[3.13] gh-125038: Fix crash after genexpr.gi_frame.f_locals manipulations (GH-125178) (#125846)

(cherry picked from commit 079875e) Co-authored-by: Mikhail Efimov <efimov.mikhail@gmail.com>

Author: JelleZijlstra

Lib/test/test_dis.py

@@ -782,6 +782,7 @@ def foo(x):
  POP_TOP
  L1: RESUME 0
  LOAD_FAST 0 (.0)
+ GET_ITER
  L2: FOR_ITER 10 (to L3)
  STORE_FAST 1 (z)
  LOAD_DEREF 2 (x)

Lib/test/test_generators.py

@@ -246,6 +246,79 @@ def loop():
 #This should not raise
 loop()
 
+
+classModifyUnderlyingIterableTest(unittest.TestCase):
+iterables= [
+range(0),
+range(20),
+ [1, 2, 3],
+ (2,),
+{13, 48, 211},
+frozenset((15, 8, 6)),
+{1: 2, 3: 4},
+ ]
+
+non_iterables= [
+None,
+42,
+3.0,
+2j,
+ ]
+
+defgenexpr(self):
+return (xforxinrange(10))
+
+defgenfunc(self):
+defgen(it):
+forxinit:
+yieldx
+returngen(range(10))
+
+defprocess_tests(self, get_generator):
+forobjinself.iterables:
+g_obj=get_generator(obj)
+withself.subTest(g_obj=g_obj, obj=obj):
+self.assertListEqual(list(g_obj), list(obj))
+
+g_iter=get_generator(iter(obj))
+withself.subTest(g_iter=g_iter, obj=obj):
+self.assertListEqual(list(g_iter), list(obj))
+
+err_regex="'.*' object is not iterable"
+forobjinself.non_iterables:
+g_obj=get_generator(obj)
+withself.subTest(g_obj=g_obj):
+self.assertRaisesRegex(TypeError, err_regex, list, g_obj)
+
+deftest_modify_f_locals(self):
+defmodify_f_locals(g, local, obj):
+g.gi_frame.f_locals[local] =obj
+returng
+
+defget_generator_genexpr(obj):
+returnmodify_f_locals(self.genexpr(), '.0', obj)
+
+defget_generator_genfunc(obj):
+returnmodify_f_locals(self.genfunc(), 'it', obj)
+
+self.process_tests(get_generator_genexpr)
+self.process_tests(get_generator_genfunc)
+
+deftest_new_gen_from_gi_code(self):
+defnew_gen_from_gi_code(g, obj):
+generator_func=types.FunctionType(g.gi_code,{})
+returngenerator_func(obj)
+
+defget_generator_genexpr(obj):
+returnnew_gen_from_gi_code(self.genexpr(), obj)
+
+defget_generator_genfunc(obj):
+returnnew_gen_from_gi_code(self.genfunc(), obj)
+
+self.process_tests(get_generator_genexpr)
+self.process_tests(get_generator_genfunc)
+
+
 classExceptionTest(unittest.TestCase):
 # Tests for the issue #23353: check that the currently handled exception
 # is correctly saved/restored in PyEval_EvalFrameEx().

Misc/NEWS.d/next/Core_and_Builtins/2024-10-09-13-53-50.gh-issue-125038.ffSLCz.rst

@@ -0,0 +1,2 @@
+Fix crash when iterating over a generator expression after direct changes on ``gi_frame.f_locals``.
+Patch by Mikhail Efimov.

Python/compile.c

@@ -5404,6 +5404,7 @@ compiler_sync_comprehension_generator(struct compiler *c, location loc,
 
 if (IS_LABEL(start)){
 depth++;
+ADDOP(c, LOC(gen->iter), GET_ITER);
 USE_LABEL(c, start);
 ADDOP_JUMP(c, LOC(gen->iter), FOR_ITER, anchor);
  }