[processing] Force model outputs to respect constraints set by

their underlying algorithm's provider

E.g. for model outputs generated by a saga algorithm, only
sdat and shp files are valid outputs. So only give users choices
of these instead of all formats.

Also fixes temporary file names generated as part of model
execution may use formats which are not compatible with the
algorithm's provider.

Fixes #18908

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

@@ -1901,6 +1901,19 @@ Sets whether the destination should be created by default. For optional paramete
 a value of false indicates that the destination should not be created by default.
 
 .. seealso:: :py:func:`createByDefault`
+%End
+
+  protected:
+
+    QgsProcessingProvider *originalProvider() const;
+%Docstring
+Original (source) provider which this parameter has been derived from.
+In the case of destination parameters which are part of model algorithms, this
+will reflect the child algorithm's provider which actually generates the
+parameter, as opposed to the provider which this parameter belongs to (i.e.
+the model provider)
+
+.. versionadded:: 3.2
 %End
 
 };
@@ -1948,6 +1961,15 @@ Returns the type name for the parameter class.
     virtual QString defaultFileExtension() const;
 
 
+    virtual QStringList supportedOutputVectorLayerExtensions() const;
+%Docstring
+Returns a list of the vector format file extensions supported by this parameter.
+
+.. seealso:: :py:func:`defaultFileExtension`
+
+.. versionadded:: 3.2
+%End
+
     QgsProcessing::SourceType dataType() const;
 %Docstring
 Returns the layer type for sinks associated with the parameter.
@@ -2029,6 +2051,15 @@ Returns the type name for the parameter class.
     virtual QString defaultFileExtension() const;
 
 
+    virtual QStringList supportedOutputVectorLayerExtensions() const;
+%Docstring
+Returns a list of the vector format file extensions supported by this parameter.
+
+.. seealso:: :py:func:`defaultFileExtension`
+
+.. versionadded:: 3.2
+%End
+
     QgsProcessing::SourceType dataType() const;
 %Docstring
 Returns the layer type for this created vector layer.
@@ -2103,6 +2134,15 @@ Returns the type name for the parameter class.
     virtual QString defaultFileExtension() const;
 
 
+    virtual QStringList supportedOutputRasterLayerExtensions() const;
+%Docstring
+Returns a list of the raster format file extensions supported for this parameter.
+
+.. seealso:: :py:func:`defaultFileExtension`
+
+.. versionadded:: 3.2
+%End
+
     static QgsProcessingParameterRasterDestination *fromScriptCode( const QString &name, const QString &description, bool isOptional, const QString &definition ) /Factory/;
 %Docstring
 Creates a new parameter using the definition from a script code.

python/plugins/processing/gui/ParameterGuiUtils.py

@@ -68,18 +68,12 @@ def getFileFilter(param):
     elif param.type() == 'raster':
         return QgsProviderRegistry.instance().fileRasterFilters()
     elif param.type() == 'rasterDestination':
-        if param.provider() is not None:
-            exts = param.provider().supportedOutputRasterLayerExtensions()
-        else:
-            exts = QgsRasterFileWriter.supportedFormatExtensions()
+        exts = param.supportedOutputRasterLayerExtensions()
         for i in range(len(exts)):
             exts[i] = tr('{0} files (*.{1})', 'ParameterRaster').format(exts[i].upper(), exts[i].lower())
         return ';;'.join(exts) + ';;' + tr('All files (*.*)')
     elif param.type() in ('sink', 'vectorDestination'):
-        if param.provider() is not None:
-            exts = param.provider().supportedOutputVectorLayerExtensions()
-        else:
-            exts = QgsVectorFileWriter.supportedFormatExtensions()
+        exts = param.supportedOutputVectorLayerExtensions()
         for i in range(len(exts)):
             exts[i] = tr('{0} files (*.{1})', 'ParameterVector').format(exts[i].upper(), exts[i].lower())
         return ';;'.join(exts) + ';;' + tr('All files (*.*)')

