11 files changed, 38 insertions, 8 deletions
diff --git a/source/blender/blenkernel/BKE_lib_id.h b/source/blender/blenkernel/BKE_lib_id.h
index fac5dc8c010..5de669cb620 100644
--- a/source/blender/blenkernel/BKE_lib_id.h
+++ b/source/blender/blenkernel/BKE_lib_id.h
@@ -201,6 +201,8 @@ enum {
 void BKE_libblock_free_datablock(struct ID *id, const int flag) ATTR_NONNULL();
 void BKE_libblock_free_data(struct ID *id, const bool do_id_user) ATTR_NONNULL();
 
+void BKE_libblock_free_data_py(struct ID *id);
+
 void BKE_id_free_ex(struct Main *bmain, void *idv, int flag, const bool use_flag_from_idtag);
 void BKE_id_free(struct Main *bmain, void *idv);
 
diff --git a/source/blender/blenkernel/intern/gpencil.c b/source/blender/blenkernel/intern/gpencil.c
index 38397f8f307..f566e18fb2f 100644
--- a/source/blender/blenkernel/intern/gpencil.c
+++ b/source/blender/blenkernel/intern/gpencil.c
@@ -521,6 +521,7 @@ void BKE_gpencil_eval_delete(bGPdata *gpd_eval)
 {
   BKE_gpencil_free(gpd_eval, true);
   BKE_libblock_free_data(&gpd_eval->id, false);
+  BLI_assert(!gpd_eval->id.py_instance); /* Or call #BKE_libblock_free_data_py. */
   MEM_freeN(gpd_eval);
 }
 
diff --git a/source/blender/blenkernel/intern/lib_id_delete.c b/source/blender/blenkernel/intern/lib_id_delete.c
index a9407860c06..43afac5a376 100644
--- a/source/blender/blenkernel/intern/lib_id_delete.c
+++ b/source/blender/blenkernel/intern/lib_id_delete.c
@@ -142,14 +142,7 @@ void BKE_id_free_ex(Main *bmain, void *idv, int flag, const bool use_flag_from_i
     DEG_id_type_tag(bmain, type);
   }
 
-#ifdef WITH_PYTHON
-#  ifdef WITH_PYTHON_SAFETY
-  BPY_id_release(id);
-#  endif
-  if (id->py_instance) {
-    BPY_DECREF_RNA_INVALIDATE(id->py_instance);
-  }
-#endif
+  BKE_libblock_free_data_py(id);
 
   Key *key = ((flag & LIB_ID_FREE_NO_MAIN) == 0) ? BKE_key_from_id(id) : NULL;
 
@@ -406,3 +399,29 @@ size_t BKE_id_multi_tagged_delete(Main *bmain)
 {
   return id_delete(bmain, true);
 }
+
+/* -------------------------------------------------------------------- */
+/** \name Python Data Handling
+ * \{ */
+
+/**
+ * In most cases #BKE_id_free_ex handles this, when lower level functions are called directly
+ * this function will need to be called too, if Python has access to the data.
+ *
+ * ID data-blocks such as #Material.nodetree are not stored in #Main.
+ */
+void BKE_libblock_free_data_py(ID *id)
+{
+#ifdef WITH_PYTHON
+#  ifdef WITH_PYTHON_SAFETY
+  BPY_id_release(id);
+#  endif
+  if (id->py_instance) {
+    BPY_DECREF_RNA_INVALIDATE(id->py_instance);
+  }
+#else
+  UNUSED_VARS(id);
+#endif
+}
+
+/** \} */
diff --git a/source/blender/blenkernel/intern/material.c b/source/blender/blenkernel/intern/material.c
index 4f0b2a718ed..ca57038f1c4 100644
--- a/source/blender/blenkernel/intern/material.c
+++ b/source/blender/blenkernel/intern/material.c
@@ -1802,6 +1802,7 @@ void BKE_material_copybuf_free(void)
 {
   if (matcopybuf.nodetree) {
     ntreeFreeLocalTree(matcopybuf.nodetree);
+    BLI_assert(!matcopybuf.nodetree->id.py_instance); /* Or call #BKE_libblock_free_data_py. */
     MEM_freeN(matcopybuf.nodetree);
     matcopybuf.nodetree = NULL;
   }
diff --git a/source/blender/blenkernel/intern/node.cc b/source/blender/blenkernel/intern/node.cc
index 1bf95369794..bd22f049a8b 100644
--- a/source/blender/blenkernel/intern/node.cc
+++ b/source/blender/blenkernel/intern/node.cc
@@ -3194,6 +3194,7 @@ void ntreeFreeEmbeddedTree(bNodeTree *ntree)
 {
   ntreeFreeTree(ntree);
   BKE_libblock_free_data(&ntree->id, true);
+  BKE_libblock_free_data_py(&ntree->id);
 }
 
