#13987 PDM: Add RicNewNestedCollectionFeature and RimcNestedCollectionBase

Generalise the per-domain "Add Folder" command and the scripting-side
add-folder method so they work against any container that exposes
caf::PdmNestedCollectionBase.

- RicNewNestedCollectionFeature: command feature that walks the
  selected PdmObject up to the nearest PdmNestedCollectionBase ancestor
  and calls addNewSubCollection(). Hidden via canAddSubCollection() for
  leaf containers.
- RimcNestedCollectionBase: scripting wrapper exposing the same
  add-sub-collection action through the Python interface, so generated
  Python bindings get the operation for free on every derived class.

Neither is wired to a concrete collection yet; the per-domain features
remain in place until the migration commit replaces them.

ApplicationLibCode/Commands/CMakeLists_files.cmake

@@ -106,6 +106,7 @@ set(SOURCE_GROUP_HEADER_FILES
     ${CMAKE_CURRENT_LIST_DIR}/RicImportGridAndSummaryEnsembleFeature.h
     ${CMAKE_CURRENT_LIST_DIR}/RicHistogramPlotTools.h
     ${CMAKE_CURRENT_LIST_DIR}/RicCreateGridStatisticsPlotFeature.h
+    ${CMAKE_CURRENT_LIST_DIR}/RicNewNestedCollectionFeature.h
 )
 
 set(SOURCE_GROUP_SOURCE_FILES
@@ -216,6 +217,7 @@ set(SOURCE_GROUP_SOURCE_FILES
     ${CMAKE_CURRENT_LIST_DIR}/RicImportGridAndSummaryEnsembleFeature.cpp
     ${CMAKE_CURRENT_LIST_DIR}/RicHistogramPlotTools.cpp
     ${CMAKE_CURRENT_LIST_DIR}/RicCreateGridStatisticsPlotFeature.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/RicNewNestedCollectionFeature.cpp
 )
 
 list(APPEND COMMAND_CODE_HEADER_FILES ${SOURCE_GROUP_HEADER_FILES})

ApplicationLibCode/Commands/RicNewNestedCollectionFeature.cpp

@@ -0,0 +1,77 @@
+/////////////////////////////////////////////////////////////////////////////////
+//
+//  Copyright (C) 2026     Equinor ASA
+//
+//  ResInsight 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 3 of the License, or
+//  (at your option) any later version.
+//
+//  ResInsight is distributed in the hope that it will be useful, but WITHOUT ANY
+//  WARRANTY; without even the implied warranty of MERCHANTABILITY or
+//  FITNESS FOR A PARTICULAR PURPOSE.
+//
+//  See the GNU General Public License at <http://www.gnu.org/licenses/gpl.html>
+//  for more details.
+//
+/////////////////////////////////////////////////////////////////////////////////
+
+#include "RicNewNestedCollectionFeature.h"
+
+#include "Riu3DMainWindowTools.h"
+
+#include "cafPdmNestedCollectionBase.h"
+#include "cafPdmUiItem.h"
+#include "cafSelectionManager.h"
+
+#include <QAction>
+
+CAF_CMD_SOURCE_INIT( RicNewNestedCollectionFeature, "RicNewNestedCollectionFeature" );
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+static caf::PdmNestedCollectionBase* selectedNestedCollection()
+{
+    auto items = caf::SelectionManager::instance()->selectedItems();
+    for ( auto* item : items )
+    {
+        if ( auto* nested = dynamic_cast<caf::PdmNestedCollectionBase*>( item ) )
+        {
+            return nested;
+        }
+    }
+    return nullptr;
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+bool RicNewNestedCollectionFeature::isCommandEnabled() const
+{
+    auto* nested = selectedNestedCollection();
+    return nested != nullptr && nested->canAddSubCollection();
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+void RicNewNestedCollectionFeature::onActionTriggered( bool isChecked )
+{
+    auto* parent = selectedNestedCollection();
+    if ( !parent || !parent->canAddSubCollection() ) return;
+
+    caf::PdmObject* added = parent->addNewSubCollection();
+    if ( !added ) return;
+
+    Riu3DMainWindowTools::selectAsCurrentItem( added );
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+void RicNewNestedCollectionFeature::setupActionLook( QAction* actionToSetup )
+{
+    actionToSetup->setText( "Add Folder" );
+    actionToSetup->setIcon( QIcon( ":/Folder.png" ) );
+}

ApplicationLibCode/Commands/RicNewNestedCollectionFeature.h

@@ -0,0 +1,37 @@
+/////////////////////////////////////////////////////////////////////////////////
+//
+//  Copyright (C) 2026     Equinor ASA
+//
+//  ResInsight 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 3 of the License, or
+//  (at your option) any later version.
+//
+//  ResInsight is distributed in the hope that it will be useful, but WITHOUT ANY
+//  WARRANTY; without even the implied warranty of MERCHANTABILITY or
+//  FITNESS FOR A PARTICULAR PURPOSE.
+//
+//  See the GNU General Public License at <http://www.gnu.org/licenses/gpl.html>
+//  for more details.
+//
+/////////////////////////////////////////////////////////////////////////////////
+
+#pragma once
+
+#include "cafCmdFeature.h"
+
+//==================================================================================================
+///
+/// Adds a new subcollection ("folder") to the selected caf::PdmNestedCollection-derived object.
+/// Works with any nested collection type via caf::PdmNestedCollectionBase.
+///
+//==================================================================================================
+class RicNewNestedCollectionFeature : public caf::CmdFeature
+{
+    CAF_CMD_HEADER_INIT;
+
+private:
+    bool isCommandEnabled() const override;
+    void onActionTriggered( bool isChecked ) override;
+    void setupActionLook( QAction* actionToSetup ) override;
+};