src/core/processing/models/qgsprocessingmodelalgorithm.cpp

@@ -791,7 +791,18 @@ void QgsProcessingModelAlgorithm::updateDestinationParameters()
       param->setName( outputIt->childId() + ':' + outputIt->name() );
       param->setDescription( outputIt->description() );
       param->setDefaultValue( outputIt->defaultValue() );
-      addParameter( param.release() );
+
+      QgsProcessingDestinationParameter *newDestParam = dynamic_cast< QgsProcessingDestinationParameter * >( param.get() );
+      if ( addParameter( param.release() ) && newDestParam )
+      {
+        if ( QgsProcessingProvider *provider = childIt->algorithm()->provider() )
+        {
+          // we need to copy the constraints given by the provider which creates this output across
+          // and replace those which have been set to match the model provider's constraints
+          newDestParam->setSupportsNonFileBasedOutput( provider->supportsNonFileBasedOutput() );
+          newDestParam->mOriginalProvider = provider;
+        }
+      }
     }
   }
 }

src/core/processing/qgsprocessingparameters.cpp

@@ -27,6 +27,7 @@
 #include "qgsreferencedgeometry.h"
 #include "qgsprocessingregistry.h"
 #include "qgsprocessingparametertype.h"
+#include "qgsrasterfilewriter.h"
 #include <functional>
 
 
@@ -3366,7 +3367,11 @@ QgsProcessingOutputDefinition *QgsProcessingParameterFeatureSink::toOutputDefini
 
 QString QgsProcessingParameterFeatureSink::defaultFileExtension() const
 {
-  if ( QgsProcessingProvider *p = provider() )
+  if ( originalProvider() )
+  {
+    return originalProvider()->defaultVectorFileExtension( hasGeometry() );
+  }
+  else if ( QgsProcessingProvider *p = provider() )
   {
     return p->defaultVectorFileExtension( hasGeometry() );
   }
@@ -3384,6 +3389,22 @@ QString QgsProcessingParameterFeatureSink::defaultFileExtension() const
   }
 }
 
+QStringList QgsProcessingParameterFeatureSink::supportedOutputVectorLayerExtensions() const
+{
+  if ( originalProvider() )
+  {
+    return originalProvider()->supportedOutputVectorLayerExtensions();
+  }
+  else if ( QgsProcessingProvider *p = provider() )
+  {
+    return p->supportedOutputVectorLayerExtensions();
+  }
+  else
+  {
+    return QgsVectorFileWriter::supportedFormatExtensions();
+  }
+}
+
 QgsProcessing::SourceType QgsProcessingParameterFeatureSink::dataType() const
 {
   return mDataType;
@@ -3538,7 +3559,11 @@ QgsProcessingOutputDefinition *QgsProcessingParameterRasterDestination::toOutput
 
 QString QgsProcessingParameterRasterDestination::defaultFileExtension() const
 {
-  if ( QgsProcessingProvider *p = provider() )
+  if ( originalProvider() )
+  {
+    return originalProvider()->defaultRasterFileExtension();
+  }
+  else if ( QgsProcessingProvider *p = provider() )
   {
     return p->defaultRasterFileExtension();
   }
@@ -3549,6 +3574,22 @@ QString QgsProcessingParameterRasterDestination::defaultFileExtension() const
   }
 }
 
+QStringList QgsProcessingParameterRasterDestination::supportedOutputRasterLayerExtensions() const
+{
+  if ( originalProvider() )
+  {
+    return originalProvider()->supportedOutputRasterLayerExtensions();
+  }
+  else if ( QgsProcessingProvider *p = provider() )
+  {
+    return p->supportedOutputRasterLayerExtensions();
+  }
+  else
+  {
+    return QgsRasterFileWriter::supportedFormatExtensions();
+  }
+}
+
 QgsProcessingParameterRasterDestination *QgsProcessingParameterRasterDestination::fromScriptCode( const QString &name, const QString &description, bool isOptional, const QString &definition )
 {
   return new QgsProcessingParameterRasterDestination( name, description, definition.isEmpty() ? QVariant() : definition, isOptional );
@@ -3886,7 +3927,11 @@ QgsProcessingOutputDefinition *QgsProcessingParameterVectorDestination::toOutput
 
 QString QgsProcessingParameterVectorDestination::defaultFileExtension() const
 {
-  if ( QgsProcessingProvider *p = provider() )
+  if ( originalProvider() )
+  {
+    return originalProvider()->defaultVectorFileExtension( hasGeometry() );
+  }
+  else if ( QgsProcessingProvider *p = provider() )
   {
     return p->defaultVectorFileExtension( hasGeometry() );
   }
@@ -3904,6 +3949,22 @@ QString QgsProcessingParameterVectorDestination::defaultFileExtension() const
   }
 }
 
