Fix broken handle bad layers dialog

Partially revert af0bae6 and ea2cc36

Fixes #20265

Author: nyalldawson

src/providers/gdal/qgsgdalprovider.cpp

@@ -1991,6 +1991,10 @@ QStringList QgsGdalProvider::subLayers() const
   return mSubLayers;
 }
 
+QGISEXTERN int dataCapabilities()
+{
+  return QgsDataProvider::File | QgsDataProvider::Dir | QgsDataProvider::Net;
+}
 
 QGISEXTERN QVariantMap decodeUri( const QString &uri )
 {

src/providers/ogr/qgsogrprovider.cpp

@@ -3397,6 +3397,11 @@ QGISEXTERN bool createEmptyDataSource( const QString &uri,
   return true;
 }
 
+QGISEXTERN int dataCapabilities()
+{
+  return  QgsDataProvider::File | QgsDataProvider::Dir;
+}
+
 QGISEXTERN QList< QgsDataItemProvider * > *dataItemProviders()
 {
   QList< QgsDataItemProvider * > *providers = new QList< QgsDataItemProvider * >();

tests/src/python/CMakeLists.txt

@@ -62,6 +62,7 @@ ADD_PYTHON_TEST(PyQgsFilterLineEdit test_qgsfilterlineedit.py)
 ADD_PYTHON_TEST(PyQgsFloatingWidget test_qgsfloatingwidget.py)
 ADD_PYTHON_TEST(PyQgsFontButton test_qgsfontbutton.py)
 ADD_PYTHON_TEST(PyQgsFontUtils test_qgsfontutils.py)
+ADD_PYTHON_TEST(PyQgsGdalProvider test_provider_gdal.py)
 ADD_PYTHON_TEST(PyQgsGeoNodeConnection test_qgsgeonodeconnection.py)
 ADD_PYTHON_TEST(PyQgsGeometryAvoidIntersections test_qgsgeometry_avoid_intersections.py)
 ADD_PYTHON_TEST(PyQgsGeometryGeneratorSymbolLayer test_qgsgeometrygeneratorsymbollayer.py)

tests/src/python/test_provider_gdal.py

@@ -0,0 +1,34 @@
+# -*- coding: utf-8 -*-
+"""Generic Unit tests for the GDAL provider.
+
+.. note:: This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+"""
+__author__ = 'Nyall Dawson'
+__date__ = '2018-30-10'
+__copyright__ = 'Copyright 2018, Nyall Dawson'
+# This will get replaced with a git SHA1 when you do a git archive
+__revision__ = '$Format:%H$'
+
+from qgis.core import (QgsProviderRegistry,
+                       QgsDataProvider)
+from qgis.testing import start_app, unittest
+
+from utilities import unitTestDataPath
+
+start_app()
+TEST_DATA_DIR = unitTestDataPath()
+
+
+class PyQgsGdalProvider(unittest.TestCase):
+
+    def testCapabilities(self):
+        self.assertTrue(QgsProviderRegistry.instance().providerCapabilities("gdal") & QgsDataProvider.File)
+        self.assertTrue(QgsProviderRegistry.instance().providerCapabilities("gdal") & QgsDataProvider.Dir)
+        self.assertTrue(QgsProviderRegistry.instance().providerCapabilities("gdal") & QgsDataProvider.Net)
+
+
+if __name__ == '__main__':
+    unittest.main()

tests/src/python/test_provider_ogr.py

@@ -21,6 +21,7 @@
 from qgis.PyQt.QtCore import QVariant
 from qgis.core import (QgsApplication,
                        QgsRectangle,
+                       QgsProviderRegistry,
                        QgsFeature, QgsFeatureRequest, QgsField, QgsSettings, QgsDataProvider,
                        QgsVectorDataProvider, QgsVectorLayer, QgsWkbTypes, QgsNetworkAccessManager)
 from qgis.testing import start_app, unittest
@@ -72,6 +73,10 @@ def tearDownClass(cls):
         for dirname in cls.dirs_to_cleanup:
             shutil.rmtree(dirname, True)
 
+    def testCapabilities(self):
+        self.assertTrue(QgsProviderRegistry.instance().providerCapabilities("ogr") & QgsDataProvider.File)
+        self.assertTrue(QgsProviderRegistry.instance().providerCapabilities("ogr") & QgsDataProvider.Dir)
+
     def testUpdateMode(self):
 
         vl = QgsVectorLayer('{}|layerid=0'.format(self.datasource), 'test', 'ogr')