[processing] When converting models to Python, use friendlier (more

descriptive) names when storing child algorithm results

Makes for much easier to understand scripts

python/core/auto_generated/processing/models/qgsprocessingmodelchildalgorithm.sip.in

@@ -298,7 +298,7 @@ Loads this child from a QVariant.
 .. seealso:: :py:func:`toVariant`
 %End
 
-    QStringList asPythonCode( QgsProcessing::PythonOutputType outputType, const QgsStringMap &extraParameters, int currentIndent, int indentSize ) const;
+    QStringList asPythonCode( QgsProcessing::PythonOutputType outputType, const QgsStringMap &extraParameters, int currentIndent, int indentSize, const QMap<QString, QString> &friendlyChildNames ) const;
 %Docstring
 Attempts to convert the child to executable Python code, and returns a list of the generated lines of code.
 
@@ -307,6 +307,8 @@ The ``outputType`` argument specifies the type of script to generate.
 Additional parameters to be passed to the child algorithm are specified in the ``extraParameters`` argument.
 
 The ``currentIndent`` and ``indentSize`` are used to set the base line indent and size of further indented lines respectively.
+
+The ``friendlyChildNames`` argument gives a map of child id to a friendly algorithm name, to be used in the code to identify that algorithm instead of the raw child id.
 %End
 
 };

python/core/auto_generated/processing/models/qgsprocessingmodelchildparametersource.sip.in

@@ -240,9 +240,11 @@ Loads this source from a QVariantMap.
 .. seealso:: :py:func:`toVariant`
 %End
 
-    QString asPythonCode( QgsProcessing::PythonOutputType outputType, const QgsProcessingParameterDefinition *definition ) const;
+    QString asPythonCode( QgsProcessing::PythonOutputType outputType, const QgsProcessingParameterDefinition *definition, const QMap< QString, QString > &friendlydChildNames ) const;
 %Docstring
 Attempts to convert the source to executable Python code.
+
+The ``friendlyChildNames`` argument gives a map of child id to a friendly algorithm name, to be used in the code to identify that algorithm instead of the raw child id.
 %End
 
 };

src/core/processing/models/qgsprocessingmodelalgorithm.cpp

@@ -361,23 +361,42 @@ QStringList QgsProcessingModelAlgorithm::asPythonCode( const QgsProcessing::Pyth
   QString indent = QString( ' ' ).repeated( indentSize );
   QString currentIndent;
 
-  auto safeName = []( const QString & name )->QString
+  QMap< QString, QString> friendlyChildNames;
+  auto safeName = []( const QString & name, bool capitalize )->QString
   {
     QString n = name.toLower().trimmed();
     QRegularExpression rx( QStringLiteral( "[^\\sa-z_A-Z0-9]" ) );
     n.replace( rx, QString() );
     QRegularExpression rx2( QStringLiteral( "^\\d*" ) ); // name can't start in a digit
     n.replace( rx2, QString() );
-    return QgsStringUtils::capitalize( n, QgsStringUtils::UpperCamelCase );
+    if ( !capitalize )
+      n = n.replace( ' ', '_' );
+    return capitalize ? QgsStringUtils::capitalize( n, QgsStringUtils::UpperCamelCase ) : n;
   };
 
-  const QString algorithmClassName = safeName( name() );
+  auto uniqueSafeName = [&friendlyChildNames, &safeName ]( const QString & name, bool capitalize )->QString
+  {
+    const QString base = safeName( name, capitalize );
+    QString candidate = base;
+    int i = 1;
+    while ( friendlyChildNames.contains( candidate ) )
+    {
+      i++;
+      candidate = QStringLiteral( "%1_%2" ).arg( base ).arg( i );
+    }
+    return candidate;
+  };
+
+  const QString algorithmClassName = safeName( name(), true );
 
   QSet< QString > toExecute;
   for ( auto childIt = mChildAlgorithms.constBegin(); childIt != mChildAlgorithms.constEnd(); ++childIt )
   {
     if ( childIt->isActive() && childIt->algorithm() )
+    {
       toExecute.insert( childIt->childId() );
+      friendlyChildNames.insert( childIt->childId(), uniqueSafeName( childIt->description().isEmpty() ? childIt->childId() : childIt->description(), !childIt->description().isEmpty() ) );
+    }
   }
   const int totalSteps = toExecute.count();
 
@@ -462,6 +481,7 @@ QStringList QgsProcessingModelAlgorithm::asPythonCode( const QgsProcessing::Pyth
 
   lines << currentIndent + QStringLiteral( "results = {}" );
   lines << currentIndent + QStringLiteral( "outputs = {}" );
+  lines << QString();
 
   QSet< QString > executed;
   bool executedAlg = true;
@@ -536,7 +556,7 @@ QStringList QgsProcessingModelAlgorithm::asPythonCode( const QgsProcessing::Pyth
         }
       }
 
-      lines << child.asPythonCode( outputType, childParams, currentIndent.size(), indentSize );
+      lines << child.asPythonCode( outputType, childParams, currentIndent.size(), indentSize, friendlyChildNames );
       currentStep++;
       if ( currentStep < totalSteps )
       {

src/core/processing/models/qgsprocessingmodelchildalgorithm.cpp

@@ -162,7 +162,7 @@ bool QgsProcessingModelChildAlgorithm::loadVariant( const QVariant &child )
   return true;
 }
 
