[elevation Profile] Correctly add a layer generated by a processing

python/PyQt6/core/auto_generated/layertree/qgslayertreeregistrybridge.sip.in

@@ -66,6 +66,13 @@ Set where the new layers should be inserted - can be used to follow current sele
 By default it is root group with zero index.
 
 .. versionadded:: 3.10
+%End
+
+    InsertionPoint layerInsertionPoint() const;
+%Docstring
+Returns the insertion point used to add layers to the tree
+
+.. versionadded:: 3.42
 %End
 
     void setLayerInsertionMethod( Qgis::LayerTreeInsertionMethod method );

python/core/auto_generated/layertree/qgslayertreeregistrybridge.sip.in

@@ -66,6 +66,13 @@ Set where the new layers should be inserted - can be used to follow current sele
 By default it is root group with zero index.
 
 .. versionadded:: 3.10
+%End
+
+    InsertionPoint layerInsertionPoint() const;
+%Docstring
+Returns the insertion point used to add layers to the tree
+
+.. versionadded:: 3.42
 %End
 
     void setLayerInsertionMethod( Qgis::LayerTreeInsertionMethod method );

python/plugins/processing/gui/Postprocessing.py

@@ -35,6 +35,7 @@
     QgsLayerTreeLayer,
     QgsLayerTreeGroup,
     QgsLayerTreeNode,
+    QgsLayerTreeRegistryBridge,
 )
 from qgis.utils import iface
 
@@ -237,8 +238,6 @@ def handleAlgorithmResults(
                 # output layer already exists in the destination project
                 owned_map_layer = context.temporaryLayerStore().takeMapLayer(layer)
                 if owned_map_layer:
-                    details.project.addMapLayer(owned_map_layer, False)
-
                     # we don't add the layer to the tree yet -- that's done
                     # later, after we've sorted all added layers
                     layer_tree_layer = create_layer_tree_layer(owned_map_layer, details)
@@ -277,10 +276,15 @@ def handleAlgorithmResults(
         current_selected_node = iface.layerTreeView().currentNode()
         iface.layerTreeView().setUpdatesEnabled(False)
 
+    # store the current intersection point to restore it later
+    previous_insertion_point = (
+        details.project.layerTreeRegistryBridge().layerInsertionPoint()
+    )
     for group, layer_node in sorted_layer_tree_layers:
         layer_node.removeCustomProperty(SORT_ORDER_CUSTOM_PROPERTY)
+        insertion_point: Optional[QgsLayerTreeRegistryBridge.InsertionPoint] = None
         if group is not None:
-            group.insertChildNode(0, layer_node)
+            insertion_point = QgsLayerTreeRegistryBridge.InsertionPoint(group, 0)
         else:
             # no destination group for this layer, so should be placed
             # above the current layer
@@ -289,16 +293,32 @@ def handleAlgorithmResults(
                 current_node_index = current_node_group.children().index(
                     current_selected_node
                 )
-                current_node_group.insertChildNode(current_node_index, layer_node)
+                insertion_point = QgsLayerTreeRegistryBridge.InsertionPoint(
+                    current_node_group, current_node_index
+                )
             elif isinstance(current_selected_node, QgsLayerTreeGroup):
-                current_selected_node.insertChildNode(0, layer_node)
+                insertion_point = QgsLayerTreeRegistryBridge.InsertionPoint(
+                    current_selected_node, 0
+                )
             elif context.project():
-                context.project().layerTreeRoot().insertChildNode(0, layer_node)
+                insertion_point = QgsLayerTreeRegistryBridge.InsertionPoint()
+
+        if insertion_point:
+            details.project.layerTreeRegistryBridge().setLayerInsertionPoint(
+                insertion_point
+            )
+
+        details.project.addMapLayer(layer_node.layer())
 
         if not have_set_active_layer and iface is not None:
             iface.setActiveLayer(layer_node.layer())
             have_set_active_layer = True
 
+    # reset to the previous insertion point
+    details.project.layerTreeRegistryBridge().setLayerInsertionPoint(
+        previous_insertion_point
+    )
+
     # all layers have been added to the layer tree, so safe to call
     # postProcessors now
     for layer, details in layers_to_post_process:

src/core/layertree/qgslayertreeregistrybridge.cpp

@@ -49,6 +49,12 @@ void QgsLayerTreeRegistryBridge::setLayerInsertionPoint( const InsertionPoint &i
   mInsertionPointPosition = insertionPoint.position;
 }
 
