[QGIS-Developer] free variable 'self' referenced before assignment in enclosing scope

Raymond Nijssen r.nijssen at terglobo.nl
Thu Jan 31 00:02:51 PST 2019

Hi Bjorn,

What do you expect this


would result in? It doesn't look like python to me but I might be 
missing something.

What does the variable self.Branches contain?

"self" Refers to your Branches_Nodes class itself.

(By the way, it is a good habit to start variable names with a lower 
case character.)


On 30-01-19 17:40, Bjørn Burr Nyberg wrote:
> Dear QGIS community,
> In the spirit of open-source I am trying to convert a set of scripts that ive designed in ArcMap to QGIS 3.x. I hope that this will enable a broader community of individuals to use the workflows ive designed. The original scripts can be found at https://github.com/BjornNyberg/NetworkGT/tree/master/Scripts
> My problem is that in my first attempt to convert the scripts, QGIS either crashes or gives the following error.
> 2019-01-30T16:51:27     WARNING    Traceback (most recent call last):
>                File "C:/PROGRA~1/QGIS3~1.4/apps/qgis/./python/plugins\processing\gui\AlgorithmDialog.py", line 238, in on_complete
>                self.feedback.pushInfo(self.tr('Execution completed in {0:0.2f} seconds').format(time.time() - start_time))
>               NameError: free variable 'self' referenced before assignment in enclosing scope
> I have established that this error occurs at the very end of the script when calling ' return {self.Branches:dest_id,self.Nodes:dest_id2}'. I do not believe that I have explicitly defined self  anywhere in the processAlgorithm function itself. The algorithms themselves work as intended and the shapefiles are created before the program crashes.
> I am not a programmer by trait so I'm not entirely sure how to problem solve this error and any help would be most appreciated. I can also provide a test dataset if that is helpful.
> Cheers,
> Bjorn
> -----------------------------
> Postdoctoral Fellow
> Department of Earth Science, University of Bergen
> PO Box 7803, 5020, Bergen, Norway
> +47 485 024 08
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