GH-62052: add defer_close logic to FileIO

Modules/_io/bufferedio.c

@@ -518,6 +518,8 @@ buffered_closed_get(buffered *self, void *context)
     return PyObject_GetAttr(self->raw, &_Py_ID(closed));
 }
 
+void _PyFileIO_set_defer_close(PyObject *self, bool defer_close);
+
 /*[clinic input]
 _io._Buffered.close
 [clinic start generated code]*/
@@ -563,6 +565,10 @@ _io__Buffered_close_impl(buffered *self)
         Py_DECREF(res);
     }
 
+    if (self->fast_closed_checks) {
+        _PyFileIO_set_defer_close(self->raw, false);
+    }
+
     res = PyObject_CallMethodNoArgs(self->raw, &_Py_ID(close));
 
     if (self->buffer) {
@@ -1891,6 +1897,9 @@ _io_BufferedWriter___init___impl(buffered *self, PyObject *raw,
         Py_IS_TYPE(self, state->PyBufferedWriter_Type) &&
         Py_IS_TYPE(raw, state->PyFileIO_Type)
     );
+    if (self->fast_closed_checks) {
+        _PyFileIO_set_defer_close(self->raw, true);
+    }
 
     self->ok = 1;
     return 0;

Modules/_io/fileio.c

@@ -70,6 +70,8 @@ typedef struct {
     unsigned int blksize;
     PyObject *weakreflist;
     PyObject *dict;
+    /* if true, we are wrapped by buffer, don't close until buffer is closed */
+    bool defer_close;
 } fileio;
 
 #define PyFileIO_Check(state, op) (PyObject_TypeCheck((op), state->PyFileIO_Type))
@@ -83,6 +85,13 @@ _PyFileIO_closed(PyObject *self)
     return ((fileio *)self)->fd < 0;
 }
 
+void
+_PyFileIO_set_defer_close(PyObject *self, bool defer_close)
+{
+    ((fileio *)self)->defer_close = defer_close;
+}
+
+
 /* Because this can call arbitrary code, it shouldn't be called when
    the refcount is 0 (that is, not directly from tp_dealloc unless
    the refcount has been temporarily re-incremented). */
@@ -105,6 +114,9 @@ fileio_dealloc_warn(fileio *self, PyObject *source)
 static int
 internal_close(fileio *self)
 {
+    if (self->defer_close) {
+        return 0;
+    }
     int err = 0;
     int save_errno = 0;
     if (self->fd >= 0) {
@@ -194,6 +206,7 @@ fileio_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
         self->blksize = 0;
         self->closefd = 1;
         self->weakreflist = NULL;
+        self->defer_close = false;
     }
 
     return (PyObject *) self;