Use /TransferBack/ instead of /Factory/ in layout registry factory me…

…thods

For same reason as we do in Processing registry:

(from the comments included in this commit)
"
While it seems like /Factory/ would be the correct annotations here, that's not
the case.
As per Phil Thomson's advice on https://www.riverbankcomputing.com/pipermail/pyqt/2017-July/039450.html:

"
/Factory/ is used when the instance returned is guaranteed to be new to Python.
In this case it isn't because it has already been seen when being returned by QgsProcessingAlgorithm::createInstance()
(However for a different sub-class implemented in C++ then it would be the first time it was seen
by Python so the /Factory/ on create() would be correct.)

You might try using /TransferBack/ on create() instead - that might be the best compromise.
"

(cherry picked from commit da59316)

python/core/auto_generated/layout/qgslayoutitemregistry.sip.in

@@ -58,7 +58,8 @@ Returns a translated, user visible name for plurals of the layout item class (e.
 .. versionadded:: 3.10
 %End
 
-    virtual QgsLayoutItem *createItem( QgsLayout *layout ) = 0 /Factory/;
+
+    virtual QgsLayoutItem *createItem( QgsLayout *layout ) = 0 /TransferBack/;
 %Docstring
 Creates a layout item of this class for a specified ``layout``.
 %End
@@ -120,7 +121,8 @@ Returns an icon representing the layout multiframe type.
 Returns a translated, user visible name for the layout multiframe class.
 %End
 
-    virtual QgsLayoutMultiFrame *createMultiFrame( QgsLayout *layout ) = 0 /Factory/;
+
+    virtual QgsLayoutMultiFrame *createMultiFrame( QgsLayout *layout ) = 0 /TransferBack/;
 %Docstring
 Creates a layout multiframe of this class for a specified ``layout``.
 %End
@@ -233,6 +235,7 @@ a corresponding type was not found in the registry.
 .. seealso:: :py:func:`itemMetadata`
 %End
 
+
     bool addLayoutItemType( QgsLayoutItemAbstractMetadata *metadata /Transfer/ );
 %Docstring
 Registers a new layout item type. Takes ownership of the metadata instance.
@@ -247,14 +250,14 @@ Registers a new layout multiframe type. Takes ownership of the metadata instance
 .. seealso:: :py:func:`addLayoutItemType`
 %End
 
-    QgsLayoutItem *createItem( int type, QgsLayout *layout ) const /Factory/;
+    QgsLayoutItem *createItem( int type, QgsLayout *layout ) const /TransferBack/;
 %Docstring
 Creates a new instance of a layout item given the item ``type``, and target ``layout``.
 
 .. seealso:: :py:func:`createMultiFrame`
 %End
 
-    QgsLayoutMultiFrame *createMultiFrame( int type, QgsLayout *layout ) const /Factory/;
+    QgsLayoutMultiFrame *createMultiFrame( int type, QgsLayout *layout ) const /TransferBack/;
 %Docstring
 Creates a new instance of a layout multiframe given the multiframe ``type``, and target ``layout``.
 

python/gui/auto_generated/layout/qgslayoutitemguiregistry.sip.in

@@ -79,28 +79,29 @@ Returns a translated, user visible name identifying the corresponding layout ite
 Returns an icon representing creation of the layout item type.
 %End
 
-    virtual QgsLayoutItemBaseWidget *createItemWidget( QgsLayoutItem *item ) /Factory/;
+
+    virtual QgsLayoutItemBaseWidget *createItemWidget( QgsLayoutItem *item ) /TransferBack/;
 %Docstring
 Creates a configuration widget for an ``item`` of this type. Can return ``None`` if no configuration GUI is required.
 %End
 
-    virtual QgsLayoutViewRubberBand *createRubberBand( QgsLayoutView *view ) /Factory/;
+    virtual QgsLayoutViewRubberBand *createRubberBand( QgsLayoutView *view ) /TransferBack/;
 %Docstring
 Creates a rubber band for use when creating layout items of this type. Can return ``None`` if no rubber band
 should be created. The default behavior is to create a rectangular rubber band.
 
