QtScript considered dangerous

[Aleix Pol]

On Mon, Aug 13, 2012 at 3:44 PM, Milian Wolff <mail at milianw.de> wrote:
> Hey all,
>
> I just wanted to notify you that a fix to this notorious QtScript bug was
> released in time for 4.8.3. For now, I can retract my statement that QtScript
> should be considered dangerous :) So Kate can stick to QtScript and I don't
> have to port it to KJS at the upcoming hack sprint!
>
> See also:
> https://bugreports.qt-project.org/browse/QTBUG-23871
> https://bugs.kde.org/show_bug.cgi?id=297661
>
> The patch can be found here:
> https://codereview.qt-project.org/#change,32359
>
> Many thanks to Kent Hansen for fixing this bug!
>
> Cheers
>
> On Thursday 24 May 2012 10:59:21 Dominik Haumann wrote:
>> Hi Milian,
>>
>> CC: kde-core-devel, as this is really a tough issue...
>>
>> there are other applications like Kile that heavily use QtScript for
>> scripting as well, so porting away KatePart from QtScript may solve the
>> issue for KDevelop, the real problem lies (as you say) within QtScript, not
>> Kate. The reason for why we use QtScript are:
>> - QtScript is very (!) easy to use
>> - QtScript is maintained (at least at that time?)
>> - really good documentation
>>
>> There are other arguments, why we finally ended up with QtScript:
>> - kjs is pretty much undocumented, meaning that it's not immediately clear
>>   e.g. how to export custom classes and so on.
>> - at the time we dropped kjs, it wasn't clear whether it's going to be
>>   maintained and improved (the speed in QtScript was much better). At that
>>   time, there were even lots of people shouting "drop khtml" etc...
>>
>> Initially, KatePart even used kjs and the code was a lot more complex to get
>> the same thing as we have now with QtScript. That alone is a strong
>> argument for using QtScript.
>>
>> With regard to Kate, we are about to export our js-API so that other classes
>> can use our returned QScriptValues. Once this is the case, we cannot go
>> back due to BIC reasons. So this is a tough issue... We can go back to
>> using kjs again, of course, but then, I still have lots of questions [1]
>> :-)
>>
>> What about other solutions: Reduce memory consumption in KDevelop?
>> Another question is: Maybe we'll have similar/other issues with kjs? ;)
>>
>> Greetings,
>> Dominik
>>
>> [1] http://kate-editor.org/2012/05/12/rfc-exporting-javascript-api/
>>
>> On Wednesday, May 23, 2012 22:08:08 Milian Wolff wrote:
>> > Hey all,
>> >
>> > I have a sad discussion to start it seems:
>> >
>> > We have port Kate away from QtScript.
>> >
>> > See also:
>> >
>> > https://bugs.kde.org/show_bug.cgi?id=297661
>> > https://bugreports.qt-project.org/browse/QTBUG-23871
>> >
>> > This is the number one reason for crashes I get recently, and makes
>> > KDevelop unusable. Apparently Kate usually doesn't that issue since it
>> > doesn't use as much memory as KDevelop (see the Qt bugreport).
>> >
>> > The bug report is open since ~4 months without any feedback from any Qt
>> > developers. Today I had a chat with a few Nokia Qt developers at LinuxTag
>> > and they said they will probably not spent the considerable amount of time
>> > in updating the archaic jsc checkout used in QtScript. Apparently, Digia
>> > is supposed to handle Qt 4.x issues like these and seriously, they don't
>> > really do anything as long as a commercial customer of them requires a bug
>> > to be fixed...
>> >
>> > Since this issue renders KDevelop unusable (crashes with stack corruption
>> > or assertion every few keypresses that issue a run of the indenter script)
>> > I really think we should look for alternatives.
>> >
>> > So - what are the reasons that Kate uses QtScript instead of KJS? I hope
>> > that we can easily port our existing code to KJS without a too high
>> > performance impact, something I'll measure of course. But are there other
>> > reasons beside performance?
>> >
>> > /me who is angry at Digia/Nokia/Qt for not fixing this mess
> --
> Milian Wolff
> mail at milianw.de
> http://milianw.de

That is wonderful, milian :).

Thanks a lot for looking into this! I was going crazy!!

Now, do we have an ETA for 4.8.3? :D

Aleix