+QStringList QgsProcessingParameterVectorDestination::supportedOutputVectorLayerExtensions() const
+{
+  if ( originalProvider() )
+  {
+    return originalProvider()->supportedOutputVectorLayerExtensions();
+  }
+  else if ( QgsProcessingProvider *p = provider() )
+  {
+    return p->supportedOutputVectorLayerExtensions();
+  }
+  else
+  {
+    return QgsVectorFileWriter::supportedFormatExtensions();
+  }
+}
+
 QgsProcessing::SourceType QgsProcessingParameterVectorDestination::dataType() const
 {
   return mDataType;

src/core/processing/qgsprocessingparameters.h

@@ -1831,11 +1831,34 @@ class CORE_EXPORT QgsProcessingDestinationParameter : public QgsProcessingParame
      */
     void setCreateByDefault( bool createByDefault );
 
+  protected:
+
+    /**
+     * Original (source) provider which this parameter has been derived from.
+     * In the case of destination parameters which are part of model algorithms, this
+     * will reflect the child algorithm's provider which actually generates the
+     * parameter, as opposed to the provider which this parameter belongs to (i.e.
+     * the model provider)
+     * \since QGIS 3.2
+     */
+    QgsProcessingProvider *originalProvider() const { return mOriginalProvider; }
+
   private:
 
+    /**
+     * Original (source) provider which this parameter has been derived from.
+     * In the case of destination parameters which are part of model algorithms, this
+     * will reflect the child algorithm's provider which actually generates the
+     * parameter, as opposed to the provider which this parameter belongs to (i.e.
+     * the model provider)
+     */
+    QgsProcessingProvider *mOriginalProvider = nullptr;
+
     bool mSupportsNonFileBasedOutputs = true;
     bool mCreateByDefault = true;
 
+    friend class QgsProcessingModelAlgorithm;
+    friend class TestQgsProcessing;
 };
 
 
@@ -1872,6 +1895,13 @@ class CORE_EXPORT QgsProcessingParameterFeatureSink : public QgsProcessingDestin
     QgsProcessingOutputDefinition *toOutputDefinition() const override SIP_FACTORY;
     QString defaultFileExtension() const override;
 
+    /**
+     * Returns a list of the vector format file extensions supported by this parameter.
+     * \see defaultFileExtension()
+     * \since QGIS 3.2
+     */
+    virtual QStringList supportedOutputVectorLayerExtensions() const;
+
     /**
      * Returns the layer type for sinks associated with the parameter.
      * \see setDataType()
@@ -1940,6 +1970,13 @@ class CORE_EXPORT QgsProcessingParameterVectorDestination : public QgsProcessing
     QgsProcessingOutputDefinition *toOutputDefinition() const override SIP_FACTORY;
     QString defaultFileExtension() const override;
 
+    /**
+     * Returns a list of the vector format file extensions supported by this parameter.
+     * \see defaultFileExtension()
+     * \since QGIS 3.2
+     */
+    virtual QStringList supportedOutputVectorLayerExtensions() const;
+
     /**
      * Returns the layer type for this created vector layer.
      * \see setDataType()
@@ -2005,6 +2042,13 @@ class CORE_EXPORT QgsProcessingParameterRasterDestination : public QgsProcessing
     QgsProcessingOutputDefinition *toOutputDefinition() const override SIP_FACTORY;
     QString defaultFileExtension() const override;
 
+    /**
+     * Returns a list of the raster format file extensions supported for this parameter.
+     * \see defaultFileExtension()
+     * \since QGIS 3.2
+     */
+    virtual QStringList supportedOutputRasterLayerExtensions() const;
+
     /**
      * Creates a new parameter using the definition from a script code.
      */

tests/src/analysis/testqgsprocessing.cpp

@@ -404,6 +404,62 @@ class DummyProvider3 : public QgsProcessingProvider
 
 };
 
