Better method to ensure memory layers always have unique sources

src/core/providers/memory/qgsmemoryproviderutils.cpp

@@ -65,8 +65,6 @@ QgsVectorLayer *QgsMemoryProviderUtils::createMemoryLayer( const QString &name,
   {
     parts << QStringLiteral( "field=%1:%2" ).arg( field.name(), memoryLayerFieldType( field.type() ) );
   }
-  // required so that source differs between memory layers
-  parts << QStringLiteral( "uid=%1" ).arg( QUuid::createUuid().toString() );
 
   QString uri = geomType + '?' + parts.join( '&' );
 

src/core/qgsvectorlayer.cpp

@@ -1465,6 +1465,11 @@ bool QgsVectorLayer::setDataProvider( QString const &provider )
     if ( mDataSource.right( 10 ) == QLatin1String( "|layerid=0" ) )
       mDataSource.chop( 10 );
   }
+  else if ( provider == QStringLiteral( "memory" ) )
+  {
+    // required so that source differs between memory layers
+    mDataSource = mDataSource + QStringLiteral( "&uid=%1" ).arg( QUuid::createUuid().toString() );
+  }
 
   connect( mDataProvider, &QgsVectorDataProvider::dataChanged, this, &QgsVectorLayer::dataChanged );
   connect( mDataProvider, &QgsVectorDataProvider::dataChanged, this, &QgsVectorLayer::removeSelection );

tests/src/python/test_provider_memory.py

@@ -338,6 +338,15 @@ def testRenameAttributes(self):
         self.assertEqual(fet.fields()[1].name(), 'mapinfo_is_the_stone_age')
         self.assertEqual(fet.fields()[2].name(), 'super_size')
 
+    def testUniqueSource(self):
+        """
+        Similar memory layers should have unique source - some code checks layer source to identify
+        matching layers
+        """
+        layer = QgsVectorLayer("Point", "test", "memory")
+        layer2 = QgsVectorLayer("Point", "test2", "memory")
+        self.assertNotEqual(layer.source(), layer2.source())
+
     def testCreateMemoryLayer(self):
         """
         Test QgsMemoryProviderUtils.createMemoryLayer()