QGIS » QGIS Application

With QGIS LTR 3.4.5-1 on Windows 7 64 bit, the "Select Extent" (ExtentSelectionPane.py) dialog is not working in processing algorithms which have an extent as input.

For example, in the "Random points in extent" (qgis:randompointsinextent) algorithm dialog window, clicking on the "Input extent" parameter ellipsis button and then on the "Use Layer Extent..." menu item, the following error is displayed in the QGIS Message bar

Python error: An error has occurred while executing Python code: See message log (Python Error) for more details.

and the following warning is written in the Python Error message log

WARNING    Traceback (most recent call last):
              File "C:/PROGRA~1/QGIS3~1.4/apps/qgis-ltr/./python/plugins\processing\gui\ExtentSelectionPanel.py", line 167, in useLayerExtent
              dlg = LayerSelectionDialog(self)
              File "C:/PROGRA~1/QGIS3~1.4/apps/qgis-ltr/./python/plugins\processing\gui\ExtentSelectionPanel.py", line 72, in __init__
              QgsMapLayerProxyModel.HasGeometry | QgsMapLayerProxyModel.RasterLayer | QgsMapLayerProxyModel.MeshLayer)
             AttributeError: type object 'QgsMapLayerProxyModel' has no attribute 'MeshLayer'

so it's impossible to select a layer extent as input extent of the processing algorithm.

Other processing algorithms affected are:

"Regular points" qgis:regularpoints
"Create constant raster layer" qgis:createconstantrasterlayer
"Create grid" qgis:creategrid
"Raster calculator" qgis:rastercalculator
"Clip vector by extent" gdal:clipvectorbyextent
"Clip raster by extent" gdal:cliprasterbyextent
...

Probably the bug was introduced at 06ee1326 backporting PR 9038 to 3.4: 'QgsMapLayerProxyModel' has no attribute 'MeshLayer' in 3.4 API but only since 3.6 (https://qgis.org/api/classQgsMapLayerProxyModel.html).