[processing] Fix incorrect OGR warnings when loading raster layer results

python/core/auto_generated/processing/qgsprocessingcontext.sip.in

@@ -126,7 +126,7 @@ Details for layers to load into projects.
 %End
       public:
 
-        LayerDetails( const QString &name, QgsProject *project, const QString &outputName = QString() );
+        LayerDetails( const QString &name, QgsProject *project, const QString &outputName = QString(), QgsProcessingUtils::LayerHint layerTypeHint = QgsProcessingUtils::UnknownType );
 %Docstring
 Constructor for LayerDetails.
 %End
@@ -140,6 +140,8 @@ Default constructor
 
         QString outputName;
 
+        QgsProcessingUtils::LayerHint layerTypeHint;
+
         QgsProcessingLayerPostProcessorInterface *postProcessor() const;
 %Docstring
 Layer post-processor. May be None if no post-processing is required.

python/core/auto_generated/processing/qgsprocessingutils.sip.in

@@ -71,7 +71,14 @@ value.
 .. seealso:: :py:func:`compatibleVectorLayers`
 %End
 
-    static QgsMapLayer *mapLayerFromString( const QString &string, QgsProcessingContext &context, bool allowLoadingNewLayers = true );
+    enum LayerHint
+    {
+      UnknownType,
+      Vector,
+      Raster,
+    };
+
+    static QgsMapLayer *mapLayerFromString( const QString &string, QgsProcessingContext &context, bool allowLoadingNewLayers = true, LayerHint typeHint = UnknownType );
 %Docstring
 Interprets a string as a map layer within the supplied ``context``.
 
@@ -81,6 +88,8 @@ within the context's project or temporary layer store then this layer will be re
 If the string is a file path and ``allowLoadingNewLayers`` is true, then the layer at this
 file path will be loaded and added to the context's temporary layer store.
 Ownership of the layer remains with the ``context`` or the context's current project.
+
+The ``typeHint`` can be used to dictate the type of map layer expected.
 %End
 
     static QgsProcessingFeatureSource *variantToSource( const QVariant &value, QgsProcessingContext &context, const QVariant &fallbackValue = QVariant() ) /Factory/;

python/plugins/processing/gui/Postprocessing.py

@@ -57,7 +57,7 @@ def handleAlgorithmResults(alg, context, feedback=None, showResults=True):
             feedback.setProgress(100 * i / float(len(context.layersToLoadOnCompletion())))
 
         try:
-            layer = QgsProcessingUtils.mapLayerFromString(l, context)
+            layer = QgsProcessingUtils.mapLayerFromString(l, context, typeHint=details.layerTypeHint)
             if layer is not None:
                 if not ProcessingConfig.getSetting(ProcessingConfig.USE_FILENAME_AS_LAYER_NAME):
                     layer.setName(details.name)

src/core/processing/models/qgsprocessingmodelalgorithm.cpp

@@ -591,7 +591,7 @@ QMap<QString, QgsProcessingModelAlgorithm::VariableDefinition> QgsProcessingMode
     }
     if ( !featureSource )
     {
-      if ( QgsVectorLayer *vl = qobject_cast< QgsVectorLayer *>( QgsProcessingUtils::mapLayerFromString( value.toString(), context ) ) )
+      if ( QgsVectorLayer *vl = qobject_cast< QgsVectorLayer *>( QgsProcessingUtils::mapLayerFromString( value.toString(), context, true, QgsProcessingUtils::Vector ) ) )
         featureSource = vl;
     }
 

src/core/processing/qgsprocessingcontext.h

@@ -26,6 +26,7 @@
 #include "qgsmaplayerlistutils.h"
 #include "qgsexception.h"
 #include "qgsprocessingfeedback.h"
+#include "qgsprocessingutils.h"
 
 class QgsProcessingLayerPostProcessorInterface;
 
@@ -169,9 +170,10 @@ class CORE_EXPORT QgsProcessingContext
         /**
          * Constructor for LayerDetails.
          */
-        LayerDetails( const QString &name, QgsProject *project, const QString &outputName = QString() )
+        LayerDetails( const QString &name, QgsProject *project, const QString &outputName = QString(), QgsProcessingUtils::LayerHint layerTypeHint = QgsProcessingUtils::UnknownType )
           : name( name )
           , outputName( outputName )
+          , layerTypeHint( layerTypeHint )
           , project( project )
         {}
 
@@ -184,6 +186,13 @@ class CORE_EXPORT QgsProcessingContext
         //! Associated output name from algorithm which generated the layer.
         QString outputName;
 
