Catch exceptions in transform() expression function

(cherry-picked from 2a8333e)

Author: nyalldawson

src/core/qgsexpression.cpp

@@ -50,6 +50,8 @@
 #include "qgsexpressionprivate.h"
 #include "qgsexpressionsorter.h"
 #include "qgscrscache.h"
+#include "qgsmessagelog.h"
+#include "qgscsexception.h"
 
 #if QT_VERSION < 0x050000
 #include <qtextdocument.h>
@@ -3048,8 +3050,16 @@ static QVariant fcnTransformGeometry( const QVariantList& values, const QgsExpre
     return QVariant::fromValue( fGeom );
 
   QgsCoordinateTransform t( s, d );
-  if ( fGeom.transform( t ) == 0 )
-    return QVariant::fromValue( fGeom );
+  try
+  {
+    if ( fGeom.transform( t ) == 0 )
+      return QVariant::fromValue( fGeom );
+  }
+  catch ( QgsCsException &cse )
+  {
+    QgsMessageLog::logMessage( QString( "Transform error caught in transform() function: %1" ).arg( cse.what() ) );
+    return QVariant();
+  }
   return QVariant();
 }
 

tests/src/core/testqgsexpression.cpp

@@ -778,6 +778,7 @@ class TestQgsExpression: public QObject
       QTest::newRow( "distance_to_vertex null" ) << "distance_to_vertex(NULL, 0)" << false << QVariant();
       QTest::newRow( "distance_to_vertex point" ) << "distance_to_vertex(geom_from_wkt('POINT(1 2)'),0)" << false << QVariant( 0.0 );
       QTest::newRow( "distance_to_vertex line" ) << "distance_to_vertex(geometry:=geom_from_wkt('LineString(0 0, 10 0, 10 10)'),vertex:=1)" << false << QVariant( 10.0 );
+      QTest::newRow( "transform invalid" ) << "transform(make_point(0,0),'EPSG:4326','EPSG:28356')" << false << QVariant();
 
       // string functions
       QTest::newRow( "lower" ) << "lower('HeLLo')" << false << QVariant( "hello" );