[generator] Raise StopIteration(value) with value from the return stmt (#157152)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/157152
Approved by: https://github.com/zou3519
ghstack dependencies: #157148

test/dynamo/cpython/3_13/test_generators.diff

@@ -1,5 +1,5 @@
 diff --git a/test/dynamo/cpython/3_13/test_generators.py b/test/dynamo/cpython/3_13/test_generators.py
-index e48d79d34f4..a48da0914b9 100644
+index 515fe7407f1..a48da0914b9 100644
 --- a/test/dynamo/cpython/3_13/test_generators.py
 +++ b/test/dynamo/cpython/3_13/test_generators.py
 @@ -1,3 +1,56 @@
@@ -105,7 +105,8 @@ index e48d79d34f4..a48da0914b9 100644
 +                return self.val
 +
 +            # No __iter__ method
-+
+ 
+-class ModifyUnderlyingIterableTest(unittest.TestCase):
 +        class C:
 +
 +            def __iter__(self):
@@ -113,8 +114,7 @@ index e48d79d34f4..a48da0914b9 100644
 +
 +        self.assertEqual([1,2], list(i for i in C()))
 +
- 
++
--class ModifyUnderlyingIterableTest(unittest.TestCase):
 +class ModifyUnderlyingIterableTest(__TestCase):
      iterables = [
          range(0),
@@ -137,99 +137,16 @@ index e48d79d34f4..a48da0914b9 100644
  
      def test_close_no_return_value(self):
          def f():
-@@ -630,90 +706,7 @@ class GeneratorCloseTest(unittest.TestCase):
+@@ -630,7 +706,7 @@ class GeneratorCloseTest(unittest.TestCase):
          self.assertIsNone(f_wr())
  
  
--# See https://github.com/python/cpython/issues/125723
--class GeneratorDeallocTest(unittest.TestCase):
--    def test_frame_outlives_generator(self):
--        def g1():
--            a = 42
--            yield sys._getframe()
--
--        def g2():
--            a = 42
--            yield
--
--        def g3(obj):
--            a = 42
--            obj.frame = sys._getframe()
--            yield
--
--        class ObjectWithFrame():
--            def __init__(self):
--                self.frame = None
--
--        def get_frame(index):
--            if index == 1:
--                return next(g1())
--            elif index == 2:
--                gen = g2()
--                next(gen)
--                return gen.gi_frame
--            elif index == 3:
--                obj = ObjectWithFrame()
--                next(g3(obj))
--                return obj.frame
--            else:
--                return None
--
--        for index in (1, 2, 3):
--            with self.subTest(index=index):
--                frame = get_frame(index)
--                frame_locals = frame.f_locals
--                self.assertIn('a', frame_locals)
--                self.assertEqual(frame_locals['a'], 42)
--
--    def test_frame_locals_outlive_generator(self):
--        frame_locals1 = None
--
--        def g1():
--            nonlocal frame_locals1
--            frame_locals1 = sys._getframe().f_locals
--            a = 42
--            yield
--
--        def g2():
--            a = 42
--            yield sys._getframe().f_locals
--
--        def get_frame_locals(index):
--            if index == 1:
--                nonlocal frame_locals1
--                next(g1())
--                return frame_locals1
--            if index == 2:
--                return next(g2())
--            else:
--                return None
--
--        for index in (1, 2):
--            with self.subTest(index=index):
--                frame_locals = get_frame_locals(index)
--                self.assertIn('a', frame_locals)
--                self.assertEqual(frame_locals['a'], 42)
--
--    def test_frame_locals_outlive_generator_with_exec(self):
--        def g():
--            a = 42
--            yield locals(), sys._getframe().f_locals
--
--        locals_ = {'g': g}
--        for i in range(10):
--            exec("snapshot, live_locals = next(g())", locals=locals_)
--            for l in (locals_['snapshot'], locals_['live_locals']):
--                self.assertIn('a', l)
--                self.assertEqual(l['a'], 42)
--
--
 -class GeneratorThrowTest(unittest.TestCase):
 +class GeneratorThrowTest(__TestCase):
  
      def test_exception_context_with_yield(self):
          def f():
-@@ -812,7 +805,7 @@ class GeneratorThrowTest(unittest.TestCase):
+@@ -729,7 +805,7 @@ class GeneratorThrowTest(unittest.TestCase):
              gen.throw(ValueError)
  
