Add method to determine whether dependencies exist between model parameters

Author: nyalldawson

python/core/processing/qgsprocessingmodelalgorithm.sip

@@ -724,6 +724,16 @@ Copies are protected to avoid slicing
 %Docstring
  Returns true if any child algorithms depend on the model parameter
  with the specified ``name``.
+.. seealso:: otherParametersDependOnParameter()
+ :rtype: bool
+%End
+
+    bool otherParametersDependOnParameter( const QString &name ) const;
+%Docstring
+ Returns true if any other model parameters depend on the parameter
+ with the specified ``name`` (e.g. field parameters where ``name``
+ is the parent layer parameter).
+.. seealso:: childAlgorithmsDependOnParameter()
  :rtype: bool
 %End
 

src/core/processing/qgsprocessingmodelalgorithm.cpp

@@ -949,6 +949,19 @@ bool QgsProcessingModelAlgorithm::childAlgorithmsDependOnParameter( const QStrin
   return false;
 }
 
+bool QgsProcessingModelAlgorithm::otherParametersDependOnParameter( const QString &name ) const
+{
+  Q_FOREACH ( const QgsProcessingParameterDefinition *def, mParameters )
+  {
+    if ( def->name() == name )
+      continue;
+
+    if ( def->dependsOnOtherParameters().contains( name ) )
+      return true;
+  }
+  return false;
+}
+
 QMap<QString, QgsProcessingModelAlgorithm::ModelParameter> QgsProcessingModelAlgorithm::parameterComponents() const
 {
   return mParameterComponents;

src/core/processing/qgsprocessingmodelalgorithm.h

@@ -718,9 +718,18 @@ class CORE_EXPORT QgsProcessingModelAlgorithm : public QgsProcessingAlgorithm
     /**
      * Returns true if any child algorithms depend on the model parameter
      * with the specified \a name.
+     * \see otherParametersDependOnParameter()
      */
     bool childAlgorithmsDependOnParameter( const QString &name ) const;
 
+    /**
+     * Returns true if any other model parameters depend on the parameter
+     * with the specified \a name (e.g. field parameters where \a name
+     * is the parent layer parameter).
+     * \see childAlgorithmsDependOnParameter()
+     */
+    bool otherParametersDependOnParameter( const QString &name ) const;
+
     /**
      * Returns the map of parameter components used by the model. The keys
      * should match the algorithm's parameter names (see parameterDefinitions() ).

tests/src/core/testqgsprocessing.cpp

@@ -4458,6 +4458,16 @@ void TestQgsProcessing::modelerAlgorithm()
   alg4.setChildAlgorithm( c10 );
   QVERIFY( alg4.childAlgorithmsDependOnParameter( "p1" ) );
 
+  QgsProcessingModelAlgorithm::ModelParameter vlP;
+  alg4.addModelParameter( new QgsProcessingParameterVectorLayer( "layer" ), vlP );
+  QgsProcessingModelAlgorithm::ModelParameter field;
+  alg4.addModelParameter( new QgsProcessingParameterField( "field", QString(), QVariant(), QStringLiteral( "layer" ) ), field );
+  QVERIFY( !alg4.otherParametersDependOnParameter( "p1" ) );
+  QVERIFY( !alg4.otherParametersDependOnParameter( "field" ) );
+  QVERIFY( alg4.otherParametersDependOnParameter( "layer" ) );
+
+
+
 
 
   // to/from XML