+class DummyAlgorithm2 : public QgsProcessingAlgorithm
+{
+  public:
+
+    DummyAlgorithm2( const QString &name ) : mName( name ) { mFlags = QgsProcessingAlgorithm::flags(); }
+
+    void initAlgorithm( const QVariantMap & = QVariantMap() ) override
+    {
+      addParameter( new QgsProcessingParameterVectorDestination( QStringLiteral( "vector_dest" ) ) );
+      addParameter( new QgsProcessingParameterRasterDestination( QStringLiteral( "raster_dest" ) ) );
+      addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "sink" ) ) );
+    }
+    QString name() const override { return mName; }
+    QString displayName() const override { return mName; }
+    QVariantMap processAlgorithm( const QVariantMap &, QgsProcessingContext &, QgsProcessingFeedback * ) override { return QVariantMap(); }
+
+    Flags flags() const override { return mFlags; }
+    DummyAlgorithm2 *createInstance() const override { return new DummyAlgorithm2( name() ); }
+
+    QString mName;
+
+    Flags mFlags;
+
+};
+
+
+class DummyProvider4 : public QgsProcessingProvider
+{
+  public:
+
+    DummyProvider4()  = default;
+    QString id() const override { return QStringLiteral( "dummy4" ); }
+    QString name() const override { return QStringLiteral( "dummy4" ); }
+
+    bool supportsNonFileBasedOutput() const override
+    {
+      return false;
+    }
+
+    QStringList supportedOutputVectorLayerExtensions() const override
+    {
+      return QStringList() << QStringLiteral( "mif" );
+    }
+
+    QStringList supportedOutputRasterLayerExtensions() const override
+    {
+      return QStringList() << QStringLiteral( "mig" );
+    }
+
+    void loadAlgorithms() override
+    {
+      QVERIFY( addAlgorithm( new DummyAlgorithm2( "alg1" ) ) );
+    }
+
+};
+
 class DummyParameterType : public QgsProcessingParameterType
 {
 
@@ -494,6 +550,7 @@ class TestQgsProcessing: public QObject
     void asPythonCommand();
     void modelerAlgorithm();
     void modelExecution();
+    void modelWithProviderWithLimitedTypes();
     void modelVectorOutputIsCompatibleType();
     void modelAcceptableValues();
     void tempUtils();
@@ -5807,6 +5864,7 @@ void TestQgsProcessing::modelerAlgorithm()
   QCOMPARE( alg7.destinationParameterDefinitions().count(), 1 );
   QCOMPARE( alg7.destinationParameterDefinitions().at( 0 )->name(), QStringLiteral( "cx1:my_output" ) );
   QCOMPARE( alg7.destinationParameterDefinitions().at( 0 )->description(), QStringLiteral( "my output" ) );
+  QCOMPARE( static_cast< const QgsProcessingDestinationParameter * >( alg7.destinationParameterDefinitions().at( 0 ) )->originalProvider()->id(), QStringLiteral( "native" ) );
   QCOMPARE( alg7.outputDefinitions().count(), 1 );
   QCOMPARE( alg7.outputDefinitions().at( 0 )->name(), QStringLiteral( "cx1:my_output" ) );
   QCOMPARE( alg7.outputDefinitions().at( 0 )->type(), QStringLiteral( "outputVector" ) );
@@ -6083,6 +6141,59 @@ void TestQgsProcessing::modelExecution()
   QCOMPARE( actualParts, expectedParts );
 }
 
