Issue #10253: FileIO leaks a file descriptor when trying to open a file

for append that isn't seekable.  Patch by Brian Brazil.

Lib/test/test_fileio.py

@@ -339,6 +339,7 @@ class OtherFileTests(unittest.TestCase):
         f.truncate(15)
         self.assertEqual(f.tell(), 5)
         self.assertEqual(f.seek(0, os.SEEK_END), 15)
+        f.close()
 
     def testTruncateOnWindows(self):
         def bug801631():

Misc/NEWS

@@ -57,6 +57,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #10253: FileIO leaks a file descriptor when trying to open a file
+  for append that isn't seekable.  Patch by Brian Brazil.
+
 - Support context manager protocol for file-like objects returned by
   mailbox ``get_file()`` methods.
 

Modules/_io/fileio.c

@@ -396,8 +396,13 @@ fileio_init(PyObject *oself, PyObject *args, PyObject *kwds)
            end of file (otherwise, it might be done only on the
            first write()). */
         PyObject *pos = portable_lseek(self->fd, NULL, 2);
-        if (pos == NULL)
+        if (pos == NULL) {
+            if (closefd) {
+                close(self->fd);
+                self->fd = -1;
+            }
             goto error;
+        }
         Py_DECREF(pos);
     }