 void ntreeFreeLocalTree(bNodeTree *ntree)
diff --git a/source/blender/blenkernel/intern/particle_system.c b/source/blender/blenkernel/intern/particle_system.c
index f592b0f97ea..60edb78f8ba 100644
--- a/source/blender/blenkernel/intern/particle_system.c
+++ b/source/blender/blenkernel/intern/particle_system.c
@@ -4761,6 +4761,7 @@ static void particle_settings_free_local(ParticleSettings *particle_settings)
 {
   BKE_libblock_free_datablock(&particle_settings->id, 0);
   BKE_libblock_free_data(&particle_settings->id, false);
+  BLI_assert(!particle_settings->id.py_instance); /* Or call #BKE_libblock_free_data_py. */
   MEM_freeN(particle_settings);
 }
 
diff --git a/source/blender/blenkernel/intern/scene.c b/source/blender/blenkernel/intern/scene.c
index c55185c0f2a..5ecd9b7283e 100644
--- a/source/blender/blenkernel/intern/scene.c
+++ b/source/blender/blenkernel/intern/scene.c
@@ -446,6 +446,7 @@ static void scene_free_data(ID *id)
    * collections in the scene need to do it too? */
   if (scene->master_collection) {
     BKE_collection_free_data(scene->master_collection);
+    BKE_libblock_free_data_py(&scene->master_collection->id);
     MEM_freeN(scene->master_collection);
     scene->master_collection = NULL;
   }
diff --git a/source/blender/editors/space_clip/clip_editor.c b/source/blender/editors/space_clip/clip_editor.c
index 67b4fd61d38..834ef847069 100644
--- a/source/blender/editors/space_clip/clip_editor.c
+++ b/source/blender/editors/space_clip/clip_editor.c
@@ -1037,6 +1037,7 @@ static void prefetch_freejob(void *pjv)
   if (clip_local != NULL) {
     BKE_libblock_free_datablock(&clip_local->id, 0);
     BKE_libblock_free_data(&clip_local->id, false);
+    BLI_assert(!clip_local->id.py_instance); /* Or call #BKE_libblock_free_data_py. */
     MEM_freeN(clip_local);
   }
 
diff --git a/source/blender/gpu/intern/gpu_material.c b/source/blender/gpu/intern/gpu_material.c
index 37089785e0e..56e72fbeca9 100644
--- a/source/blender/gpu/intern/gpu_material.c
+++ b/source/blender/gpu/intern/gpu_material.c
@@ -758,6 +758,7 @@ GPUMaterial *GPU_material_from_nodetree(Scene *scene,
   /* Only free after GPU_pass_shader_get where GPUUniformBuf
    * read data from the local tree. */
   ntreeFreeLocalTree(localtree);
+  BLI_assert(!localtree->id.py_instance); /* Or call #BKE_libblock_free_data_py. */
   MEM_freeN(localtree);
 
   /* note that even if building the shader fails in some way, we still keep
diff --git a/source/blender/nodes/shader/node_shader_tree.c b/source/blender/nodes/shader/node_shader_tree.c
index 7367f73d171..98edc133a1d 100644
--- a/source/blender/nodes/shader/node_shader_tree.c
+++ b/source/blender/nodes/shader/node_shader_tree.c
@@ -531,6 +531,7 @@ static void ntree_shader_groups_flatten(bNodeTree *localtree)
       bNodeTree *ngroup = (bNodeTree *)node->id;
       ntreeFreeLocalNode(localtree, node);
       ntreeFreeTree(ngroup);
+      BLI_assert(!ngroup->id.py_instance); /* Or call #BKE_libblock_free_data_py. */
       MEM_freeN(ngroup);
     }
     else {
diff --git a/source/blender/windowmanager/intern/wm.c b/source/blender/windowmanager/intern/wm.c
index 9657f8aa03c..e11ef52eb84 100644
--- a/source/blender/windowmanager/intern/wm.c
+++ b/source/blender/windowmanager/intern/wm.c
@@ -628,6 +628,7 @@ void wm_close_and_free_all(bContext *C, ListBase *wmlist)
     wm_close_and_free(C, wm);
     BLI_remlink(wmlist, wm);
     BKE_libblock_free_data(&wm->id, true);
+    BKE_libblock_free_data_py(&wm->id);
     MEM_freeN(wm);
   }
 }