-QStringList QgsProcessingModelChildAlgorithm::asPythonCode( const QgsProcessing::PythonOutputType outputType, const QgsStringMap &extraParameters, int currentIndent, int indentSize ) const
+QStringList QgsProcessingModelChildAlgorithm::asPythonCode( const QgsProcessing::PythonOutputType outputType, const QgsStringMap &extraParameters, int currentIndent, int indentSize, const QMap<QString, QString> &friendlyChildNames ) const
 {
   QStringList lines;
   const QString baseIndent = QString( ' ' ).repeated( currentIndent );
@@ -181,7 +181,7 @@ QStringList QgsProcessingModelChildAlgorithm::asPythonCode( const QgsProcessing:
     const auto parts = paramIt.value();
     for ( const QgsProcessingModelChildParameterSource &source : parts )
     {
-      QString part = source.asPythonCode( outputType, def );
+      QString part = source.asPythonCode( outputType, def, friendlyChildNames );
       if ( !part.isEmpty() )
         sourceParts << part;
     }
@@ -207,11 +207,11 @@ QStringList QgsProcessingModelChildAlgorithm::asPythonCode( const QgsProcessing:
   }
   lines << baseIndent + QStringLiteral( "}" );
 
-  lines << baseIndent + QStringLiteral( "outputs['%1'] = processing.run('%2', alg_params, context=context, feedback=feedback, is_child_algorithm=True)" ).arg( mId, mAlgorithmId );
+  lines << baseIndent + QStringLiteral( "outputs['%1'] = processing.run('%2', alg_params, context=context, feedback=feedback, is_child_algorithm=True)" ).arg( friendlyChildNames.value( mId, mId ), mAlgorithmId );
 
   for ( auto outputIt = mModelOutputs.constBegin(); outputIt != mModelOutputs.constEnd(); ++outputIt )
   {
-    lines << baseIndent + QStringLiteral( "results['%1:%2'] = outputs['%1']['%3']" ).arg( mId, outputIt.key(), outputIt.value().childOutputName() );
+    lines << baseIndent + QStringLiteral( "results['%1:%2'] = outputs['%3']['%4']" ).arg( mId, outputIt.key(), friendlyChildNames.value( mId, mId ), outputIt.value().childOutputName() );
   }
 
   return lines;

src/core/processing/models/qgsprocessingmodelchildalgorithm.h

@@ -285,8 +285,10 @@ class CORE_EXPORT QgsProcessingModelChildAlgorithm : public QgsProcessingModelCo
      * Additional parameters to be passed to the child algorithm are specified in the \a extraParameters argument.
      *
      * The \a currentIndent and \a indentSize are used to set the base line indent and size of further indented lines respectively.
+     *
+     * The \a friendlyChildNames argument gives a map of child id to a friendly algorithm name, to be used in the code to identify that algorithm instead of the raw child id.
      */
-    QStringList asPythonCode( QgsProcessing::PythonOutputType outputType, const QgsStringMap &extraParameters, int currentIndent, int indentSize ) const;
+    QStringList asPythonCode( QgsProcessing::PythonOutputType outputType, const QgsStringMap &extraParameters, int currentIndent, int indentSize, const QMap<QString, QString> &friendlyChildNames ) const;
 
   private:
 

src/core/processing/models/qgsprocessingmodelchildparametersource.cpp

@@ -147,15 +147,15 @@ bool QgsProcessingModelChildParameterSource::loadVariant( const QVariantMap &map
   return true;
 }
 
-QString QgsProcessingModelChildParameterSource::asPythonCode( const QgsProcessing::PythonOutputType, const QgsProcessingParameterDefinition *definition ) const
+QString QgsProcessingModelChildParameterSource::asPythonCode( const QgsProcessing::PythonOutputType, const QgsProcessingParameterDefinition *definition, const QMap< QString, QString > &friendlydChildNames ) const
 {
   switch ( mSource )
   {
     case ModelParameter:
       return QStringLiteral( "parameters['%1']" ).arg( mParameterName );
 
     case ChildOutput:
-      return QStringLiteral( "outputs['%1']['%2']" ).arg( mChildId, mOutputName );
+      return QStringLiteral( "outputs['%1']['%2']" ).arg( friendlydChildNames.value( mChildId, mChildId ), mOutputName );
 
     case StaticValue:
       if ( definition )

src/core/processing/models/qgsprocessingmodelchildparametersource.h

@@ -215,8 +215,10 @@ class CORE_EXPORT QgsProcessingModelChildParameterSource
 
     /**
      * Attempts to convert the source to executable Python code.
+     *
+     * The \a friendlyChildNames argument gives a map of child id to a friendly algorithm name, to be used in the code to identify that algorithm instead of the raw child id.
      */
-    QString asPythonCode( QgsProcessing::PythonOutputType outputType, const QgsProcessingParameterDefinition *definition ) const;
+    QString asPythonCode( QgsProcessing::PythonOutputType outputType, const QgsProcessingParameterDefinition *definition, const QMap< QString, QString > &friendlydChildNames ) const;
 
   private: