commit 927f07c816aad9f8ed961d7ace6a367837f7fa8f
author Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Mon Oct 14 04:40:15 2019 -0700
committer Łukasz Langa <lukasz@langa.pl> Mon Oct 14 13:40:15 2019 +0200
tree 6fdf864d74436422335c89ebdff2f3afbc66866f
parent ac53ba6c7c0c43100bab8bc427d54563d9b65a0e

bpo-38469: Handle named expression scope with global/nonlocal keywords (GH-16755) (#16760)

The symbol table handing of PEP572's assignment expressions is not resolving correctly the scope of some variables in presence of global/nonlocal keywords in conjunction with comprehensions.
(cherry picked from commit fd5c414880b2e05720b9cf14ab0b0d7ae2b7d925)

Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>

Python/symtable.c

diff --git a/Python/symtable.c b/Python/symtable.c
index f2453db..b871358 100644
--- a/Python/symtable.c
+++ b/Python/symtable.c
@@ -1467,10 +1467,16 @@
             continue;
         }
 
-        /* If we find a FunctionBlock entry, add as NONLOCAL/LOCAL */
+        /* If we find a FunctionBlock entry, add as GLOBAL/LOCAL or NONLOCAL/LOCAL */
         if (ste->ste_type == FunctionBlock) {
-            if (!symtable_add_def(st, target_name, DEF_NONLOCAL))
-                VISIT_QUIT(st, 0);
+            long target_in_scope = _PyST_GetSymbol(ste, target_name);
+            if (target_in_scope & DEF_GLOBAL) {
+                if (!symtable_add_def(st, target_name, DEF_GLOBAL))
+                    VISIT_QUIT(st, 0);
+            } else {
+                if (!symtable_add_def(st, target_name, DEF_NONLOCAL))
+                    VISIT_QUIT(st, 0);
+            }
             if (!symtable_record_directive(st, target_name, e->lineno, e->col_offset))
                 VISIT_QUIT(st, 0);