 .. seealso:: :py:func:`createNodeRubberBand`
 %End
 
-    virtual QAbstractGraphicsShapeItem *createNodeRubberBand( QgsLayoutView *view ) /Factory/;
+    virtual QAbstractGraphicsShapeItem *createNodeRubberBand( QgsLayoutView *view ) /TransferBack/;
 %Docstring
 Creates a rubber band for use when creating layout node based items of this type. Can return ``None`` if no rubber band
 should be created. The default behavior is to return ``None``.
 
 .. seealso:: :py:func:`createRubberBand`
 %End
 
-    virtual QgsLayoutItem *createItem( QgsLayout *layout ) /Factory/;
+    virtual QgsLayoutItem *createItem( QgsLayout *layout ) /TransferBack/;
 %Docstring
 Creates an instance of the corresponding item type.
 %End
@@ -212,7 +213,8 @@ Returns a reference to the item group with matching ``id``.
 .. seealso:: :py:func:`addItemGroup`
 %End
 
-    QgsLayoutItem *createItem( int metadataId, QgsLayout *layout ) const /Factory/;
+
+    QgsLayoutItem *createItem( int metadataId, QgsLayout *layout ) const /TransferBack/;
 %Docstring
 Creates a new instance of a layout item given the item metadata ``metadataId``, target ``layout``.
 %End
@@ -225,7 +227,8 @@ This is only called for additions which result from GUI operations - i.e. it is
 called for items added from templates.
 %End
 
-    QgsLayoutItemBaseWidget *createItemWidget( QgsLayoutItem *item ) const /Factory/;
+
+    QgsLayoutItemBaseWidget *createItemWidget( QgsLayoutItem *item ) const /TransferBack/;
 %Docstring
 Creates a new instance of a layout item configuration widget for the specified ``item``.
 %End

src/core/layout/qgslayoutitemregistry.h

@@ -77,10 +77,25 @@ class CORE_EXPORT QgsLayoutItemAbstractMetadata
      */
     QString visiblePluralName() const { return mVisibleNamePlural; }
 
+    /*
+     * IMPORTANT: While it seems like /Factory/ would be the correct annotations here, that's not
+     * the case.
+     * As per Phil Thomson's advice on https://www.riverbankcomputing.com/pipermail/pyqt/2017-July/039450.html:
+     *
+     * "
+     * /Factory/ is used when the instance returned is guaranteed to be new to Python.
+     * In this case it isn't because it has already been seen when being returned by QgsProcessingAlgorithm::createInstance()
+     * (However for a different sub-class implemented in C++ then it would be the first time it was seen
+     * by Python so the /Factory/ on create() would be correct.)
+     *
+     * You might try using /TransferBack/ on create() instead - that might be the best compromise.
+     * "
+     */
+
     /**
      * Creates a layout item of this class for a specified \a layout.
      */
-    virtual QgsLayoutItem *createItem( QgsLayout *layout ) = 0 SIP_FACTORY;
+    virtual QgsLayoutItem *createItem( QgsLayout *layout ) = 0 SIP_TRANSFERBACK;
 
     /**
      * Resolve paths in the item's \a properties (if there are any paths).
@@ -201,10 +216,25 @@ class CORE_EXPORT QgsLayoutMultiFrameAbstractMetadata
      */
     QString visibleName() const { return mVisibleName; }
 
+    /*
+     * IMPORTANT: While it seems like /Factory/ would be the correct annotations here, that's not
+     * the case.
+     * As per Phil Thomson's advice on https://www.riverbankcomputing.com/pipermail/pyqt/2017-July/039450.html:
+     *
+     * "
+     * /Factory/ is used when the instance returned is guaranteed to be new to Python.
+     * In this case it isn't because it has already been seen when being returned by QgsProcessingAlgorithm::createInstance()
+     * (However for a different sub-class implemented in C++ then it would be the first time it was seen
+     * by Python so the /Factory/ on create() would be correct.)
+     *
+     * You might try using /TransferBack/ on create() instead - that might be the best compromise.
+     * "
+     */
+
     /**
      * Creates a layout multiframe of this class for a specified \a layout.
      */
-    virtual QgsLayoutMultiFrame *createMultiFrame( QgsLayout *layout ) = 0 SIP_FACTORY;
+    virtual QgsLayoutMultiFrame *createMultiFrame( QgsLayout *layout ) = 0 SIP_TRANSFERBACK;
 
