Sculpt-dev: commit a few temporary bugfixes

prior to merge.

If fixes are still valid after merge they will
submitted for master.

source/blender/editors/transform/transform_snap_object.cc

@@ -829,6 +829,12 @@ static bool raycastEditMesh(SnapObjectContext *sctx,
                             ListBase *r_hit_list)
 {
   bool retval = false;
+
+  if (!em) {
+    printf("%s: em was NULL!\n", __func__);
+    return false;
+  }
+
   if (em->bm->totface == 0) {
     return retval;
   }

source/blender/editors/uvedit/uvedit_select.c

@@ -653,6 +653,11 @@ void uvedit_uv_select_shared_vert(const Scene *scene,
   e_first = e_iter = l->e;
   do {
     BMLoop *l_radial_iter = e_iter->l;
+
+    if (!l_radial_iter) {
+      continue;
+    }
+
     do {
       if (l_radial_iter->v == l->v) {
         if (uvedit_face_visible_test(scene, l_radial_iter->f)) {

source/blender/windowmanager/intern/wm_event_system.c

@@ -1301,7 +1301,7 @@ static wmOperator *wm_operator_create(wmWindowManager *wm,
  * This isn't very nice but needed to redraw gizmos which are hidden while tweaking,
  * See #WM_GIZMOGROUPTYPE_DELAY_REFRESH_FOR_TWEAK for details.
  */
-static void wm_region_tag_draw_on_gizmo_delay_refresh_for_tweak(wmWindow *win, bScreen *screen)
+ATTR_NO_OPT static void wm_region_tag_draw_on_gizmo_delay_refresh_for_tweak(wmWindow *win, bScreen *screen)
 {
   ED_screen_areas_iter (win, screen, area) {
     LISTBASE_FOREACH (ARegion *, region, &area->regionbase) {
@@ -3889,7 +3889,8 @@ void wm_event_do_handlers(bContext *C)
       }
 
       if (event_queue_check_drag_prev && (win->event_queue_check_drag == false)) {
-        wm_region_tag_draw_on_gizmo_delay_refresh_for_tweak(win, screen);
+        /* Use WM_window_get_active_screen since handler may have changed screen. */
+        wm_region_tag_draw_on_gizmo_delay_refresh_for_tweak(win, WM_window_get_active_screen(win));
       }
 
       /* Update previous mouse position for following events to use. */