+QgsLayerTreeRegistryBridge::InsertionPoint QgsLayerTreeRegistryBridge::layerInsertionPoint() const
+{
+  QgsLayerTreeGroup *group = mInsertionPointGroup.isNull() ? mRoot : mInsertionPointGroup.data();
+  return InsertionPoint( group, mInsertionPointPosition );
+}
+
 void QgsLayerTreeRegistryBridge::layersAdded( const QList<QgsMapLayer *> &layers )
 {
   if ( !mEnabled )

src/core/layertree/qgslayertreeregistrybridge.h

@@ -85,6 +85,12 @@ class CORE_EXPORT QgsLayerTreeRegistryBridge : public QObject
      */
     void setLayerInsertionPoint( const InsertionPoint &insertionPoint );
 
+    /**
+     * Returns the insertion point used to add layers to the tree
+     * \since QGIS 3.42
+     */
+    InsertionPoint layerInsertionPoint() const;
+
     /**
      * Sets the insertion \a method used to add layers to the tree
      * \since QGIS 3.30

tests/src/python/CMakeLists.txt

@@ -127,6 +127,7 @@ ADD_PYTHON_TEST(PyQgsLayerMetadataProviderPython test_qgslayermetadataprovider_p
 ADD_PYTHON_TEST(PyQgsLayerMetadataProviderOgr test_qgslayermetadataprovider_ogr.py)
 ADD_PYTHON_TEST(PyQgsLayerTree test_qgslayertree.py)
 ADD_PYTHON_TEST(PyQgsLayerTreeFilterProxyModel test_qgslayertreefilterproxymodel.py)
+ADD_PYTHON_TEST(PyQgsLayerTreeRegistryBridge test_qgslayertreeregistrybridge.py)
 ADD_PYTHON_TEST(PyQgsLayout test_qgslayout.py)
 ADD_PYTHON_TEST(PyQgsLayoutAlign test_qgslayoutaligner.py)
 ADD_PYTHON_TEST(PyQgsLayoutAtlas test_qgslayoutatlas.py)

tests/src/python/test_qgslayertreeregistrybridge.py

@@ -0,0 +1,62 @@
+"""QGIS Unit tests for QgsLayerTreeRegistryBridge
+
+.. note:: This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+"""
+
+__author__ = "Jean Felder"
+__date__ = "05/02/2025"
+__copyright__ = "Copyright 2025, The QGIS Project"
+
+from qgis.core import (
+    QgsLayerTreeRegistryBridge,
+    QgsLayerTree,
+    QgsProject,
+    QgsLayerTreeGroup,
+)
+
+import unittest
+from qgis.testing import start_app, QgisTestCase
+
+start_app()
+
+
+class TestQgsLayerTreeRegistryBridge(QgisTestCase):
+
+    def test_constructor(self):
+        project = QgsProject()
+        root_group = QgsLayerTree()
+        bridge = QgsLayerTreeRegistryBridge(root_group, project)
+
+        self.assertTrue(bridge.isEnabled())
+        self.assertTrue(bridge.newLayersVisible())
+        self.assertEqual(bridge.layerInsertionPoint().group, root_group)
+        self.assertEqual(bridge.layerInsertionPoint().position, 0)
+
+    def test_insertion_point(self):
+        project = QgsProject()
+        root_group = QgsLayerTree()
+        bridge = QgsLayerTreeRegistryBridge(root_group, project)
+
+        self.assertEqual(bridge.layerInsertionPoint().group, root_group)
+        self.assertEqual(bridge.layerInsertionPoint().position, 0)
+
+        group_node = QgsLayerTreeGroup()
+        root_group.addChildNode(group_node)
+        bridge.setLayerInsertionPoint(
+            QgsLayerTreeRegistryBridge.InsertionPoint(group_node, 4)
+        )
+        self.assertEqual(bridge.layerInsertionPoint().group, group_node)
+        self.assertEqual(bridge.layerInsertionPoint().position, 4)
+
+        bridge.setLayerInsertionPoint(
+            QgsLayerTreeRegistryBridge.InsertionPoint(root_group, 0)
+        )
+        self.assertEqual(bridge.layerInsertionPoint().group, root_group)
+        self.assertEqual(bridge.layerInsertionPoint().position, 0)
+
+
+if __name__ == "__main__":
+    unittest.main()