From baff9dd8a63819250f3421229d1716b472a30e5b Mon Sep 17 00:00:00 2001
From: Dalai Felinto <dalai@blender.org>
Date: Wed, 24 Sep 2025 09:58:30 +0200
Subject: [PATCH] VSE: Story Tools: Scene Asset behaviour: always add a new
 scene

* If the asset was local to the file, creates a copy of it.
* If the asset was from an external asset library makes sure it is appended.

Design ref: #145522

Pull Request: https://projects.blender.org/blender/blender/pulls/146657
---
 source/blender/editors/asset/ED_asset_import.hh  |  8 +++++++-
 .../blender/editors/asset/intern/asset_import.cc | 16 ++++++++++++++--
 .../editors/space_sequencer/sequencer_add.cc     | 12 +++++++++++-
 3 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/source/blender/editors/asset/ED_asset_import.hh b/source/blender/editors/asset/ED_asset_import.hh
index 8c4d634aea7..4f329e5daa3 100644
--- a/source/blender/editors/asset/ED_asset_import.hh
+++ b/source/blender/editors/asset/ED_asset_import.hh
@@ -19,7 +19,13 @@ namespace blender::ed::asset {
 /**
  * If the asset already has a corresponding local #ID, return it. Otherwise, link or append the
  * asset's data-block, using "Append & Reuse" if the method is unspecified.
+ *
+ * \param import_method: Overrides library's default importing method.
+ * If not set and the library has no default, #ASSET_IMPORT_APPEND_REUSE will be used.
  */
-ID *asset_local_id_ensure_imported(Main &bmain, const asset_system::AssetRepresentation &asset);
+ID *asset_local_id_ensure_imported(
+    Main &bmain,
+    const asset_system::AssetRepresentation &asset,
+    const std::optional<eAssetImportMethod> import_method = std::nullopt);
 
 }  // namespace blender::ed::asset
diff --git a/source/blender/editors/asset/intern/asset_import.cc b/source/blender/editors/asset/intern/asset_import.cc
index a2b62d0b289..4a9380469ac 100644
--- a/source/blender/editors/asset/intern/asset_import.cc
+++ b/source/blender/editors/asset/intern/asset_import.cc
@@ -18,7 +18,9 @@
 
 namespace blender::ed::asset {
 
-ID *asset_local_id_ensure_imported(Main &bmain, const asset_system::AssetRepresentation &asset)
+ID *asset_local_id_ensure_imported(Main &bmain,
+                                   const asset_system::AssetRepresentation &asset,
+                                   const std::optional<eAssetImportMethod> import_method)
 {
   if (ID *local_id = asset.local_id()) {
     return local_id;
@@ -29,7 +31,17 @@ ID *asset_local_id_ensure_imported(Main &bmain, const asset_system::AssetReprese
     return nullptr;
   }
 
-  switch (asset.get_import_method().value_or(ASSET_IMPORT_APPEND_REUSE)) {
+  const eAssetImportMethod method = [&]() {
+    if (import_method) {
+      return *import_method;
+    }
+    if (std::optional asset_method = asset.get_import_method()) {
+      return *asset_method;
+    }
+    return ASSET_IMPORT_APPEND_REUSE;
+  }();
+
+  switch (method) {
     case ASSET_IMPORT_LINK:
       return WM_file_link_datablock(&bmain,
                                     nullptr,
diff --git a/source/blender/editors/space_sequencer/sequencer_add.cc b/source/blender/editors/space_sequencer/sequencer_add.cc
index b40efbe2daf..33532dc75ac 100644
--- a/source/blender/editors/space_sequencer/sequencer_add.cc
+++ b/source/blender/editors/space_sequencer/sequencer_add.cc
@@ -793,13 +793,23 @@ void SEQUENCER_OT_scene_strip_add_new(wmOperatorType *ot)
 /** \name Add Scene Strip From Scene Asset
  * \{ */
 
+/**
+ * Make sure the scene is always unique and ready to edit.
+ * If it was local it should be duplicated. If external it should be appended.
+ */
 static Scene *sequencer_add_scene_asset(const bContext &C,
                                         const asset_system::AssetRepresentation &asset,
                                         ReportList & /*reports*/)
 {
   Main &bmain = *CTX_data_main(&C);
   Scene *scene_asset = reinterpret_cast<Scene *>(
-      asset::asset_local_id_ensure_imported(bmain, asset));
+      asset::asset_local_id_ensure_imported(bmain, asset, ASSET_IMPORT_APPEND));
+
+  if (asset.is_local_id()) {
+    /* Local scene that needs to be duplicated. */
+    Scene *scene_copy = BKE_scene_duplicate(&bmain, scene_asset, SCE_COPY_FULL);
+    return scene_copy;
+  }
   return scene_asset;
 }