     /**
      * Resolve paths in the item's \a properties (if there are any paths).
@@ -379,6 +409,21 @@ class CORE_EXPORT QgsLayoutItemRegistry : public QObject
      */
     QgsLayoutMultiFrameAbstractMetadata *multiFrameMetadata( int type ) const;
 
+    /*
+     * IMPORTANT: While it seems like /Factory/ would be the correct annotations here, that's not
+     * the case.
+     * As per Phil Thomson's advice on https://www.riverbankcomputing.com/pipermail/pyqt/2017-July/039450.html:
+     *
+     * "
+     * /Factory/ is used when the instance returned is guaranteed to be new to Python.
+     * In this case it isn't because it has already been seen when being returned by QgsProcessingAlgorithm::createInstance()
+     * (However for a different sub-class implemented in C++ then it would be the first time it was seen
+     * by Python so the /Factory/ on create() would be correct.)
+     *
+     * You might try using /TransferBack/ on create() instead - that might be the best compromise.
+     * "
+     */
+
     /**
      * Registers a new layout item type. Takes ownership of the metadata instance.
      * \see addLayoutMultiFrameType()
@@ -395,13 +440,13 @@ class CORE_EXPORT QgsLayoutItemRegistry : public QObject
      * Creates a new instance of a layout item given the item \a type, and target \a layout.
      * \see createMultiFrame()
      */
-    QgsLayoutItem *createItem( int type, QgsLayout *layout ) const SIP_FACTORY;
+    QgsLayoutItem *createItem( int type, QgsLayout *layout ) const SIP_TRANSFERBACK;
 
     /**
      * Creates a new instance of a layout multiframe given the multiframe \a type, and target \a layout.
      * \see createItem()
      */
-    QgsLayoutMultiFrame *createMultiFrame( int type, QgsLayout *layout ) const SIP_FACTORY;
+    QgsLayoutMultiFrame *createMultiFrame( int type, QgsLayout *layout ) const SIP_TRANSFERBACK;
 
     /**
      * Resolve paths in properties of a particular symbol layer.

src/core/layout/qgslayoutitemundocommand.h

@@ -70,7 +70,7 @@ class CORE_EXPORT QgsLayoutItemUndoCommand: public QgsAbstractLayoutUndoCommand
     void saveState( QDomDocument &stateDoc ) const override;
     void restoreState( QDomDocument &stateDoc ) override;
 
-    virtual QgsLayoutItem *recreateItem( int itemType, QgsLayout *layout ) SIP_FACTORY;
+    virtual QgsLayoutItem *recreateItem( int itemType, QgsLayout *layout );
 
   private:
 

src/gui/layout/qgslayoutitemguiregistry.h

@@ -103,29 +103,44 @@ class GUI_EXPORT QgsLayoutItemAbstractGuiMetadata
      */
     virtual QIcon creationIcon() const { return QgsApplication::getThemeIcon( QStringLiteral( "/mActionAddBasicRectangle.svg" ) ); }
 
+    /*
+     * IMPORTANT: While it seems like /Factory/ would be the correct annotations here, that's not
+     * the case.
+     * As per Phil Thomson's advice on https://www.riverbankcomputing.com/pipermail/pyqt/2017-July/039450.html:
+     *
+     * "
+     * /Factory/ is used when the instance returned is guaranteed to be new to Python.
+     * In this case it isn't because it has already been seen when being returned by QgsProcessingAlgorithm::createInstance()
+     * (However for a different sub-class implemented in C++ then it would be the first time it was seen
+     * by Python so the /Factory/ on create() would be correct.)
+     *
+     * You might try using /TransferBack/ on create() instead - that might be the best compromise.
+     * "
+     */
+
     /**
      * Creates a configuration widget for an \a item of this type. Can return NULLPTR if no configuration GUI is required.
      */
-    virtual QgsLayoutItemBaseWidget *createItemWidget( QgsLayoutItem *item ) SIP_FACTORY { Q_UNUSED( item ) return nullptr; }
+    virtual QgsLayoutItemBaseWidget *createItemWidget( QgsLayoutItem *item ) SIP_TRANSFERBACK { Q_UNUSED( item ) return nullptr; }
 