+void TestQgsProcessing::modelWithProviderWithLimitedTypes()
+{
+  QgsApplication::processingRegistry()->addProvider( new DummyProvider4() );
+
+  QgsProcessingModelAlgorithm alg( "test", "testGroup" );
+  QgsProcessingModelChildAlgorithm algc1;
+  algc1.setChildId( "cx1" );
+  algc1.setAlgorithmId( "dummy4:alg1" );
+  QMap<QString, QgsProcessingModelOutput> algc1outputs;
+  QgsProcessingModelOutput algc1out1( QStringLiteral( "my_vector_output" ) );
+  algc1out1.setChildId( "cx1" );
+  algc1out1.setChildOutputName( "vector_dest" );
+  algc1out1.setDescription( QStringLiteral( "my output" ) );
+  algc1outputs.insert( QStringLiteral( "my_vector_output" ), algc1out1 );
+  QgsProcessingModelOutput algc1out2( QStringLiteral( "my_raster_output" ) );
+  algc1out2.setChildId( "cx1" );
+  algc1out2.setChildOutputName( "raster_dest" );
+  algc1out2.setDescription( QStringLiteral( "my output" ) );
+  algc1outputs.insert( QStringLiteral( "my_raster_output" ), algc1out2 );
+  QgsProcessingModelOutput algc1out3( QStringLiteral( "my_sink_output" ) );
+  algc1out3.setChildId( "cx1" );
+  algc1out3.setChildOutputName( "sink" );
+  algc1out3.setDescription( QStringLiteral( "my output" ) );
+  algc1outputs.insert( QStringLiteral( "my_sink_output" ), algc1out3 );
+  algc1.setModelOutputs( algc1outputs );
+  alg.addChildAlgorithm( algc1 );
+  // verify that model has destination parameter created
+  QCOMPARE( alg.destinationParameterDefinitions().count(), 3 );
+  QCOMPARE( alg.destinationParameterDefinitions().at( 2 )->name(), QStringLiteral( "cx1:my_vector_output" ) );
+  QCOMPARE( alg.destinationParameterDefinitions().at( 2 )->description(), QStringLiteral( "my output" ) );
+  QCOMPARE( static_cast< const QgsProcessingDestinationParameter * >( alg.destinationParameterDefinitions().at( 2 ) )->originalProvider()->id(), QStringLiteral( "dummy4" ) );
+  QCOMPARE( static_cast< const QgsProcessingParameterVectorDestination * >( alg.destinationParameterDefinitions().at( 2 ) )->supportedOutputVectorLayerExtensions(), QStringList() << QStringLiteral( "mif" ) );
+  QCOMPARE( static_cast< const QgsProcessingParameterVectorDestination * >( alg.destinationParameterDefinitions().at( 2 ) )->defaultFileExtension(), QStringLiteral( "mif" ) );
+  QVERIFY( static_cast< const QgsProcessingParameterVectorDestination * >( alg.destinationParameterDefinitions().at( 2 ) )->generateTemporaryDestination().endsWith( QStringLiteral( ".mif" ) ) );
+  QVERIFY( !static_cast< const QgsProcessingDestinationParameter * >( alg.destinationParameterDefinitions().at( 2 ) )->supportsNonFileBasedOutput() );
+
+  QCOMPARE( alg.destinationParameterDefinitions().at( 0 )->name(), QStringLiteral( "cx1:my_raster_output" ) );
+  QCOMPARE( alg.destinationParameterDefinitions().at( 0 )->description(), QStringLiteral( "my output" ) );
+  QCOMPARE( static_cast< const QgsProcessingDestinationParameter * >( alg.destinationParameterDefinitions().at( 0 ) )->originalProvider()->id(), QStringLiteral( "dummy4" ) );
+  QCOMPARE( static_cast< const QgsProcessingParameterRasterDestination * >( alg.destinationParameterDefinitions().at( 0 ) )->supportedOutputRasterLayerExtensions(), QStringList() << QStringLiteral( "mig" ) );
+  QCOMPARE( static_cast< const QgsProcessingParameterRasterDestination * >( alg.destinationParameterDefinitions().at( 0 ) )->defaultFileExtension(), QStringLiteral( "mig" ) );
+  QVERIFY( static_cast< const QgsProcessingParameterRasterDestination * >( alg.destinationParameterDefinitions().at( 0 ) )->generateTemporaryDestination().endsWith( QStringLiteral( ".mig" ) ) );
+  QVERIFY( !static_cast< const QgsProcessingDestinationParameter * >( alg.destinationParameterDefinitions().at( 0 ) )->supportsNonFileBasedOutput() );
+
+  QCOMPARE( alg.destinationParameterDefinitions().at( 1 )->name(), QStringLiteral( "cx1:my_sink_output" ) );
+  QCOMPARE( alg.destinationParameterDefinitions().at( 1 )->description(), QStringLiteral( "my output" ) );
+  QCOMPARE( static_cast< const QgsProcessingDestinationParameter * >( alg.destinationParameterDefinitions().at( 1 ) )->originalProvider()->id(), QStringLiteral( "dummy4" ) );
+  QCOMPARE( static_cast< const QgsProcessingParameterFeatureSink * >( alg.destinationParameterDefinitions().at( 1 ) )->supportedOutputVectorLayerExtensions(), QStringList() << QStringLiteral( "mif" ) );
+  QCOMPARE( static_cast< const QgsProcessingParameterFeatureSink * >( alg.destinationParameterDefinitions().at( 1 ) )->defaultFileExtension(), QStringLiteral( "mif" ) );
+  QVERIFY( static_cast< const QgsProcessingParameterFeatureSink * >( alg.destinationParameterDefinitions().at( 1 ) )->generateTemporaryDestination().endsWith( QStringLiteral( ".mif" ) ) );
+  QVERIFY( !static_cast< const QgsProcessingDestinationParameter * >( alg.destinationParameterDefinitions().at( 1 ) )->supportsNonFileBasedOutput() );
+}
+
 void TestQgsProcessing::modelVectorOutputIsCompatibleType()
 {
   // IMPORTANT: This method is intended to be "permissive" rather than "restrictive".