Memory layers clone: use updated source

Fixes #34134

src/core/qgsvectorlayer.cpp

@@ -221,11 +221,20 @@ QgsVectorLayer::~QgsVectorLayer()
 QgsVectorLayer *QgsVectorLayer::clone() const
 {
   QgsVectorLayer::LayerOptions options;
+  // We get the data source string from the provider when
+  // possible because some providers may have changed it
+  // directly (memory provider does that).
+  QString dataSource;
   if ( mDataProvider )
   {
+    dataSource = mDataProvider->dataSourceUri();
     options.transformContext = mDataProvider->transformContext();
   }
-  QgsVectorLayer *layer = new QgsVectorLayer( source(), name(), mProviderKey, options );
+  else
+  {
+    dataSource = source();
+  }
+  QgsVectorLayer *layer = new QgsVectorLayer( dataSource, name(), mProviderKey, options );
   if ( mDataProvider && layer->dataProvider() )
   {
     layer->dataProvider()->handlePostCloneOperations( mDataProvider );

tests/src/python/test_provider_memory.py

@@ -10,6 +10,7 @@
 __date__ = '2015-04-23'
 __copyright__ = 'Copyright 2015, The QGIS Project'
 
+from urllib.parse import parse_qs
 
 from qgis.core import (
     QgsField,
@@ -652,6 +653,24 @@ def testSpatialIndex(self):
         vl.dataProvider().createSpatialIndex()
         self.assertEqual(vl.hasSpatialIndex(), QgsFeatureSource.SpatialIndexPresent)
 
+    def testClone(self):
+        """Test that a cloned layer has a single new id and
+        the same fields as the source layer"""
+
+        vl = QgsVectorLayer(
+            'Point?crs=epsg:4326',
+            'test', 'memory')
+        self.assertTrue(vl.isValid)
+        dp = vl.dataProvider()
+        self.assertTrue(dp.addAttributes([QgsField("name", QVariant.String),
+                                          QgsField("age", QVariant.Int),
+                                          QgsField("size", QVariant.Double)]))
+        vl2 = vl.clone()
+        self.assertTrue('memory?geometry=Point&crs=EPSG:4326&field=name:(0,0)&field=age:(0,0)&field=size:(0,0)' in vl2.publicSource())
+        self.assertEqual(len(parse_qs(vl.publicSource())['uid']), 1)
+        self.assertEqual(len(parse_qs(vl2.publicSource())['uid']), 1)
+        self.assertNotEqual(parse_qs(vl2.publicSource())['uid'][0], parse_qs(vl.publicSource())['uid'][0])
+
 
 class TestPyQgsMemoryProviderIndexed(unittest.TestCase, ProviderTestCase):