Fix T98461: Crash running screenshot from the command-line

When launching Blender with a script creating a screenshot, the Outliner
tree wasn't initialized and built properly. That is because at this
stage, all visible regions were only tagged for a non-rebuild redraw,
not a full redraw. So ensure all regions are tagged for a full redraw
immediately after file reading. Usually the full redraw would be caused
by a file-read notifier, but the Python expression/script is executed
before notifiers are handled.

Note that even before this was crashing, the Outliner would be empty in
the created screenshot.

Additionally adds an assert to the Outliner to note assumptions
explicitly, rather than crashing later.

1 files changed, 13 insertions, 0 deletions

diff --git a/source/blender/editors/util/ed_util.c b/source/blender/editors/util/ed_util.c
index e7b3bce700e..3cfe6bd61a4 100644
--- a/source/blender/editors/util/ed_util.c
+++ b/source/blender/editors/util/ed_util.c
@@ -41,6 +41,7 @@
 #include "ED_mesh.h"
 #include "ED_object.h"
 #include "ED_paint.h"
+#include "ED_screen.h"
 #include "ED_space_api.h"
 #include "ED_util.h"
 
@@ -187,6 +188,18 @@ void ED_editors_init(bContext *C)
     ED_space_image_paint_update(bmain, wm, scene);
   }
 
+  /* Enforce a full redraw for the first time areas/regions get drawn. Further region init/refresh
+   * just triggers non-rebuild redraws (#RGN_DRAW_NO_REBUILD). Usually a full redraw would be
+   * triggered by a `NC_WM | ND_FILEREAD` notifier, but if a startup script calls an operator that
+   * redraws the window, notifiers are not handled before the operator runs. See T98461. */
+  LISTBASE_FOREACH (wmWindow *, win, &wm->windows) {
+    const bScreen *screen = WM_window_get_active_screen(win);
+
+    ED_screen_areas_iter (win, screen, area) {
+      ED_area_tag_redraw(area);
+    }
+  }
+
   ED_assetlist_storage_tag_main_data_dirty();
 
   SWAP(int, reports->flag, reports_flag_prev);