Non spatial layers do not have a CRS - API changes only, needs UI change

Refs #19689

src/core/qgsmaplayer.cpp

@@ -738,7 +738,7 @@ void QgsMapLayer::setCrs( const QgsCoordinateReferenceSystem &srs, bool emitSign
 {
   mCRS = srs;
 
-  if ( !mCRS.isValid() )
+  if ( isSpatial() && !mCRS.isValid() )
   {
     mCRS.setValidationHint( tr( "Specify CRS for layer %1" ).arg( name() ) );
     mCRS.validate();

src/core/qgsvectorlayer.cpp

@@ -3010,20 +3010,10 @@ bool QgsVectorLayer::addFeatures( QgsFeatureList &features, Flags )
 
 void QgsVectorLayer::setCoordinateSystem()
 {
-  QgsDebugMsgLevel( QStringLiteral( "Computing Coordinate System" ), 4 );
-
-  if ( isSpatial() )
-  {
-    // get CRS directly from provider
-    setCrs( mDataProvider->crs() );
-  }
-  else
-  {
-    setCrs( QgsCoordinateReferenceSystem( GEO_EPSG_CRS_AUTHID ) );
-  }
+  // if layer is not spatial, it has not CRS!
+  setCrs( isSpatial() ? mDataProvider->crs() : QgsCoordinateReferenceSystem() );
 }
 
-
 QString QgsVectorLayer::displayField() const
 {
   QgsExpression exp( mDisplayExpression );

tests/src/python/test_qgsvectorlayer.py

@@ -336,6 +336,24 @@ def testSetDataSource(self):
         self.assertNotEqual(layer.renderer(), r)
         self.assertEqual(layer.renderer().symbol().type(), QgsSymbol.Line)
 
+    def test_layer_crs(self):
+        """
+        Test that spatial layers have CRS, and non-spatial don't
+        """
+        vl = QgsVectorLayer('Point?crs=epsg:3111&field=pk:integer', 'test', 'memory')
+        self.assertTrue(vl.isSpatial())
+        self.assertTrue(vl.crs().isValid())
+        self.assertEqual(vl.crs().authid(), 'EPSG:3111')
+
+        vl = QgsVectorLayer('None?field=pk:integer', 'test', 'memory')
+        self.assertFalse(vl.isSpatial())
+        self.assertFalse(vl.crs().isValid())
+
+        # even if provider has a crs - we don't respect it for non-spatial layers!
+        vl = QgsVectorLayer('None?crs=epsg:3111field=pk:integer', 'test', 'memory')
+        self.assertFalse(vl.isSpatial())
+        self.assertFalse(vl.crs().isValid())
+
     # ADD FEATURE
 
     def test_AddFeature(self):