+        /**
+         * Layer type hint.
+         *
+         * \since QGIS 3.4
+         */
+        QgsProcessingUtils::LayerHint layerTypeHint = QgsProcessingUtils::UnknownType;
+
         /**
          * Layer post-processor. May be nullptr if no post-processing is required.
          * \see setPostProcessor()

src/core/processing/qgsprocessingparameters.cpp

@@ -140,7 +140,7 @@ int QgsProcessingParameters::parameterAsInt( const QgsProcessingParameterDefinit
       //double too large to fit in int
       return 0;
     }
-    return std::round( dbl );
+    return static_cast< int >( std::round( dbl ) );
   }
 
   return val.toInt();
@@ -290,7 +290,7 @@ QgsFeatureSink *QgsProcessingParameters::parameterAsSink( const QgsProcessingPar
     QString outputName;
     if ( definition )
       outputName = definition->name();
-    context.addLayerToLoadOnCompletion( destinationIdentifier, QgsProcessingContext::LayerDetails( destName, destinationProject, outputName ) );
+    context.addLayerToLoadOnCompletion( destinationIdentifier, QgsProcessingContext::LayerDetails( destName, destinationProject, outputName, QgsProcessingUtils::Vector ) );
   }
 
   return sink.release();
@@ -363,7 +363,7 @@ QString QgsProcessingParameters::parameterAsCompatibleSourceLayerPath( const Qgs
       if ( layerRef.isEmpty() )
         return QString();
 
-      vl = qobject_cast< QgsVectorLayer *>( QgsProcessingUtils::mapLayerFromString( layerRef, context ) );
+      vl = qobject_cast< QgsVectorLayer *>( QgsProcessingUtils::mapLayerFromString( layerRef, context, true, QgsProcessingUtils::Vector ) );
     }
   }
 
@@ -462,7 +462,14 @@ QString QgsProcessingParameters::parameterAsOutputLayer( const QgsProcessingPara
     }
     if ( definition )
       outputName = definition->name();
-    context.addLayerToLoadOnCompletion( dest, QgsProcessingContext::LayerDetails( destName, destinationProject, outputName ) );
+
+    QgsProcessingUtils::LayerHint layerTypeHint = QgsProcessingUtils::UnknownType;
+    if ( definition->type() == QgsProcessingParameterVectorDestination::typeName() )
+      layerTypeHint = QgsProcessingUtils::Vector;
+    else if ( definition->type() == QgsProcessingParameterRasterDestination::typeName() )
+      layerTypeHint = QgsProcessingUtils::Raster;
+
+    context.addLayerToLoadOnCompletion( dest, QgsProcessingContext::LayerDetails( destName, destinationProject, outputName, layerTypeHint ) );
   }
 
   return dest;
@@ -2450,7 +2457,7 @@ bool QgsProcessingParameterRasterLayer::checkValueIsAcceptable( const QVariant &
   }
 
   // try to load as layer
-  if ( QgsProcessingUtils::mapLayerFromString( input.toString(), *context ) )
+  if ( QgsProcessingUtils::mapLayerFromString( input.toString(), *context, true, QgsProcessingUtils::Raster ) )
     return true;
 
   return false;
@@ -2849,7 +2856,7 @@ bool QgsProcessingParameterVectorLayer::checkValueIsAcceptable( const QVariant &
   }
 
   // try to load as layer
-  if ( QgsProcessingUtils::mapLayerFromString( var.toString(), *context ) )
+  if ( QgsProcessingUtils::mapLayerFromString( var.toString(), *context, true, QgsProcessingUtils::Vector ) )
     return true;
 
   return false;
@@ -3180,7 +3187,7 @@ bool QgsProcessingParameterFeatureSource::checkValueIsAcceptable( const QVariant
   }
 
   // try to load as layer
-  if ( QgsProcessingUtils::mapLayerFromString( var.toString(), *context ) )
+  if ( QgsProcessingUtils::mapLayerFromString( var.toString(), *context, true, QgsProcessingUtils::Vector ) )
     return true;
 
   return false;
@@ -3207,7 +3214,7 @@ QString QgsProcessingParameterFeatureSource::valueAsPythonString( const QVariant
       {
         QString layerString = fromVar.source.staticValue().toString();
         // prefer to use layer source instead of id if possible (since it's persistent)
-        if ( QgsVectorLayer *layer = qobject_cast< QgsVectorLayer * >( QgsProcessingUtils::mapLayerFromString( layerString, context ) ) )
+        if ( QgsVectorLayer *layer = qobject_cast< QgsVectorLayer * >( QgsProcessingUtils::mapLayerFromString( layerString, context, true, QgsProcessingUtils::Vector ) ) )
           layerString = layer->source();
         return QgsProcessingUtils::stringToPythonLiteral( layerString );
       }
@@ -3232,7 +3239,7 @@ QString QgsProcessingParameterFeatureSource::valueAsPythonString( const QVariant
   QString layerString = value.toString();
 
