Also add "Run from Here" action to right click menu on algorithms

Allows running the part of the model which starts at the right
clicked algorithm only

python/PyQt6/gui/auto_generated/processing/models/qgsmodelcomponentgraphicitem.sip.in

@@ -403,6 +403,13 @@ Sets the ``results`` obtained for this child algorithm for the last model execut
 
   signals:
 
+    void runFromHere();
+%Docstring
+Emitted when the user opts to run the model from this child algorithm.
+
+.. versionadded:: 3.38
+%End
+
     void showPreviousResults();
 %Docstring
 Emitted when the user opts to view previous results from this child algorithm.

python/PyQt6/gui/auto_generated/processing/models/qgsmodelgraphicsscene.sip.in

@@ -172,6 +172,13 @@ Emitted whenever a component of the model is changed.
 %Docstring
 Emitted whenever the selected item changes.
 If ``None``, no item is selected.
+%End
+
+    void runFromChild( const QString &childId );
+%Docstring
+Emitted when the user opts to run the part of the model starting from the specified child algorithm.
+
+.. versionadded:: 3.38
 %End
 
     void showChildAlgorithmOutputs( const QString &childId );

python/gui/auto_generated/processing/models/qgsmodelcomponentgraphicitem.sip.in

@@ -403,6 +403,13 @@ Sets the ``results`` obtained for this child algorithm for the last model execut
 
   signals:
 
+    void runFromHere();
+%Docstring
+Emitted when the user opts to run the model from this child algorithm.
+
+.. versionadded:: 3.38
+%End
+
     void showPreviousResults();
 %Docstring
 Emitted when the user opts to view previous results from this child algorithm.

python/gui/auto_generated/processing/models/qgsmodelgraphicsscene.sip.in

@@ -172,6 +172,13 @@ Emitted whenever a component of the model is changed.
 %Docstring
 Emitted whenever the selected item changes.
 If ``None``, no item is selected.
+%End
+
+    void runFromChild( const QString &childId );
+%Docstring
+Emitted when the user opts to run the part of the model starting from the specified child algorithm.
+
+.. versionadded:: 3.38
 %End
 
     void showChildAlgorithmOutputs( const QString &childId );

src/gui/processing/models/qgsmodelcomponentgraphicitem.cpp

@@ -870,6 +870,11 @@ QgsModelChildAlgorithmGraphicItem::QgsModelChildAlgorithmGraphicItem( QgsProcess
 void QgsModelChildAlgorithmGraphicItem::contextMenuEvent( QGraphicsSceneContextMenuEvent *event )
 {
   QMenu *popupmenu = new QMenu( event->widget() );
+  QAction *runFromHereAction = popupmenu->addAction( QObject::tr( "Run from Here…" ) );
+  runFromHereAction->setIcon( QgsApplication::getThemeIcon( QStringLiteral( "mActionStart.svg" ) ) );
+  connect( runFromHereAction, &QAction::triggered, this, &QgsModelChildAlgorithmGraphicItem::runFromHere );
+  popupmenu->addSeparator();
+
   QAction *removeAction = popupmenu->addAction( QObject::tr( "Remove" ) );
   connect( removeAction, &QAction::triggered, this, &QgsModelChildAlgorithmGraphicItem::deleteComponent );
   QAction *editAction = popupmenu->addAction( QObject::tr( "Edit…" ) );

src/gui/processing/models/qgsmodelcomponentgraphicitem.h

@@ -468,6 +468,13 @@ class GUI_EXPORT QgsModelChildAlgorithmGraphicItem : public QgsModelComponentGra
 
   signals:
 
+    /**
+     * Emitted when the user opts to run the model from this child algorithm.
+     *
+     * \since QGIS 3.38
+    */
+    void runFromHere();
+
     /**
      * Emitted when the user opts to view previous results from this child algorithm.
      *

src/gui/processing/models/qgsmodeldesignerdialog.cpp

@@ -513,6 +513,7 @@ void QgsModelDesignerDialog::setModelScene( QgsModelGraphicsScene *scene )
   } );
   connect( mScene, &QgsModelGraphicsScene::componentAboutToChange, this, [ = ]( const QString & description, int id ) { beginUndoCommand( description, id ); } );
   connect( mScene, &QgsModelGraphicsScene::componentChanged, this, [ = ] { endUndoCommand(); } );
+  connect( mScene, &QgsModelGraphicsScene::runFromChild, this, &QgsModelDesignerDialog::runFromChild );
   connect( mScene, &QgsModelGraphicsScene::showChildAlgorithmOutputs, this, &QgsModelDesignerDialog::showChildAlgorithmOutputs );
   connect( mScene, &QgsModelGraphicsScene::showChildAlgorithmLog, this, &QgsModelDesignerDialog::showChildAlgorithmLog );
 
@@ -1015,6 +1016,13 @@ void QgsModelDesignerDialog::runSelectedSteps()
   run( children );
 }
 
+void QgsModelDesignerDialog::runFromChild( const QString &id )
+{
+  QSet<QString> children = mModel->dependentChildAlgorithms( id );
+  children.insert( id );
+  run( children );
+}
+
 void QgsModelDesignerDialog::run( const QSet<QString> &childAlgorithmSubset )
 {
   QStringList errors;

src/gui/processing/models/qgsmodeldesignerdialog.h

@@ -185,6 +185,7 @@ class GUI_EXPORT QgsModelDesignerDialog : public QMainWindow, public Ui::QgsMode
     void setPanelVisibility( bool hidden );
     void editHelp();
     void runSelectedSteps();
+    void runFromChild( const QString &id );
     void run( const QSet<QString> &childAlgorithmSubset = QSet<QString>() );
     void showChildAlgorithmOutputs( const QString &childId );
     void showChildAlgorithmLog( const QString &childId );

src/gui/processing/models/qgsmodelgraphicsscene.cpp

@@ -145,6 +145,10 @@ void QgsModelGraphicsScene::createItems( QgsProcessingModelAlgorithm *model, Qgs
     connect( item, &QgsModelComponentGraphicItem::requestModelRepaint, this, &QgsModelGraphicsScene::rebuildRequired );
     connect( item, &QgsModelComponentGraphicItem::changed, this, &QgsModelGraphicsScene::componentChanged );
     connect( item, &QgsModelComponentGraphicItem::aboutToChange, this, &QgsModelGraphicsScene::componentAboutToChange );
+    connect( item, &QgsModelChildAlgorithmGraphicItem::runFromHere, this, [this, childId]
+    {
+      emit runFromChild( childId );
+    } );
     connect( item, &QgsModelChildAlgorithmGraphicItem::showPreviousResults, this, [this, childId]
     {
       emit showChildAlgorithmOutputs( childId );

src/gui/processing/models/qgsmodelgraphicsscene.h

@@ -187,6 +187,13 @@ class GUI_EXPORT QgsModelGraphicsScene : public QGraphicsScene
      */
     void selectedItemChanged( QgsModelComponentGraphicItem *selected );
 
+    /**
+     * Emitted when the user opts to run the part of the model starting from the specified child algorithm.
+     *
+     * \since QGIS 3.38
+     */
+    void runFromChild( const QString &childId );
+
     /**
      * Emitted when the user opts to view previous results from the child algorithm with matching ID.
      *