Fix panic and add test for it

saulshanabrook · saulshanabrook · commit 88e2e59d3225 · 2024-05-22T15:31:21.000-04:00
diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
@@ -1430,6 +1430,27 @@ class Foo:
         Foo.attr = 0
         self.assertFalse(ex.is_valid())
 
+    def test_type_version_doesnt_segfault(self):
+        """
+        Tests that setting a type version doesn't cause a segfault when later looking at the stack.
+        """
+
+        # Minimized from mdp.py benchmark
+
+        class A:
+            def __init__(self):
+                self.attr = {}
+
+            def method(self, arg):
+                self.attr[arg] = None
+
+        def fn(a):
+            for _ in range(100):
+                (_ for _ in [])
+                (_ for _ in [a.method(None)])
+
+        fn(A())
+
 
 if __name__ == "__main__":
     unittest.main()
diff --git a/Python/optimizer_bytecodes.c b/Python/optimizer_bytecodes.c
@@ -588,7 +588,7 @@ dummy_func(void) {
         // Can determine statically, so we interleave the new locals
         // and make the current stack the new locals.
         // This also sets up for true call inlining.
-        if (sym_is_null(self_or_null) || sym_is_not_null(self_or_null)) {
+        if (sym_is_null(self_or_null)) {
             localsplus_start = args;
             n_locals_already_filled = argcount;
         }
diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h

Original file line number	Diff line number	Diff line change
`@@ -588,7 +588,7 @@ dummy_func(void) {`
`588`	`588`	`// Can determine statically, so we interleave the new locals`
`589`	`589`	`// and make the current stack the new locals.`
`590`	`590`	`// This also sets up for true call inlining.`
`591`		`- if (sym_is_null(self_or_null) \|\| sym_is_not_null(self_or_null)) {`
	`591`	`+ if (sym_is_null(self_or_null)) {`
`592`	`592`	`localsplus_start = args;`
`593`	`593`	`n_locals_already_filled = argcount;`
`594`	`594`	`}`