   // prefer to use layer source if possible (since it's persistent)
-  if ( QgsVectorLayer *layer = qobject_cast< QgsVectorLayer * >( QgsProcessingUtils::mapLayerFromString( layerString, context ) ) )
+  if ( QgsVectorLayer *layer = qobject_cast< QgsVectorLayer * >( QgsProcessingUtils::mapLayerFromString( layerString, context, true, QgsProcessingUtils::Vector ) ) )
     layerString = layer->source();
 
   return QgsProcessingUtils::stringToPythonLiteral( layerString );

src/core/processing/qgsprocessingutils.cpp

@@ -94,7 +94,7 @@ QList<QgsMapLayer *> QgsProcessingUtils::compatibleLayers( QgsProject *project,
   return layers;
 }
 
-QgsMapLayer *QgsProcessingUtils::mapLayerFromStore( const QString &string, QgsMapLayerStore *store )
+QgsMapLayer *QgsProcessingUtils::mapLayerFromStore( const QString &string, QgsMapLayerStore *store, QgsProcessingUtils::LayerHint typeHint )
 {
   if ( !store || string.isEmpty() )
     return nullptr;
@@ -117,19 +117,35 @@ QgsMapLayer *QgsProcessingUtils::mapLayerFromStore( const QString &string, QgsMa
     return true;
   } ), layers.end() );
 
-  Q_FOREACH ( QgsMapLayer *l, layers )
+  auto isCompatibleType = [typeHint]( QgsMapLayer * l ) -> bool
   {
-    if ( l->id() == string )
+    switch ( typeHint )
+    {
+      case UnknownType:
+        return true;
+
+      case Vector:
+        return l->type() == QgsMapLayer::VectorLayer;
+
+      case Raster:
+        return l->type() == QgsMapLayer::RasterLayer;
+    }
+    return true;
+  };
+
+  for ( QgsMapLayer *l : qgis::as_const( layers ) )
+  {
+    if ( isCompatibleType( l ) && l->id() == string )
       return l;
   }
-  Q_FOREACH ( QgsMapLayer *l, layers )
+  for ( QgsMapLayer *l : qgis::as_const( layers ) )
   {
-    if ( l->name() == string )
+    if ( isCompatibleType( l ) && l->name() == string )
       return l;
   }
-  Q_FOREACH ( QgsMapLayer *l, layers )
+  for ( QgsMapLayer *l : qgis::as_const( layers ) )
   {
-    if ( normalizeLayerSource( l->source() ) == normalizeLayerSource( string ) )
+    if ( isCompatibleType( l ) && normalizeLayerSource( l->source() ) == normalizeLayerSource( string ) )
       return l;
   }
   return nullptr;
@@ -157,7 +173,7 @@ class ProjectionSettingRestorer
 };
 ///@endcond PRIVATE
 
-QgsMapLayer *QgsProcessingUtils::loadMapLayerFromString( const QString &string )
+QgsMapLayer *QgsProcessingUtils::loadMapLayerFromString( const QString &string, LayerHint typeHint )
 {
   QStringList components = string.split( '|' );
   if ( components.isEmpty() )
@@ -178,24 +194,30 @@ QgsMapLayer *QgsProcessingUtils::loadMapLayerFromString( const QString &string )
   QString name = fi.baseName();
 
   // brute force attempt to load a matching layer
-  QgsVectorLayer::LayerOptions options;
-  options.loadDefaultStyle = false;
-  std::unique_ptr< QgsVectorLayer > layer( new QgsVectorLayer( string, name, QStringLiteral( "ogr" ), options ) );
-  if ( layer->isValid() )
+  if ( typeHint == UnknownType || typeHint == Vector )
   {
-    return layer.release();
+    QgsVectorLayer::LayerOptions options;
+    options.loadDefaultStyle = false;
+    std::unique_ptr< QgsVectorLayer > layer( new QgsVectorLayer( string, name, QStringLiteral( "ogr" ), options ) );
+    if ( layer->isValid() )
+    {
+      return layer.release();
+    }
   }
-  QgsRasterLayer::LayerOptions rasterOptions;
-  rasterOptions.loadDefaultStyle = false;
-  std::unique_ptr< QgsRasterLayer > rasterLayer( new QgsRasterLayer( string, name, QStringLiteral( "gdal" ), rasterOptions ) );
-  if ( rasterLayer->isValid() )
+  if ( typeHint == UnknownType || typeHint == Raster )
   {
-    return rasterLayer.release();
+    QgsRasterLayer::LayerOptions rasterOptions;
+    rasterOptions.loadDefaultStyle = false;
+    std::unique_ptr< QgsRasterLayer > rasterLayer( new QgsRasterLayer( string, name, QStringLiteral( "gdal" ), rasterOptions ) );
+    if ( rasterLayer->isValid() )
+    {
+      return rasterLayer.release();
+    }
   }
   return nullptr;
 }
 
