Be a bit more forgiving and handle raw map layer pointers in

expression values But raise a warning on debug builds that these should be avoided in place of weak pointers
qgis · Feb 7, 2022 · 8cf7f56 · 8cf7f56
1 parent 9139c08
commit 8cf7f56
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diff --git a/src/core/expression/qgsexpressionutils.h b/src/core/expression/qgsexpressionutils.h
@@ -356,6 +356,17 @@ class CORE_EXPORT QgsExpressionUtils
     {
       // First check if we already received a layer pointer
       QgsMapLayer *ml = value.value< QgsWeakMapLayerPointer >().data();
+      if ( !ml )
+      {
+        ml = value.value< QgsMapLayer * >();
+#ifdef QGISDEBUG
+        if ( ml )
+        {
+          qWarning( "Raw map layer pointer stored in expression evaluation, switch to QgsWeakMapLayerPointer instead" );
+        }
+#endif
+      }
+
       QgsProject *project = QgsProject::instance();
 
       // No pointer yet, maybe it's a layer id?

diff --git a/tests/src/core/testqgsexpression.cpp b/tests/src/core/testqgsexpression.cpp
@@ -4246,6 +4246,57 @@ class TestQgsExpression: public QObject
       QCOMPARE( result.toString(), QString( "f2" ) );
     }
 
+    void testExpressionUtilsMapLayerRetrieval()
+    {
+      QgsExpression exp;
+      // NULL value
+      QgsMapLayer *res = QgsExpressionUtils::getMapLayer( QVariant(), &exp );
+      QVERIFY( !res );
+      QVERIFY( !exp.hasEvalError() );
+
+      // value which CANNOT be a map layer
+      res = QgsExpressionUtils::getMapLayer( QVariant( 5 ), &exp );
+      QVERIFY( !res );
+#if 0
+      // TODO probably **should** raise an eval error for this situation?
+      QVERIFY( exp.hasEvalError() );
+#endif
+
+      // with weak map layer pointer
+      exp = QgsExpression();
+      QgsWeakMapLayerPointer weakPointer( mPointsLayer );
+      res = QgsExpressionUtils::getMapLayer( QVariant::fromValue( weakPointer ), &exp );
+      QCOMPARE( res, mPointsLayer );
+      QVERIFY( !exp.hasEvalError() );
+
+      // with raw map layer pointer
+      exp = QgsExpression();
+      res = QgsExpressionUtils::getMapLayer( QVariant::fromValue( mPointsLayer ), &exp );
+      QCOMPARE( res, mPointsLayer );
+      QVERIFY( !exp.hasEvalError() );
+
+      // with layer id
+      exp = QgsExpression();
+      res = QgsExpressionUtils::getMapLayer( mPointsLayer->id(), &exp );
+      QCOMPARE( res, mPointsLayer );
+      QVERIFY( !exp.hasEvalError() );
+
+      // with layer name
+      exp = QgsExpression();
+      res = QgsExpressionUtils::getMapLayer( mPointsLayer->name(), &exp );
+      QCOMPARE( res, mPointsLayer );
+      QVERIFY( !exp.hasEvalError() );
+
+      // with string which is neither id or name
+      exp = QgsExpression();
+      res = QgsExpressionUtils::getMapLayer( QStringLiteral( "xxxA" ), &exp );
+      QVERIFY( !res );
+#if 0
+      // TODO -- probably should flag an error here?
+      QVERIFY( !exp.hasEvalError() );
+#endif
+    }
+
     void test_env()
     {
       QgsExpressionContext context;