Cleanup: Sanitise return value of `ED_object_parent_set()`

Consistently return `false` from `ED_object_parent_set()` when parenting
is not possible. Before, when parent and child were the same object, the
function would return `true` even though the parent-child relation was
not made.

Just returning `false` in the `parent == child` case would break the
parenting operator, as `false` stops its loop over all selected objects.
This tight coupling caused T82312. The loop now has its own check for
this, so that it properly continues, and the implementation of
`ED_object_parent_set()` is decoupled from its surrounding code.

No functional changes.

1 files changed, 13 insertions, 1 deletions

diff --git a/source/blender/editors/object/object_relations.c b/source/blender/editors/object/object_relations.c
index 3d65a9e5fcb..46624a76999 100644
--- a/source/blender/editors/object/object_relations.c
+++ b/source/blender/editors/object/object_relations.c
@@ -696,7 +696,7 @@ bool ED_object_parent_set(ReportList *reports,
   /* Preconditions. */
   if (ob == par) {
     /* Parenting an object to itself is impossible. */
-    return true;
+    return false;
   }
 
   if (BKE_object_parent_loop_check(par, ob)) {
@@ -981,6 +981,12 @@ struct ParentingContext {
 static bool parent_set_nonvertex_parent(bContext *C, struct ParentingContext *parenting_context)
 {
   CTX_DATA_BEGIN (C, Object *, ob, selected_editable_objects) {
+    if (ob == parenting_context->par) {
+      /* ED_object_parent_set() will fail (and thus return false), but this case shouldn't break
+       * this loop. It's expected that the active object is also selected. */
+      continue;
+    }
+
     if (!ED_object_parent_set(parenting_context->reports,
                               C,
                               parenting_context->scene,
@@ -1005,6 +1011,12 @@ static bool parent_set_vertex_parent_with_kdtree(bContext *C,
   int vert_par[3] = {0, 0, 0};
 
   CTX_DATA_BEGIN (C, Object *, ob, selected_editable_objects) {
+    if (ob == parenting_context->par) {
+      /* ED_object_parent_set() will fail (and thus return false), but this case shouldn't break
+       * this loop. It's expected that the active object is also selected. */
+      continue;
+    }
+
     parent_set_vert_find(tree, ob, vert_par, parenting_context->is_vertex_tri);
     if (!ED_object_parent_set(parenting_context->reports,
                               C,