Revert "Cleanup: remove redundant active object NULL check & poll"

This reverts commit 54ea3562406c633dc69f59697cca3cd1cded3bcd it
introduced crashes when trying to go to edit mode when the active
object was hidden.

Fix T76837

1 files changed, 21 insertions, 5 deletions

diff --git a/source/blender/editors/object/object_edit.c b/source/blender/editors/object/object_edit.c
index ab82f3c3f04..0922e8078aa 100644
--- a/source/blender/editors/object/object_edit.c
+++ b/source/blender/editors/object/object_edit.c
@@ -1391,20 +1391,35 @@ static const EnumPropertyItem *object_mode_set_itemsf(bContext *C,
   return item;
 }
 
+static bool object_mode_set_poll(bContext *C)
+{
+  /* Since Grease Pencil editmode is also handled here,
+   * we have a special exception for allowing this operator
+   * to still work in that case when there's no active object
+   * so that users can exit editmode this way as per normal.
+   */
+  if (ED_operator_object_active_editable(C)) {
+    return true;
+  }
+  else {
+    return (CTX_data_gpencil_data(C) != NULL);
+  }
+}
+
 static int object_mode_set_exec(bContext *C, wmOperator *op)
 {
   bool use_submode = STREQ(op->idname, "OBJECT_OT_mode_set_with_submode");
   Object *ob = CTX_data_active_object(C);
   eObjectMode mode = RNA_enum_get(op->ptr, "mode");
-  eObjectMode restore_mode = ob->mode;
+  eObjectMode restore_mode = (ob) ? ob->mode : OB_MODE_OBJECT;
   const bool toggle = RNA_boolean_get(op->ptr, "toggle");
 
   /* by default the operator assume is a mesh, but if gp object change mode */
-  if ((ob->type == OB_GPENCIL) && (mode == OB_MODE_EDIT)) {
+  if ((ob != NULL) && (ob->type == OB_GPENCIL) && (mode == OB_MODE_EDIT)) {
     mode = OB_MODE_EDIT_GPENCIL;
   }
 
-  if (!ED_object_mode_compat_test(ob, mode)) {
+  if (!ob || !ED_object_mode_compat_test(ob, mode)) {
     return OPERATOR_PASS_THROUGH;
   }
 
@@ -1441,7 +1456,7 @@ static int object_mode_set_exec(bContext *C, wmOperator *op)
   }
 
   /* if type is OB_GPENCIL, set cursor mode */
-  if (ob->type == OB_GPENCIL) {
+  if ((ob) && (ob->type == OB_GPENCIL)) {
     if (ob->data) {
       bGPdata *gpd = (bGPdata *)ob->data;
       ED_gpencil_setup_modes(C, gpd, ob->mode);
@@ -1476,7 +1491,8 @@ void OBJECT_OT_mode_set(wmOperatorType *ot)
 
   /* api callbacks */
   ot->exec = object_mode_set_exec;
-  ot->poll = ED_operator_object_active_editable;
+
+  ot->poll = object_mode_set_poll;  // ED_operator_object_active_editable;
 
   /* flags */
   ot->flag = 0; /* no register/undo here, leave it to operators being called */