[QGIS-Developer] cannot import processing algorithm in 3.6

[Nyall Dawson]

On Thu, 21 Mar 2019 at 12:17, Raymond Nijssen <r.nijssen at terglobo.nl> wrote:
>
> Hi Nyall, thanks for your answer.
>
> Somewhere in the middle of a calculation process (not an algorithm) I'd
> like to add a polygon feature to a line layer. I'm using the function to
> turn the polygon into a line geometry.
>
>
>
> I'm using it like this and don't know I figured this out or decided on it:
>
> from processing.algs.qgis import PolygonsToLines
>
> toLines = PolygonsToLines.PolygonsToLines().convertToLines
>
>
> then later on many places in my code:
>
> geom = toLines(geom)
>
>
>
> I remember it took me a while to figure out that second line, but having
> my own short "alias" function toLines() is very convenient. But maybe I
> can create it in another way, holding the processing.run code.

I'd replace this with:

    def toLines(geom):
        return QgsGeometry(geom.get().boundary())

(Using https://qgis.org/pyqgis/master/core/QgsAbstractGeometry.html#qgis.core.QgsAbstractGeometry.boundary
)

Nyall


>
> I will try tomorrow.
>
> One last question, it seems to me like the old code is working again in
> 3.7. Can you confirm that?

Shouldn't be -- maybe you have a leftover .py file here?

>
> Kind regards,
> Raymond
>
>
>
> On 21-03-19 01:34, Nyall Dawson wrote:
> > On Thu, 21 Mar 2019 at 02:40, Raymond Nijssen <r.nijssen at terglobo.nl> wrote:
> >>
> >> The folowing line works for me in 3.4.3 and 3.7 (built today) but not in
> >> 3.6.0
> >>
> >> from processing.algs.qgis import PolygonsToLines
> >
> > It was ported from Python -> c++, so is no longer importable like
> > this. What's your use case for importing direct rather than running
> > via processing.run?
> >
> > Nyall
> >
>
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