Issue #13070: Fix a crash when a TextIOWrapper caught in a reference cycle
would be finalized after the reference to its underlying BufferedRWPair's
writer got cleared by the GC.
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index 608fc41..003a4f3 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -2338,6 +2338,21 @@
with self.open(support.TESTFN, "rb") as f:
self.assertEqual(f.read(), b"456def")
+ def test_rwpair_cleared_before_textio(self):
+ # Issue 13070: TextIOWrapper's finalization would crash when called
+ # after the reference to the underlying BufferedRWPair's writer got
+ # cleared by the GC.
+ for i in range(1000):
+ b1 = self.BufferedRWPair(self.MockRawIO(), self.MockRawIO())
+ t1 = self.TextIOWrapper(b1, encoding="ascii")
+ b2 = self.BufferedRWPair(self.MockRawIO(), self.MockRawIO())
+ t2 = self.TextIOWrapper(b2, encoding="ascii")
+ # circular references
+ t1.buddy = t2
+ t2.buddy = t1
+ support.gc_collect()
+
+
class PyTextIOWrapperTest(TextIOWrapperTest):
pass
diff --git a/Misc/NEWS b/Misc/NEWS
index 71a346d..d89ef68 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -217,6 +217,10 @@
Extension Modules
-----------------
+- Issue #13070: Fix a crash when a TextIOWrapper caught in a reference cycle
+ would be finalized after the reference to its underlying BufferedRWPair's
+ writer got cleared by the GC.
+
- Issue #12881: ctypes: Fix segfault with large structure field names.
- Issue #13013: ctypes: Fix a reference leak in PyCArrayType_from_ctype.
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index 73f924e..1b81647 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -2179,6 +2179,11 @@
static PyObject *
bufferedrwpair_closed_get(rwpair *self, void *context)
{
+ if (self->writer == NULL) {
+ PyErr_SetString(PyExc_RuntimeError,
+ "the BufferedRWPair object is being garbage-collected");
+ return NULL;
+ }
return PyObject_GetAttr((PyObject *) self->writer, _PyIO_str_closed);
}