From 71df742eb4e649ecdde876081a63a4507641e620 Mon Sep 17 00:00:00 2001
From: Bastien Montagne <bastien@blender.org>
Date: Fri, 1 Mar 2024 10:41:21 +0100
Subject: [PATCH] Fix #117795: Add a validation pass on embedded liboverrides.

One of the consequences of the mistake in 3fcf535d2e (fixed in previous
commit), was that the more recent `LIB_EMBEDDED_DATA_LIB_OVERRIDE` ID
flag could be wrongly set in some nodetrees from pre-2.76 blendfiles.

This commit adds a check that embedded IDs flagged with
`LIB_EMBEDDED_DATA_LIB_OVERRIDE` are actually embedded IDs of a
liboverride.

Pull Request: https://projects.blender.org/blender/blender/pulls/118921
---
 .../blender/blenloader/BLO_blend_validate.hh  |  9 ++++++
 .../blenloader/intern/blend_validate.cc       | 28 +++++++++++++++++++
 source/blender/blenloader/intern/readfile.cc  |  2 ++
 3 files changed, 39 insertions(+)

diff --git a/source/blender/blenloader/BLO_blend_validate.hh b/source/blender/blenloader/BLO_blend_validate.hh
index 6fe25a9f22d..69f8738a11d 100644
--- a/source/blender/blenloader/BLO_blend_validate.hh
+++ b/source/blender/blenloader/BLO_blend_validate.hh
@@ -22,3 +22,12 @@ bool BLO_main_validate_libraries(Main *bmain, ReportList *reports);
  * * Check (and fix if needed) that shape key's 'from' pointer is valid.
  */
 bool BLO_main_validate_shapekeys(Main *bmain, ReportList *reports);
+
+/**
+ * Check that the `LIB_EMBEDDED_DATA_LIB_OVERRIDE` flag for embedded IDs actually matches reality
+ * of embedded IDs being used by a liboverride ID.
+ *
+ * This is needed because embedded IDs did not get their flag properly cleared when runtime data
+ * was split in `ID.tag`, which can create crashing situations in some rare cases, see #117795.
+ */
+void BLO_main_validate_embedded_liboverrides(Main *bmain, ReportList *reports);
diff --git a/source/blender/blenloader/intern/blend_validate.cc b/source/blender/blenloader/intern/blend_validate.cc
index db04b65fece..248038acfe4 100644
--- a/source/blender/blenloader/intern/blend_validate.cc
+++ b/source/blender/blenloader/intern/blend_validate.cc
@@ -20,7 +20,9 @@
 
 #include "MEM_guardedalloc.h"
 
+#include "DNA_collection_types.h"
 #include "DNA_key_types.h"
+#include "DNA_node_types.h"
 #include "DNA_sdna_types.h"
 #include "DNA_windowmanager_types.h"
 
@@ -29,6 +31,7 @@
 #include "BKE_lib_remap.hh"
 #include "BKE_library.hh"
 #include "BKE_main.hh"
+#include "BKE_node.h"
 #include "BKE_report.h"
 
 #include "BLO_blend_validate.hh"
@@ -207,3 +210,28 @@ bool BLO_main_validate_shapekeys(Main *bmain, ReportList *reports)
 
   return is_valid;
 }
+
+void BLO_main_validate_embedded_liboverrides(Main *bmain, ReportList * /*reports*/)
+{
+  ID *id_iter;
+  FOREACH_MAIN_ID_BEGIN (bmain, id_iter) {
+    bNodeTree *node_tree = ntreeFromID(id_iter);
+    if (node_tree) {
+      if (node_tree->id.flag & LIB_EMBEDDED_DATA_LIB_OVERRIDE) {
+        if (!ID_IS_OVERRIDE_LIBRARY(id_iter)) {
+          node_tree->id.flag &= ~LIB_EMBEDDED_DATA_LIB_OVERRIDE;
+        }
+      }
+    }
+
+    if (GS(id_iter->name) == ID_SCE) {
+      Scene *scene = reinterpret_cast<Scene *>(id_iter);
+      if (scene->master_collection &&
+          (scene->master_collection->id.flag & LIB_EMBEDDED_DATA_LIB_OVERRIDE))
+      {
+        scene->master_collection->id.flag &= ~LIB_EMBEDDED_DATA_LIB_OVERRIDE;
+      }
+    }
+  }
+  FOREACH_MAIN_ID_END;
+}
diff --git a/source/blender/blenloader/intern/readfile.cc b/source/blender/blenloader/intern/readfile.cc
index 527038941e9..7db3ade897d 100644
--- a/source/blender/blenloader/intern/readfile.cc
+++ b/source/blender/blenloader/intern/readfile.cc
@@ -3396,6 +3396,8 @@ static void after_liblink_merged_bmain_process(Main *bmain, BlendFileReadReport
    * so simpler to just use it directly in this single call. */
   BLO_main_validate_shapekeys(bmain, reports ? reports->reports : nullptr);
 
+  BLO_main_validate_embedded_liboverrides(bmain, reports ? reports->reports : nullptr);
+
   /* We have to rebuild that runtime information *after* all data-blocks have been properly linked.
    */
   BKE_main_collections_parent_relations_rebuild(bmain);