Issue #13343: Fix a SystemError when a lambda expression uses a global
variable in the default value of a keyword-only argument:
(lambda *, arg=GLOBAL_NAME: None)
diff --git a/Lib/test/test_keywordonlyarg.py b/Lib/test/test_keywordonlyarg.py
index d7f7541..3aebd68 100644
--- a/Lib/test/test_keywordonlyarg.py
+++ b/Lib/test/test_keywordonlyarg.py
@@ -162,6 +162,14 @@
self.assertEqual(Example.f(Example(), k1=1, k2=2), (1, 2))
self.assertRaises(TypeError, Example.f, k1=1, k2=2)
+ def test_issue13343(self):
+ # The Python compiler must scan all symbols of a function to
+ # determine their scope: global, local, cell...
+ # This was not done for the default values of keyword
+ # arguments in a lambda definition, and the following line
+ # used to fail with a SystemError.
+ lambda *, k1=unittest: None
+
def test_main():
run_unittest(KeywordOnlyArgTestCase)
diff --git a/Misc/NEWS b/Misc/NEWS
index 7ef1977..e8917ed 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,10 @@
Core and Builtins
-----------------
+- Issue #13343: Fix a SystemError when a lambda expression uses a global
+ variable in the default value of a keyword-only argument:
+ (lambda *, arg=GLOBAL_NAME: None)
+
- Issue #10519: Avoid unnecessary recursive function calls in
setobject.c.
diff --git a/Python/symtable.c b/Python/symtable.c
index 5eff364..1ec51f7 100644
--- a/Python/symtable.c
+++ b/Python/symtable.c
@@ -1334,6 +1334,9 @@
return 0;
if (e->v.Lambda.args->defaults)
VISIT_SEQ(st, expr, e->v.Lambda.args->defaults);
+ if (e->v.Lambda.args->kw_defaults)
+ VISIT_KWONLYDEFAULTS(st,
+ e->v.Lambda.args->kw_defaults);
if (!symtable_enter_block(st, lambda,
FunctionBlock, (void *)e, e->lineno,
e->col_offset))