  
@@ -238,7 +155,7 @@ index e48d79d34f4..a48da0914b9 100644
  
      def check_stack_names(self, frame, expected):
          names = []
-@@ -861,7 +854,7 @@ class GeneratorStackTraceTest(unittest.TestCase):
+@@ -778,7 +854,7 @@ class GeneratorStackTraceTest(unittest.TestCase):
          self.check_yield_from_example(call_throw)
  
  
@@ -247,7 +164,7 @@ index e48d79d34f4..a48da0914b9 100644
      def test_generator_gi_yieldfrom(self):
          def a():
              self.assertEqual(inspect.getgeneratorstate(gen_b), inspect.GEN_RUNNING)
-@@ -2752,21 +2745,27 @@ test_generators just happened to be the test that drew these out.
+@@ -2669,21 +2745,27 @@ test_generators just happened to be the test that drew these out.
  
  """
  

test/dynamo/test_generator.py

@@ -1515,6 +1515,76 @@ class TestGeneratorThrow(GeneratorTestsBase):
 
         self._compile_check(fn)
 
+    def test_return_const_value_in_except_and_finally(self):
+        def whoo():
+            try:
+                yield 1
+            except ValueError:
+                return 2  # noqa: B901
+            finally:
+                return 3  # noqa: B012, SIM107, B901
+
+        def fn(t):
+            gen = whoo()
+            next(gen)
+            try:
+                gen.throw(ValueError)
+            except StopIteration as e:
+                assert e.args[0] == 3
+            except Exception as e:
+                raise AssertionError from e
+            return t.sin()
+
+        self._compile_check(fn)
+
+    def test_return_value_in_except_and_finally(self):
+        class Foo:
+            def __init__(self, x):
+                self.x = x
+
+        def whoo():
+            try:
+                yield 1
+            except ValueError:
+                return Foo(2)  # noqa: B901
+            finally:
+                return Foo(3)  # noqa: B012, SIM107, B901
+
+        def fn(t):
+            gen = whoo()
+            next(gen)
+            try:
+                gen.throw(ValueError)
+            except StopIteration as e:
+                assert e.args[0].x == 3
+            except Exception as e:
+                raise AssertionError from e
+            return t.sin()
+
+        self._compile_check(fn)
+
+    def test_return_None_in_except_and_finally(self):
+        def whoo():
+            try:
+                yield 1
+            except ValueError:
+                return 2  # noqa: B901
+            finally:
+                return  # noqa: B012, SIM107
+
+        def fn(t):
+            gen = whoo()
+            next(gen)
+            try:
+                gen.throw(ValueError)
+            except StopIteration as e:
+                assert len(e.args) == 0
+            except Exception as e:
+                raise AssertionError from e
+            return t.sin()
+
+        self._compile_check(fn)
+
 
 instantiate_parametrized_tests(GeneratorTests)
 instantiate_parametrized_tests(TestGeneratorSend)

torch/_dynamo/symbolic_convert.py

@@ -3982,7 +3982,13 @@ class InliningInstructionTranslator(InstructionTranslatorBase):
             ):
                 assert isinstance(self, InliningGeneratorInstructionTranslator)
                 # When the generator returns None, we raise StopIteration
-                exc.raise_observed_exception(StopIteration, self)
+                args = []
+                if not (
+                    isinstance(self.symbolic_result, ConstantVariable)
+                    and self.symbolic_result.value is None
+                ):
+                    args = [self.symbolic_result]
+                exc.raise_observed_exception(StopIteration, self, args=args)
             else:
                 return self.symbolic_result
         else: