Re: [Jython-dev] Support for sys._current_frames

[Stefan R. <Ste...@gm...>]

> Your elements array should be twice as long, I think?
Obviously it should ;)

Agreed on all points. I just tested the implementation and observed that
an entry in globalThreadStates yields a null-PyFrame. How should we deal
with that?

a) Is it a bug and we should investigate how it can be null and solve it?
b) set the frame to None in result of _current_frames
c) skip such elements and let _current_frames only return a reduced dict?

@Fabio regarding b), would PyDev be robust against None-values here?

Despite this, the result looks rather much like in CPython.


> Gesendet: Mittwoch, 29. März 2017 um 22:04 Uhr
> Von: "Jeff Allen" <ja...@fa...>
> An: jyt...@li...
> Betreff: Re: [Jython-dev] Support for sys._current_frames
>
> This seems to be a faithful equivalent to the CPython implementation. 
> That is wrapped in a synchronisation construct, but globalThreadStates 
> is of a thread-safe class, I see. However, as the number of threads 
> might change between the call to size() and the call to toArray(), I 
> think it would be better to let toArray() always allocate the array 
> (i.e. give it a zero-length prototype).
> 
> Your elements array should be twice as long, I think?
> 
> The way we manage ThreadState and interpreters leaves me uneasy, but 
> that's not a criticism against this proposal, except for the risk of 
> change when the penny finally drops.
> 
> Oh, and thanks to Fabio for continuing to support Jython in PyDev.
> 
> Jeff Allen
> 
> On 29/03/2017 17:30, Stefan Richthofer wrote:
> > I suggest this could be implemented in ThreadStateMapping like this:
> > (on top of that an implementation in PySystemState is straight forward)
> >     public static PyObject _current_frames() {
> >         @SuppressWarnings("unchecked")
> >         Map.Entry<Thread, ThreadState>[] entries = new 
> > Map.Entry[globalThreadStates.size()];
> >         entries = globalThreadStates.entrySet().toArray(entries);
> >         PyObject elements[] = new PyObject[entries.length];
> >         int pos = 0;
> >         for (Map.Entry<Thread, ThreadState> entry: entries) {
> >             elements[pos++] = Py.newInteger(entry.getKey().getId());
> >             elements[pos++] = entry.getValue().frame;
> >         }
> >         return new PyDictionary(elements);
> >     }
> > Opinions?
> > -Stefan
> > *Gesendet:* Mittwoch, 29. März 2017 um 17:30 Uhr
> > *Von:* "Fabio Zadrozny" <fa...@gm...>
> > *An:* "Jython Developers" <jyt...@li...>
> > *Betreff:* [Jython-dev] Support for sys._current_frames
> > Hi Jython devs,
> > I've just updated the PyDev debugger to drop support for older Python 
> > versions and it seems I ended up breaking debugging in the current 
> > Jython version because of it...
> > The issue is that PyDev now requires sys._current_frames to be 
> > implemented by the interpreter (available since Python 2.5), but it 
> > seems this is not available for Jython -- this is needed so that the 
> > debugger can be faster (i.e.: it runs with untraced frames until some 
> > breakpoint is actually added -- at that point it gets the current 
> > frames and sets the tracing in them).
> > So, I'd like to check how feasible it'd be to have this support in Jython.
> > Thanks,
> > Fabio
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