gh-127274: Defer nested methods (#128012)

Methods (functions defined in class scope) are likely to be cleaned
up by the GC anyway.

Add a new code flag, `CO_METHOD`, that is set for functions defined
in a class scope. Use that when deciding to defer functions.

4 files changed, 9 insertions, 13 deletions

diff --git a/Lib/dis.py b/Lib/dis.py
index aa22404..109c986 100644
--- a/Lib/dis.py
+++ b/Lib/dis.py
@@ -162,6 +162,7 @@ COMPILER_FLAG_NAMES = {
           256: "ITERABLE_COROUTINE",
           512: "ASYNC_GENERATOR",
     0x4000000: "HAS_DOCSTRING",
+    0x8000000: "METHOD",
 }
 
 def pretty_flags(flags):
diff --git a/Lib/inspect.py b/Lib/inspect.py
index b7d8271..5b7c4df 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -57,6 +57,7 @@ __all__ = [
     "CO_VARARGS",
     "CO_VARKEYWORDS",
     "CO_HAS_DOCSTRING",
+    "CO_METHOD",
     "ClassFoundException",
     "ClosureVars",
     "EndOfBlock",
diff --git a/Lib/test/test_monitoring.py b/Lib/test/test_monitoring.py
index 087ac8d..32b3a6a 100644
--- a/Lib/test/test_monitoring.py
+++ b/Lib/test/test_monitoring.py
@@ -850,12 +850,6 @@ class ReturnRecorder:
     def __call__(self, code, offset, val):
         self.events.append(("return", code.co_name, val))
 
-# gh-127274: CALL_ALLOC_AND_ENTER_INIT will only cache __init__ methods that
-# are deferred. We only defer functions defined at the top-level.
-class ValueErrorRaiser:
-    def __init__(self):
-        raise ValueError()
-
 
 class ExceptionMonitoringTest(CheckEvents):
 
@@ -1054,6 +1048,9 @@ class ExceptionMonitoringTest(CheckEvents):
 
     @requires_specialization_ft
     def test_no_unwind_for_shim_frame(self):
+        class ValueErrorRaiser:
+            def __init__(self):
+                raise ValueError()
 
         def f():
             try:
diff --git a/Lib/test/test_opcache.py b/Lib/test/test_opcache.py
index ad0b0c4..ba111b5 100644
--- a/Lib/test/test_opcache.py
+++ b/Lib/test/test_opcache.py
@@ -493,13 +493,6 @@ class TestLoadMethodCache(unittest.TestCase):
             self.assertFalse(f())
 
 
-# gh-127274: CALL_ALLOC_AND_ENTER_INIT will only cache __init__ methods that
-# are deferred. We only defer functions defined at the top-level.
-class MyClass:
-    def __init__(self):
-        pass
-
-
 class InitTakesArg:
     def __init__(self, arg):
         self.arg = arg
@@ -536,6 +529,10 @@ class TestCallCache(TestBase):
     @disabling_optimizer
     @requires_specialization_ft
     def test_assign_init_code(self):
+        class MyClass:
+            def __init__(self):
+                pass
+
         def instantiate():
             return MyClass()