-QgsMapLayer *QgsProcessingUtils::mapLayerFromString( const QString &string, QgsProcessingContext &context, bool allowLoadingNewLayers )
+QgsMapLayer *QgsProcessingUtils::mapLayerFromString( const QString &string, QgsProcessingContext &context, bool allowLoadingNewLayers, LayerHint typeHint )
 {
   if ( string.isEmpty() )
     return nullptr;
@@ -204,19 +226,19 @@ QgsMapLayer *QgsProcessingUtils::mapLayerFromString( const QString &string, QgsP
   QgsMapLayer *layer = nullptr;
   if ( context.project() )
   {
-    QgsMapLayer *layer = mapLayerFromStore( string, context.project()->layerStore() );
+    QgsMapLayer *layer = mapLayerFromStore( string, context.project()->layerStore(), typeHint );
     if ( layer )
       return layer;
   }
 
-  layer = mapLayerFromStore( string, context.temporaryLayerStore() );
+  layer = mapLayerFromStore( string, context.temporaryLayerStore(), typeHint );
   if ( layer )
     return layer;
 
   if ( !allowLoadingNewLayers )
     return nullptr;
 
-  layer = loadMapLayerFromString( string );
+  layer = loadMapLayerFromString( string, typeHint );
   if ( layer )
   {
     context.temporaryLayerStore()->addMapLayer( layer );
@@ -274,7 +296,7 @@ QgsProcessingFeatureSource *QgsProcessingUtils::variantToSource( const QVariant
   if ( layerRef.isEmpty() )
     return nullptr;
 
-  QgsVectorLayer *vl = qobject_cast< QgsVectorLayer *>( QgsProcessingUtils::mapLayerFromString( layerRef, context ) );
+  QgsVectorLayer *vl = qobject_cast< QgsVectorLayer *>( QgsProcessingUtils::mapLayerFromString( layerRef, context, true, Vector ) );
   if ( !vl )
     return nullptr;
 

src/core/processing/qgsprocessingutils.h

@@ -86,6 +86,17 @@ class CORE_EXPORT QgsProcessingUtils
      */
     static QList< QgsMapLayer * > compatibleLayers( QgsProject *project, bool sort = true );
 
+    /**
+     * Layer type hints.
+     * \since QGIS 3.4
+     */
+    enum LayerHint
+    {
+      UnknownType, //!< Unknown layer type
+      Vector, //!< Vector layer type
+      Raster, //!< Raster layer type
+    };
+
     /**
      * Interprets a string as a map layer within the supplied \a context.
      *
@@ -95,8 +106,10 @@ class CORE_EXPORT QgsProcessingUtils
      * If the string is a file path and \a allowLoadingNewLayers is true, then the layer at this
      * file path will be loaded and added to the context's temporary layer store.
      * Ownership of the layer remains with the \a context or the context's current project.
+     *
+     * The \a typeHint can be used to dictate the type of map layer expected.
      */
-    static QgsMapLayer *mapLayerFromString( const QString &string, QgsProcessingContext &context, bool allowLoadingNewLayers = true );
+    static QgsMapLayer *mapLayerFromString( const QString &string, QgsProcessingContext &context, bool allowLoadingNewLayers = true, LayerHint typeHint = UnknownType );
 
     /**
      * Converts a variant \a value to a new feature source.
@@ -265,15 +278,15 @@ class CORE_EXPORT QgsProcessingUtils
      * returned.
      * \see mapLayerFromString()
      */
-    static QgsMapLayer *mapLayerFromStore( const QString &string, QgsMapLayerStore *store );
+    static QgsMapLayer *mapLayerFromStore( const QString &string, QgsMapLayerStore *store, LayerHint typeHint = UnknownType );
 
     /**
      * Interprets a string as a map layer. The method will attempt to
      * load a layer matching the passed \a string. E.g. if the string is a file path,
      * then the layer at this file path will be loaded.
      * The caller takes responsibility for deleting the returned map layer.
      */
-    static QgsMapLayer *loadMapLayerFromString( const QString &string );
+    static QgsMapLayer *loadMapLayerFromString( const QString &string, LayerHint typeHint = UnknownType );
 
     static void parseDestinationString( QString &destination, QString &providerKey, QString &uri, QString &layerName, QString &format, QMap<QString, QVariant> &options, bool &useWriter );