[QGIS-Developer] How to update change the datasource of already existing layer

[Nyall Dawson]

On Tue, 11 Jun 2019 at 15:06, Ivan Ivanov <suricactus at gmail.com> wrote:
>
> Hello,
>
>
> Can you give me some idea why I'm getting two uids in the layer's source? And also how I can fix this because now the layer just disappears from the map canvas. (all layers are isValid() = True)
>
> oldLayer.source()
> # MultiLineString?crs=EPSG:32737&field=fid:integer(0,0)&uid={6cd1f176-9c05-4d2a-961a-3143a8fa422b}
>
> newLayer = processing.run('save:selectedfeatures', {
>     'INPUT': oldLayer,
>     'OUTPUT': 'memory:newLayer'
> )
>
> oldLayer.setDataSource(newLayer.source(), oldLayer.name(), newLayer.dataProvider().name())
>
> newLayer.source()
> # MultiLineString?crs=EPSG:32737&field=fid:integer(0,0)&uid={d36aff88-4248-4ffb-be2f-2ac1891ac26d}
> oldLayer.source()
>
> # WRONG, I would expect the same as above. Also, the uid is completely new.
> # MultiLineString?crs=EPSG:32737&field=fid:integer(0,0)&uid={d36aff88-4248-4ffb-be2f-2ac1891ac26d}&uid={3422de07-cf38-4249-af55-23c7d9779daf}

Hi Ivan,

Your code seems incomplete and has some syntax errors -- maybe it
wasn't copied correctly? Can you repost please?

Nyall