Fix reverse expression function doesn't handle multicurve geometries

src/core/expression/qgsexpressionfunction.cpp

@@ -2662,12 +2662,33 @@ static QVariant fcnReverse( const QVariantList &values, const QgsExpressionConte
   if ( fGeom.isNull() )
     return QVariant();
 
-  const QgsCurve *curve = qgsgeometry_cast<const QgsCurve * >( fGeom.constGet() );
-  if ( !curve )
-    return QVariant();
+  QVariant result;
+  if ( !fGeom.isMultipart() )
+  {
+    const QgsCurve *curve = qgsgeometry_cast<const QgsCurve * >( fGeom.constGet() );
+    if ( !curve )
+      return QVariant();
 
-  QgsCurve *reversed = curve->reversed();
-  QVariant result = reversed ? QVariant::fromValue( QgsGeometry( reversed ) ) : QVariant();
+    QgsCurve *reversed = curve->reversed();
+    result = reversed ? QVariant::fromValue( QgsGeometry( reversed ) ) : QVariant();
+  }
+  else
+  {
+    const QgsGeometryCollection *collection = qgsgeometry_cast< const QgsGeometryCollection *>( fGeom.constGet() );
+    std::unique_ptr< QgsGeometryCollection > reversed( collection->createEmptyWithSameType() );
+    for ( int i = 0; i < collection->numGeometries(); ++i )
+    {
+      if ( const QgsCurve *curve = qgsgeometry_cast<const QgsCurve * >( collection->geometryN( i ) ) )
+      {
+        reversed->addGeometry( curve->reversed() );
+      }
+      else
+      {
+        reversed->addGeometry( collection->geometryN( i )->clone() );
+      }
+    }
+    result = reversed ? QVariant::fromValue( QgsGeometry( std::move( reversed ) ) ) : QVariant();
+  }
   return result;
 }
 

tests/src/core/testqgsexpression.cpp

@@ -851,6 +851,7 @@ class TestQgsExpression: public QObject
       QTest::newRow( "reverse point" ) << "reverse(geom_from_wkt('POINT(1 2)'))" << false << QVariant();
       QTest::newRow( "reverse polygon" ) << "reverse(geom_from_wkt('POLYGON((-1 -1, 4 0, 4 2, 0 2, -1 -1))'))" << false << QVariant();
       QTest::newRow( "reverse line" ) << "geom_to_wkt(reverse(geom_from_wkt('LINESTRING(0 0, 1 1, 2 2)')))" << false << QVariant( "LineString (2 2, 1 1, 0 0)" );
+      QTest::newRow( "reverse multiline" ) << "geom_to_wkt(reverse(geom_from_wkt('MULTILINESTRING((0 0, 1 1, 2 2),(10 10, 11 11, 12 12))')))" << false << QVariant( "MultiLineString ((2 2, 1 1, 0 0),(12 12, 11 11, 10 10))" );
       QTest::newRow( "exterior_ring not geom" ) << "exterior_ring('g')" << true << QVariant();
       QTest::newRow( "exterior_ring null" ) << "exterior_ring(NULL)" << false << QVariant();
       QTest::newRow( "exterior_ring point" ) << "exterior_ring(geom_from_wkt('POINT(1 2)'))" << false << QVariant();