[Bf-blender-cvs] [a609e9f07ff] blender-v2.83-release: Fix T89450: Crash slicing BMEditSelSeq

[Campbell Barton]

Commit: a609e9f07ff9732b85aff2bdfe169ea785aac626
Author: Campbell Barton
Date:   Thu Aug 5 16:44:01 2021 +1000
Branches: blender-v2.83-release
https://developer.blender.org/rBa609e9f07ff9732b85aff2bdfe169ea785aac626

Fix T89450: Crash slicing BMEditSelSeq

Slicing with indices greater than the length of the sequence would crash.

===================================================================

M	source/blender/python/bmesh/bmesh_py_types_select.c

===================================================================

diff --git a/source/blender/python/bmesh/bmesh_py_types_select.c b/source/blender/python/bmesh/bmesh_py_types_select.c
index c41459f1f1e..38f0c20de47 100644
--- a/source/blender/python/bmesh/bmesh_py_types_select.c
+++ b/source/blender/python/bmesh/bmesh_py_types_select.c
@@ -207,7 +207,6 @@ static PyObject *bpy_bmeditselseq_subscript_slice(BPy_BMEditSelSeq *self,
                                                   Py_ssize_t stop)
 {
   int count = 0;
-  bool ok;
 
   PyObject *list;
   BMEditSelection *ese;
@@ -216,30 +215,22 @@ static PyObject *bpy_bmeditselseq_subscript_slice(BPy_BMEditSelSeq *self,
 
   list = PyList_New(0);
 
-  ese = self->bm->selected.first;
-
-  ok = (ese != NULL);
-
-  if (UNLIKELY(ok == false)) {
-    return list;
-  }
-
-  /* first loop up-until the start */
-  for (ok = true; ok; ok = ((ese = ese->next) != NULL)) {
+  /* First loop up-until the start. */
+  for (ese = self->bm->selected.first; ese; ese = ese->next) {
     if (count == start) {
       break;
     }
     count++;
   }
 
-  /* add items until stop */
-  do {
+  /* Add items until stop. */
+  for (; ese; ese = ese->next) {
     PyList_APPEND(list, BPy_BMElem_CreatePyObject(self->bm, &ese->ele->head));
     count++;
     if (count == stop) {
       break;
     }
-  } while ((ese = ese->next));
+  }
 
   return list;
 }