[Qgis-developer] QGIS crash removing group containing rasters

[Luca Congedo]

OK, I see.
Thank you very much.

Cheers,
Luca

2016-09-03 19:30 GMT+02:00 Alessandro Pasotti <apasotti at gmail.com>:

>
> On Sat, Sep 3, 2016 at 5:09 PM, Luca Congedo <semiautomatic.blogger at gmail.
> com> wrote:
>
>> I think I found the cause of the issue when trying to remove a layer that
>> was already removed.
>> To reproduce in Python console:
>> # add raster
>> l1 = qgis.utils.iface.addRasterLayer("C:\Users\a\Desktop\LC81900312013105LGN01_B2.tif",
>> "raster1")
>>
>> remove manually the raster
>>
>> # try to remove the raster
>> QgsMapLayerRegistry.instance().removeMapLayer(l1.id())
>>
>> QGIS crashes
>>
>> Cheers,
>> Luca
>>
>>
>>
>
> Hi, I believe that this is not something we can fix easily: removing the
> layer from the map registry deletes the layer removing the object from
> memory but the python variable still points to an object that was deleted,
> of course it crashes.
>
> There are many other similar ways you can make QGIS crash, this is due to
> the nature of Python - C++ bindings and there is not much we can do, the
> Python programmers should take care to avoid such potentially dangerous
> situations.
>
> You might want to use the sip API directly if you want to check for
> deleted objects:
> http://pyqt.sourceforge.net/Docs/sip4/python_api.html
>
> Hope this helps.
>
> Cheers
>
>
>
>> 2016-09-03 11:57 GMT+02:00 Luca Congedo <semiautomatic.blogger at gmail.com>
>> :
>>
>>> Hi Matthias,
>>>
>>> yes, it happens in Windows when removing the group manually (it seems
>>> that Linux is not affected).
>>> I had a button in the plugin for removing the temporary rasters which I
>>> have now disabled in a plugin update.
>>>
>>> Luca
>>>
>>>
>>> 2016-09-03 11:53 GMT+02:00 Matthias Kuhn <matthias at opengis.ch>:
>>>
>>>> Hi Luca,
>>>>
>>>> does it also happen when you do the same process manually?
>>>>
>>>> Matthias
>>>>
>>>> On 09/03/2016 11:43 AM, Luca Congedo wrote:
>>>> > Hello everybody,
>>>> >
>>>> > removing a group (created by the Semi-Automatic Classification Plugin)
>>>> > containing rasters from QGIS layers causes a crash.
>>>> > To reproduce, if you create 2 or more classification previews with the
>>>> > Semi-Automatic Classification Plugin and then remove the group
>>>> > 'Class_temp_group' from the layers.
>>>> > Is there anything I can do at the plugin level, or should I open a
>>>> ticket?
>>>> >
>>>> > Thank you,
>>>> > Luca
>>>> >
>>>> >
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>>>
>>
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>
>
>
> --
> Alessandro Pasotti
> w3:   www.itopen.it
>
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