correctly handle invalid operations on streams (like writing on a non-writable one)
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index 98dc711..08e0f13 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -290,6 +290,19 @@
self.assertEqual(f.seek(-1, 2), self.LARGE)
self.assertEqual(f.read(2), b"x")
+ def test_invalid_operations(self):
+ # Try writing on a file opened in read mode and vice-versa.
+ for mode in ("w", "wb"):
+ with open(support.TESTFN, mode) as fp:
+ self.assertRaises(IOError, fp.read)
+ self.assertRaises(IOError, fp.readline)
+ with open(support.TESTFN, "rb") as fp:
+ self.assertRaises(IOError, fp.write, b"blah")
+ self.assertRaises(IOError, fp.writelines, [b"blah\n"])
+ with open(support.TESTFN, "r") as fp:
+ self.assertRaises(IOError, fp.write, "blah")
+ self.assertRaises(IOError, fp.writelines, ["blah\n"])
+
def test_raw_file_io(self):
with self.open(support.TESTFN, "wb", buffering=0) as f:
self.assertEqual(f.readable(), False)
diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
index 8d2a686..b78256e 100644
--- a/Modules/_io/textio.c
+++ b/Modules/_io/textio.c
@@ -1228,6 +1228,11 @@
CHECK_CLOSED(self);
+ if (self->encoder == NULL) {
+ PyErr_SetString(PyExc_IOError, "not writable");
+ return NULL;
+ }
+
Py_INCREF(text);
textlen = PyUnicode_GetSize(text);
@@ -1363,7 +1368,7 @@
*/
if (self->decoder == NULL) {
- PyErr_SetString(PyExc_ValueError, "no decoder");
+ PyErr_SetString(PyExc_IOError, "not readable");
return -1;
}