ApplicationLibCode/ProjectDataModelCommands/CMakeLists_files.cmake

@@ -40,6 +40,7 @@ set(SOURCE_GROUP_HEADER_FILES
     ${CMAKE_CURRENT_LIST_DIR}/RimcWellPathValve.h
     ${CMAKE_CURRENT_LIST_DIR}/RimcWellEventTimeline.h
     ${CMAKE_CURRENT_LIST_DIR}/RimcColorLegend.h
+    ${CMAKE_CURRENT_LIST_DIR}/RimcNestedCollectionBase.h
 )
 
 set(SOURCE_GROUP_SOURCE_FILES
@@ -84,6 +85,7 @@ set(SOURCE_GROUP_SOURCE_FILES
     ${CMAKE_CURRENT_LIST_DIR}/RimcWellPathValve.cpp
     ${CMAKE_CURRENT_LIST_DIR}/RimcWellEventTimeline.cpp
     ${CMAKE_CURRENT_LIST_DIR}/RimcColorLegend.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/RimcNestedCollectionBase.cpp
 )
 
 list(APPEND CODE_HEADER_FILES ${SOURCE_GROUP_HEADER_FILES})

ApplicationLibCode/ProjectDataModelCommands/RimcNestedCollectionBase.cpp

@@ -0,0 +1,73 @@
+/////////////////////////////////////////////////////////////////////////////////
+//
+//  Copyright (C) 2026     Equinor ASA
+//
+//  ResInsight 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 3 of the License, or
+//  (at your option) any later version.
+//
+//  ResInsight is distributed in the hope that it will be useful, but WITHOUT ANY
+//  WARRANTY; without even the implied warranty of MERCHANTABILITY or
+//  FITNESS FOR A PARTICULAR PURPOSE.
+//
+//  See the GNU General Public License at <http://www.gnu.org/licenses/gpl.html>
+//  for more details.
+//
+/////////////////////////////////////////////////////////////////////////////////
+
+#include "RimcNestedCollectionBase.h"
+
+#include "cafPdmFieldScriptingCapability.h"
+#include "cafPdmNestedCollectionBase.h"
+
+CAF_PDM_OBJECT_METHOD_SOURCE_INIT( caf::PdmNestedCollectionBase, RimcNestedCollectionBase, "AddFolder" );
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+RimcNestedCollectionBase::RimcNestedCollectionBase( caf::PdmObjectHandle* self )
+    : caf::PdmObjectCreationMethod( self )
+{
+    CAF_PDM_InitObject( "Add Folder", "", "", "Add a new folder" );
+
+    CAF_PDM_InitScriptableField( &m_folderName, "FolderName", QString( "Folder" ), "", "", "", "New folder name" );
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+std::expected<caf::PdmObjectHandle*, QString> RimcNestedCollectionBase::execute()
+{
+    auto* coll = self<caf::PdmNestedCollectionBase>();
+    if ( !coll || !coll->canAddSubCollection() )
+    {
+        return std::unexpected<QString>( QString( "Cannot add subfolder" ) );
+    }
+
+    caf::PdmObject* added = coll->addNewSubCollection();
+    if ( !added )
+    {
+        return std::unexpected<QString>( QString( "Failed to add subfolder" ) );
+    }
+
+    if ( auto* asNested = dynamic_cast<caf::PdmNestedCollectionBase*>( added ) )
+    {
+        asNested->setCollectionName( m_folderName() );
+    }
+    coll->uiCapability()->updateConnectedEditors();
+    return added;
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+QString RimcNestedCollectionBase::classKeywordReturnedType() const
+{
+    // Returned at codegen time. The Python generator emits AddFolder on the
+    // PdmNestedCollectionBase Python class (since that is where the method is registered),
+    // so the declared return type must be stable across all concrete nested collections.
+    // The actual runtime instance is whatever the concrete addNewSubCollection() returns;
+    // callers can use descendants() / class_from_keyword to recover the precise type.
+    return caf::PdmNestedCollectionBase::classKeywordStatic();
+}

ApplicationLibCode/ProjectDataModelCommands/RimcNestedCollectionBase.h

@@ -0,0 +1,46 @@
+/////////////////////////////////////////////////////////////////////////////////
+//
+//  Copyright (C) 2026     Equinor ASA
+//
+//  ResInsight 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 3 of the License, or
+//  (at your option) any later version.
+//
+//  ResInsight is distributed in the hope that it will be useful, but WITHOUT ANY
+//  WARRANTY; without even the implied warranty of MERCHANTABILITY or
+//  FITNESS FOR A PARTICULAR PURPOSE.
+//
+//  See the GNU General Public License at <http://www.gnu.org/licenses/gpl.html>
+//  for more details.
+//
+/////////////////////////////////////////////////////////////////////////////////
+
+#pragma once
+
+#include "cafPdmField.h"
+#include "cafPdmObjectHandle.h"
+#include "cafPdmObjectMethod.h"
+
+#include <QString>
+
+//==================================================================================================
+///
+/// Generic "Add Folder" script method registered once against caf::PdmNestedCollectionBase.
+/// Every concrete nested collection inherits the method through the CAF method-factory
+/// inheritance walk, so derived classes do not need their own AddFolder counterpart.
+///
+//==================================================================================================
+class RimcNestedCollectionBase : public caf::PdmObjectCreationMethod
+{
+    CAF_PDM_HEADER_INIT;
+
+public:
+    RimcNestedCollectionBase( caf::PdmObjectHandle* self );
+
+    std::expected<caf::PdmObjectHandle*, QString> execute() override;
+    QString                                       classKeywordReturnedType() const override;
+
+private:
+    caf::PdmField<QString> m_folderName;
+};