Fix a crash when the return value of a subgenerator is a temporary

amauryfa · amauryfa · commit e557da804aae · 2012-01-13T21:06:12.000+01:00
object (with a refcount of 1)
diff --git a/Lib/test/test_pep380.py b/Lib/test/test_pep380.py
@@ -364,6 +364,17 @@ def pex(e):
         ])
 
 
+    def test_exception_value_crash(self):
+        # There used to be a refcount error when the return value
+        # stored in the StopIteration has a refcount of 1.
+        def g1():
+            yield from g2()
+        def g2():
+            yield "g2"
+            return [42]
+        self.assertEqual(list(g1()), ["g2"])
+
+
     def test_generator_return_value(self):
         """
         Test generator return value
diff --git a/Objects/genobject.c b/Objects/genobject.c
@@ -475,15 +475,16 @@ PyGen_FetchStopIterationValue(PyObject **pvalue) {
         Py_XDECREF(tb);
         if (ev) {
             value = ((PyStopIterationObject *)ev)->value;
+            Py_INCREF(value);
             Py_DECREF(ev);
         }
     } else if (PyErr_Occurred()) {
         return -1;
     }
     if (value == NULL) {
         value = Py_None;
+        Py_INCREF(value);
     }
-    Py_INCREF(value);
     *pvalue = value;
     return 0;
 }

Original file line number	Diff line number	Diff line change
`@@ -475,15 +475,16 @@ PyGen_FetchStopIterationValue(PyObject **pvalue) {`
`475`	`475`	`Py_XDECREF(tb);`
`476`	`476`	`if (ev) {`
`477`	`477`	`value = ((PyStopIterationObject *)ev)->value;`
	`478`	`+ Py_INCREF(value);`
`478`	`479`	`Py_DECREF(ev);`
`479`	`480`	`}`
`480`	`481`	`} else if (PyErr_Occurred()) {`
`481`	`482`	`return -1;`
`482`	`483`	`}`
`483`	`484`	`if (value == NULL) {`
`484`	`485`	`value = Py_None;`
	`486`	`+ Py_INCREF(value);`
`485`	`487`	`}`
`486`		`- Py_INCREF(value);`
`487`	`488`	`*pvalue = value;`
`488`	`489`	`return 0;`
`489`	`490`	`}`