From 6ee2d10005a9e3f47ba6eed53d4e56b9e76f9842 Mon Sep 17 00:00:00 2001
From: Brecht Van Lommel <brechtvanlommel@gmail.com>
Date: Tue, 17 Sep 2019 13:08:37 +0200
Subject: [PATCH] Fix T69974: crashes in .blend files where 3D viewport was
 split

This was caused by a missing copy of the recently adding 3D viewport shading
ID properties.
---
 source/blender/blenkernel/intern/scene.c      |  4 +++
 .../blenloader/intern/versioning_280.c        | 25 ++++++++++++++++++-
 .../editors/space_view3d/space_view3d.c       |  4 +++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/source/blender/blenkernel/intern/scene.c b/source/blender/blenkernel/intern/scene.c
index 71668f77efe..faf3d12fdad 100644
--- a/source/blender/blenkernel/intern/scene.c
+++ b/source/blender/blenkernel/intern/scene.c
@@ -318,6 +318,10 @@ void BKE_scene_copy_data(Main *bmain, Scene *sce_dst, const Scene *sce_src, cons
                                                             flag_subdata);
   }
 
+  if (sce_src->display.shading.prop) {
+    sce_dst->display.shading.prop = IDP_CopyProperty(sce_src->display.shading.prop);
+  }
+
   BKE_sound_reset_scene_runtime(sce_dst);
 
   /* Copy sequencer, this is local data! */
diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index 62428690206..074809d10c4 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -3856,7 +3856,6 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
 
   {
     /* Versioning code until next subversion bump goes here. */
-
     if (!DNA_struct_elem_find(
             fd->filesdna, "LayerCollection", "short", "local_collections_bits")) {
       LISTBASE_FOREACH (Scene *, scene, &bmain->scenes) {
@@ -3867,5 +3866,29 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
         }
       }
     }
+
+    /* Fix wrong 3D viewport copying causing corrupt pointers (T69974). */
+    for (bScreen *screen = bmain->screens.first; screen; screen = screen->id.next) {
+      for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
+        for (SpaceLink *sl = sa->spacedata.first; sl; sl = sl->next) {
+          if (sl->spacetype == SPACE_VIEW3D) {
+            View3D *v3d = (View3D *)sl;
+
+            for (ScrArea *sa_other = screen->areabase.first; sa_other; sa_other = sa_other->next) {
+              for (SpaceLink *sl_other = sa_other->spacedata.first; sl_other;
+                   sl_other = sl_other->next) {
+                if (sl != sl_other && sl_other->spacetype == SPACE_VIEW3D) {
+                  View3D *v3d_other = (View3D *)sl_other;
+
+                  if (v3d->shading.prop == v3d_other->shading.prop) {
+                    v3d_other->shading.prop = NULL;
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
   }
 }
diff --git a/source/blender/editors/space_view3d/space_view3d.c b/source/blender/editors/space_view3d/space_view3d.c
index cfd0bf9a012..f398a122e61 100644
--- a/source/blender/editors/space_view3d/space_view3d.c
+++ b/source/blender/editors/space_view3d/space_view3d.c
@@ -345,6 +345,10 @@ static SpaceLink *view3d_duplicate(SpaceLink *sl)
     v3dn->shading.type = OB_SOLID;
   }
 
+  if (v3dn->shading.prop) {
+    v3dn->shading.prop = IDP_CopyProperty(v3do->shading.prop);
+  }
+
   /* copy or clear inside new stuff */
 
   v3dn->runtime.properties_storage = NULL;