[Qgis-developer] Undo command crashes QGIS when called from within plugin.

[John Stevenson]

Hi,

I have code within a plugin that I am writing that is similar to:

```
def feature_added(self, fid):
    self.vlayer.beginEditCommand('Update attributes')
    self.vlayer.changeAttributeValue(fid, 2, 17)
    self.vlayer.endEditCommand()
```

It is called in response to a featureAdded signal from the layer.  The command runs and the attributes are updated and the canvas refreshes to show them.  However, when I check the undoStack for the layer, the command is not present.  When I press 'Undo', QGIS has a hard crash.

If I use the QGIS iPython console to access the layer directly through my plugin (e.g. via qgis.utils.plugins['MyPlugin']) and type the equivalent commands directly into the console, everything works as expected, but the changes are not visible until the canvas is manually refreshed.

Is there something else that should / shouldn't be called by the plugin to put the undo command onto the stack?

I'm on QGIS 2.12.0 on Linux Mint 17 (Ubuntu 14.04).

Thanks,
John



John Stevenson
Senior Developer


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