Merge branch 'blender-v2.83-release'

3 files changed, 34 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_lib_id.h b/source/blender/blenkernel/BKE_lib_id.h
index 9f36798fbd5..0c91ba6231b 100644
--- a/source/blender/blenkernel/BKE_lib_id.h
+++ b/source/blender/blenkernel/BKE_lib_id.h
@@ -74,6 +74,7 @@ void BKE_libblock_init_empty(struct ID *id) ATTR_NONNULL(1);
 
 void BKE_lib_libblock_session_uuid_reset(void);
 void BKE_lib_libblock_session_uuid_ensure(struct ID *id);
+void BKE_lib_libblock_session_uuid_renew(struct ID *id);
 
 void *BKE_id_new(struct Main *bmain, const short type, const char *name);
 void *BKE_id_new_nomain(const short type, const char *name);
diff --git a/source/blender/blenkernel/intern/blendfile.c b/source/blender/blenkernel/intern/blendfile.c
index 0d5d35e3508..13dcc7b06f6 100644
--- a/source/blender/blenkernel/intern/blendfile.c
+++ b/source/blender/blenkernel/intern/blendfile.c
@@ -201,6 +201,27 @@ static void setup_app_data(bContext *C,
     SWAP(ListBase, bmain->workspaces, bfd->main->workspaces);
     SWAP(ListBase, bmain->screens, bfd->main->screens);
 
+    /* In case of actual new file reading without loading UI, we need to regenerate the session
+     * uuid of the UI-related datablocks we are keeping from previous session, otherwise their uuid
+     * will collide with some generated for newly read data. */
+    if (mode != LOAD_UNDO) {
+      ID *id;
+      FOREACH_MAIN_LISTBASE_ID_BEGIN (&bfd->main->wm, id) {
+        BKE_lib_libblock_session_uuid_renew(id);
+      }
+      FOREACH_MAIN_LISTBASE_ID_END;
+
+      FOREACH_MAIN_LISTBASE_ID_BEGIN (&bfd->main->workspaces, id) {
+        BKE_lib_libblock_session_uuid_renew(id);
+      }
+      FOREACH_MAIN_LISTBASE_ID_END;
+
+      FOREACH_MAIN_LISTBASE_ID_BEGIN (&bfd->main->screens, id) {
+        BKE_lib_libblock_session_uuid_renew(id);
+      }
+      FOREACH_MAIN_LISTBASE_ID_END;
+    }
+
     /* we re-use current window and screen */
     win = CTX_wm_window(C);
     curscreen = CTX_wm_screen(C);
diff --git a/source/blender/blenkernel/intern/lib_id.c b/source/blender/blenkernel/intern/lib_id.c
index ad2cf078054..fe25016344e 100644
--- a/source/blender/blenkernel/intern/lib_id.c
+++ b/source/blender/blenkernel/intern/lib_id.c
@@ -1033,6 +1033,18 @@ void BKE_lib_libblock_session_uuid_ensure(ID *id)
 }
 
 /**
+ * Re-generate a new session-wise uuid for the given \a id.
+ *
+ * \warning This has a very specific use-case (to handle UI-related data-blocks that are kept
+ * across new file reading, when we do keep existing UI). No other usage is expected currently.
+ */
+void BKE_lib_libblock_session_uuid_renew(ID *id)
+{
+  id->session_uuid = MAIN_ID_SESSION_UUID_UNSET;
+  BKE_lib_libblock_session_uuid_ensure(id);
+}
+
+/**
  * Generic helper to create a new empty data-block of given type in given \a bmain database.
  *
  * \param name: can be NULL, in which case we get default name for this ID type.