Bug report #16238: Loading a plugin that adds to the processing plugin does not work correctly - QGIS Application - QGIS Issue Tracking

Bug report #16238

Loading a plugin that adds to the processing plugin does not work correctly

Added by Ari Jolma about 8 years ago. Updated about 7 years ago.

Status:	Closed
Priority:	Normal
Assignee:	Victor Olaya
Category:	Processing/Core
Affected QGIS version:	master	Regression?:	No
Operating System:		Easy fix?:	No
Pull Request or Patch supplied:	No	Resolution:	not reproducable
Crashes QGIS or corrupts data:	No	Copied to github as #:	24148

Description

Loading a plugin that adds to the processing plugin leads to a keyerror:

Traceback (most recent call last):
  File "/home/ajolma/usr/share/qgis/python/plugins/processing/gui/ProcessingToolbox.py", line 320, in addProvider
    providerItem = TreeProviderItem(provider_id, self.algorithmTree, self)
  File "/home/ajolma/usr/share/qgis/python/plugins/processing/gui/ProcessingToolbox.py", line 383, in __init__
    self.populate()
  File "/home/ajolma/usr/share/qgis/python/plugins/processing/gui/ProcessingToolbox.py", line 395, in populate
    provider = algList.algs[self.provider_id]
KeyError: 'perl'

This is probably due to a bug in core/alglist.py, where the provider is added to processing registry before adding it to the algs hash, leading to a chicken-and-egg type of problem.

The bug is not fatal since the plugin gets loaded and once it is activated in the processing options (a deactivate - activate cycle is needed), it is ok.

In addition, I did not get the _loadAlgorithms method of the provider to execute via any other way than through an unload-load-deactivate-activate cycle.

History

#1 Updated by Ari Jolma about 8 years ago

I forgot to mention that the plugin initially loads ok. This bug happens only when one unloads + loads the plugin, which I had to do to invoke the refreshing of the algorithm list.