DB manager virtual layers: wrong list, layers removed from project

[qgib]

Author Name: Giovanni Manghi (@gioman)
Original Redmine Issue: 16534
Affected QGIS version: master
Redmine category:db_manager

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This has been seen on 2.18.7 and master (QGIS 3) as well. Steps to replicate the issues:

• Load a shapefile
• Open DB Manager > look into the "virtual layers/QGIS layers group", the shapefile loaded in the project is listed
• Browse a PostGIS connection, select a table and preview its geometries
• Select again "virtual layers/QGIS layers group" and click on the refresh button > the previewed layer in now in the virtual layers group(?). This only happens if in the above steps you preview the geometries, does not happen if you preview the table or see the table infos
• Now preview the geometries of the (Postgis) table as visible in the virtual layers group > mouse pointer hourglass pointer starts and never ends
• Click on the (shapefile) layer as visible in the "virtual layers" group
• Click on the (PostGIS) layer as visible in the "virtual layers" group > the shapefile is REMOVED from the project

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Related issue(s): #24385 (duplicates)
Redmine related issue(s): 16476

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[qgib]

Author Name: Giovanni Manghi (@gioman)

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also while doing the above steps I have also seen this (not always):

Traceback (most recent call last):
  File "C:/OSGEO4~1/apps/qgis/./python/plugins\db_manager\layer_preview.py", line 67, in runPrev
    return self._loadTablePreview(item)
  File "C:/OSGEO4~1/apps/qgis/./python/plugins\db_manager\layer_preview.py", line 116, in _loadTablePreview
    if not vl.isValid():
AttributeError: 'NoneType' object has no attribute 'isValid'

[qgib]

Author Name: Luigi Pirelli (@luipir)

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seems that db_manager qgis layer list in Virtual Layer gets layers form shown layers in the QgsMapCanvas instance of the preview table

[qgib]

Author Name: Harrissou Santanna (@DelazJ)

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Is this a duplicate of #24385?

[qgib]

Author Name: Luigi Pirelli (@luipir)

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right Harrissou

[qgib]

Author Name: Giovanni Manghi (@gioman)

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• resolution was changed from to duplicate
• status_id was changed from Open to Closed

[qgib]

Author Name: Jürgen Fischer (@jef-n)

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• duplicates was configured as DB Manager: previewing layers in Virtual layers section remove them from the Layers panel #24385