[Bf-blender-cvs] [ca49643f3c2] master: Fix T70965: Undo crash with specific file

[Julian Eisel]

Commit: ca49643f3c254a0bdb75f9972880c62bf7f44c3e
Author: Julian Eisel
Date:   Wed Jan 15 17:46:50 2020 +0100
Branches: master
https://developer.blender.org/rBca49643f3c254a0bdb75f9972880c62bf7f44c3e

Fix T70965: Undo crash with specific file

Not sure how the WorkSpaceLayout.screen pointer could end up being NULL,
but apparently that happens, or at least happened with older files.

Rather than just adding NULL-checks, prefer not keeping around those
invalid layouts at all.

===================================================================

M	source/blender/blenkernel/intern/workspace.c
M	source/blender/blenloader/intern/readfile.c

===================================================================

diff --git a/source/blender/blenkernel/intern/workspace.c b/source/blender/blenkernel/intern/workspace.c
index 3e449fa6b25..f58c20a7d72 100644
--- a/source/blender/blenkernel/intern/workspace.c
+++ b/source/blender/blenkernel/intern/workspace.c
@@ -247,8 +247,12 @@ WorkSpaceLayout *BKE_workspace_layout_add(Main *bmain,
 
 void BKE_workspace_layout_remove(Main *bmain, WorkSpace *workspace, WorkSpaceLayout *layout)
 {
-  id_us_min(&layout->screen->id);
-  BKE_id_free(bmain, layout->screen);
+  /* Screen should usually be set, but we call this from file reading to get rid of invalid
+   * layouts. */
+  if (layout->screen) {
+    id_us_min(&layout->screen->id);
+    BKE_id_free(bmain, layout->screen);
+  }
   BLI_freelinkN(&workspace->layouts, layout);
 }
 
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 086f1db117d..fbe270dd060 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -3377,6 +3377,11 @@ static void lib_link_workspaces(FileData *fd, Main *bmain)
           }
         }
       }
+      else {
+        /* If we're reading a layout without screen stored, it's useless and we shouldn't keep it
+         * around. */
+        BKE_workspace_layout_remove(bmain, workspace, layout);
+      }
     }
 
     id->tag &= ~LIB_TAG_NEED_LINK;