     /**
      * Creates a rubber band for use when creating layout items of this type. Can return NULLPTR if no rubber band
      * should be created. The default behavior is to create a rectangular rubber band.
      * \see createNodeRubberBand()
      */
-    virtual QgsLayoutViewRubberBand *createRubberBand( QgsLayoutView *view ) SIP_FACTORY;
+    virtual QgsLayoutViewRubberBand *createRubberBand( QgsLayoutView *view ) SIP_TRANSFERBACK;
 
     /**
      * Creates a rubber band for use when creating layout node based items of this type. Can return NULLPTR if no rubber band
      * should be created. The default behavior is to return NULLPTR.
      * \see createRubberBand()
      */
-    virtual QAbstractGraphicsShapeItem *createNodeRubberBand( QgsLayoutView *view ) SIP_FACTORY;
+    virtual QAbstractGraphicsShapeItem *createNodeRubberBand( QgsLayoutView *view ) SIP_TRANSFERBACK;
 
     /**
      * Creates an instance of the corresponding item type.
      */
-    virtual QgsLayoutItem *createItem( QgsLayout *layout ) SIP_FACTORY;
+    virtual QgsLayoutItem *createItem( QgsLayout *layout ) SIP_TRANSFERBACK;
 
     /**
      * Called when a newly created item of the associated type has been added to a layout.
@@ -377,10 +392,25 @@ class GUI_EXPORT QgsLayoutItemGuiRegistry : public QObject
      */
     const QgsLayoutItemGuiGroup &itemGroup( const QString &id );
 
+    /*
+     * IMPORTANT: While it seems like /Factory/ would be the correct annotations here, that's not
+     * the case.
+     * As per Phil Thomson's advice on https://www.riverbankcomputing.com/pipermail/pyqt/2017-July/039450.html:
+     *
+     * "
+     * /Factory/ is used when the instance returned is guaranteed to be new to Python.
+     * In this case it isn't because it has already been seen when being returned by QgsProcessingAlgorithm::createInstance()
+     * (However for a different sub-class implemented in C++ then it would be the first time it was seen
+     * by Python so the /Factory/ on create() would be correct.)
+     *
+     * You might try using /TransferBack/ on create() instead - that might be the best compromise.
+     * "
+     */
+
     /**
      * Creates a new instance of a layout item given the item metadata \a metadataId, target \a layout.
      */
-    QgsLayoutItem *createItem( int metadataId, QgsLayout *layout ) const SIP_FACTORY;
+    QgsLayoutItem *createItem( int metadataId, QgsLayout *layout ) const SIP_TRANSFERBACK;
 
     /**
      * Called when a newly created item of the associated metadata \a metadataId has been added to a layout.
@@ -390,10 +420,25 @@ class GUI_EXPORT QgsLayoutItemGuiRegistry : public QObject
      */
     void newItemAddedToLayout( int metadataId, QgsLayoutItem *item );
 
+    /*
+     * IMPORTANT: While it seems like /Factory/ would be the correct annotations here, that's not
+     * the case.
+     * As per Phil Thomson's advice on https://www.riverbankcomputing.com/pipermail/pyqt/2017-July/039450.html:
+     *
+     * "
+     * /Factory/ is used when the instance returned is guaranteed to be new to Python.
+     * In this case it isn't because it has already been seen when being returned by QgsProcessingAlgorithm::createInstance()
+     * (However for a different sub-class implemented in C++ then it would be the first time it was seen
+     * by Python so the /Factory/ on create() would be correct.)
+     *
+     * You might try using /TransferBack/ on create() instead - that might be the best compromise.
+     * "
+     */
+
     /**
      * Creates a new instance of a layout item configuration widget for the specified \a item.
      */
-    QgsLayoutItemBaseWidget *createItemWidget( QgsLayoutItem *item ) const SIP_FACTORY;
+    QgsLayoutItemBaseWidget *createItemWidget( QgsLayoutItem *item ) const SIP_TRANSFERBACK;
 
     /**
      * Creates a new rubber band item for the specified item \a metadataId and destination \a view.