Change Details

Usually Curve operators calls `ED_curve_editnurb_load` and `ED_curve_editnurb_make` which creates another `cu->nurb` and free the old one. But the old `cu->nurb` may be being referenced by a `PyObject` (type `pyrna_prop_collection_Type` with pointer inited in `rna_Curve_splines_begin`). This can lead to crash or other nasty problems since `RNA_POINTER_INVALIDATE(nu_ptr)` is not called. The idea of this patch is not to free the pointers `cu->nurb` and `editnurb->nurbs`. Ref T74888 (reviewers chosen from the list in https://wiki.blender.org/wiki/Modules)

Usually Curve operators calls `ED_curve_editnurb_load` and `ED_curve_editnurb_make` which creates another `cu->nurb` and free the old one. But the old `cu->nurb` may be being referenced by a `PyObject` (type `pyrna_prop_collection_Type` with pointer inited in `rna_Curve_splines_begin`). This can lead to crash or other nasty problems since `RNA_POINTER_INVALIDATE(nu_ptr)` is not called. The idea of this patch is not to free the `cu->nurb` and `editnurb->nurbs` pointers. **How this patch solves the problem:** Although not used, the `BKE_nurbList_duplicate` logic is duplicated in `ED_curve_editnurb_load` and `ED_curve_editnurb_make` (with minor differences). Basically these functions copy the ListBase of nurbs. But to copy, the old nurb is always freed and a new one is allocated. This patch changes the behavior of `BKE_nurbList_duplicate` to reuse pointers, and deduplicates the code in` ED_curve_editnurb_load` and `ED_curve_editnurb_make` by using that BKE function. Ref T74888

Usually Curve operators calls `ED_curve_editnurb_load` and `ED_curve_editnurb_make` which creates another `cu->nurb` and free the old one. But the old `cu->nurb` may be being referenced by a `PyObject` (type `pyrna_prop_collection_Type` with pointer inited in `rna_Curve_splines_begin`). This can lead to crash or other nasty problems since `RNA_POINTER_INVALIDATE(nu_ptr)` is not called. The idea of this patch is not to free the pointers `cu->nurb` and `editnurb->nurbs` pointers. Ref T74888**How this patch solves the problem:** Although not used, the `BKE_nurbList_duplicate` logic is duplicated in `ED_curve_editnurb_load` and `ED_curve_editnurb_make` (with minor differences). Basically these functions copy the ListBase of nurbs. But to copy, the old nurb is always freed and a new one is allocated. This patch changes the behavior of `BKE_nurbList_duplicate` to reuse pointers, and deduplicates the code in` ED_curve_editnurb_load` and `ED_curve_editnurb_make` by using that BKE function. (reviewers chosen from the list in https://wiki.blender.org/wiki/Modules)Ref T74888