IDMAnagement: Add owner ID pointer to embedded ones.

Add a dedicated `owner_id` pointer to ID types that can be embedded
(Collections and NodeTrees), and modify slightly come code to make
handling those more safe and consistent.

This implements first part of T69169.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D15838

1 files changed, 6 insertions, 7 deletions

diff --git a/source/blender/editors/space_node/node_edit.cc b/source/blender/editors/space_node/node_edit.cc
index 5f92e514385..9167b96b76f 100644
--- a/source/blender/editors/space_node/node_edit.cc
+++ b/source/blender/editors/space_node/node_edit.cc
@@ -506,12 +506,12 @@ void ED_node_shader_default(const bContext *C, ID *id)
   }
   else if (ELEM(GS(id->name), ID_WO, ID_LA)) {
     /* Emission */
-    bNodeTree *ntree = ntreeAddTree(nullptr, "Shader Nodetree", ntreeType_Shader->idname);
+    bNodeTree *ntree = ntreeAddTreeEmbedded(
+        nullptr, id, "Shader Nodetree", ntreeType_Shader->idname);
     bNode *shader, *output;
 
     if (GS(id->name) == ID_WO) {
       World *world = (World *)id;
-      world->nodetree = ntree;
 
       shader = nodeAddStaticNode(nullptr, ntree, SH_NODE_BACKGROUND);
       output = nodeAddStaticNode(nullptr, ntree, SH_NODE_OUTPUT_WORLD);
@@ -525,9 +525,6 @@ void ED_node_shader_default(const bContext *C, ID *id)
       copy_v3_v3(((bNodeSocketValueRGBA *)color_sock->default_value)->value, &world->horr);
     }
     else {
-      Light *light = (Light *)id;
-      light->nodetree = ntree;
-
       shader = nodeAddStaticNode(nullptr, ntree, SH_NODE_EMISSION);
       output = nodeAddStaticNode(nullptr, ntree, SH_NODE_OUTPUT_LIGHT);
       nodeAddLink(ntree,
@@ -560,7 +557,8 @@ void ED_node_composit_default(const bContext *C, Scene *sce)
     return;
   }
 
-  sce->nodetree = ntreeAddTree(nullptr, "Compositing Nodetree", ntreeType_Composite->idname);
+  sce->nodetree = ntreeAddTreeEmbedded(
+      nullptr, &sce->id, "Compositing Nodetree", ntreeType_Composite->idname);
 
   sce->nodetree->chunksize = 256;
   sce->nodetree->edit_quality = NTREE_QUALITY_HIGH;
@@ -593,7 +591,8 @@ void ED_node_texture_default(const bContext *C, Tex *tex)
     return;
   }
 
-  tex->nodetree = ntreeAddTree(nullptr, "Texture Nodetree", ntreeType_Texture->idname);
+  tex->nodetree = ntreeAddTreeEmbedded(
+      nullptr, &tex->id, "Texture Nodetree", ntreeType_Texture->idname);
 
   bNode *out = nodeAddStaticNode(C, tex->nodetree, TEX_NODE_OUTPUT);
   out->locx = 300.0f;