebScriptSource& source)
>> >> ScriptValue ScriptController::executeScript(const ScriptSourceCode&
>> >> sourceCode, ShouldAllowXSS shouldAllowXSS)
>> >> ScriptValue ScriptController::evaluate(const ScriptSourceCode&
>> >> sourceCode, ShouldAllowXSS shouldAllowXSS)
>> >> v8::Local<v8::Value> V8Proxy::evaluate(const ScriptSourceCode& source,
>> >> Node* node)
>> >>
>> >> If I've read the source correctly V8 exceptions are caught in
>> >> V8Proxy::evaluate and swallowed.  This means clients calling
>> >> executeScriptAndReturnValue have no easy way of determining what went
>> >> wrong or of responding to script errors.
>> >>
>> >> Maybe...
>> >>
>> >> v8::Handle<v8::Value> WebFrameImpl::executeScriptAndReturnValue(const
>> >> WebScriptSource& source, bool& exceptionReturned)
>> >>
>> >> If others think these changes are worthwhile then I'll have a go at
>> >> crafting a patch.
>> >>
>> >> Thanks,
>> >>
>> >> Tom.
>> >> _______________________________________________
>> >> webkit-dev mailing list
>> >> webkit-dev at lists.webkit.org
>> >> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
>> >
>> >
>
>