From 49d3db92a4c3d9ddfa1babf82c9b20383725a24d Mon Sep 17 00:00:00 2001
From: Martin Panter <vadmium+py@gmail.com>
Date: Sun, 6 Dec 2015 11:12:15 +0000
Subject: [PATCH] Issue #25717: Add comment explaining why errors are ignored

---
 Modules/_io/fileio.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c
index 5f88d58c45a..dbd604a1168 100644
--- a/Modules/_io/fileio.c
+++ b/Modules/_io/fileio.c
@@ -443,6 +443,9 @@ _io_FileIO___init___impl(fileio *self, PyObject *nameobj, const char *mode,
     fstat_result = _Py_fstat_noraise(self->fd, &fdfstat);
     Py_END_ALLOW_THREADS
     if (fstat_result < 0) {
+        /* Tolerate fstat() errors other than EBADF.  See Issue #25717, where
+        an anonymous file on a Virtual Box shared folder filesystem would
+        raise ENOENT. */
 #ifdef MS_WINDOWS
         if (GetLastError() == ERROR_INVALID_HANDLE) {
             PyErr_SetFromWindowsErr(0);