From 1e7ee9dfa0cc5007da1cbc3331b799584af8b680 Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <solipsis@pitrou.net>
Date: Fri, 14 Sep 2012 17:28:10 +0200
Subject: [PATCH] Issue #15842: the SocketIO.{readable,writable,seekable}
 methods now raise ValueError when the file-like object is closed. Patch by
 Alessandro Moura.

---
 Lib/socket.py           | 15 +++++++++++++--
 Lib/test/test_socket.py | 11 +++++++++++
 Misc/NEWS               |  4 ++++
 3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/Lib/socket.py b/Lib/socket.py
index a93cd11248c..ea56a67d555 100644
--- a/Lib/socket.py
+++ b/Lib/socket.py
@@ -315,12 +315,23 @@ class SocketIO(io.RawIOBase):
     def readable(self):
         """True if the SocketIO is open for reading.
         """
-        return self._reading and not self.closed
+        if self.closed:
+            raise ValueError("I/O operation on closed socket.")
+        return self._reading
 
     def writable(self):
         """True if the SocketIO is open for writing.
         """
-        return self._writing and not self.closed
+        if self.closed:
+            raise ValueError("I/O operation on closed socket.")
+        return self._writing
+
+    def seekable(self):
+        """True if the SocketIO is open for seeking.
+        """
+        if self.closed:
+            raise ValueError("I/O operation on closed socket.")
+        return super().seekable()
 
     def fileno(self):
         """Return the file descriptor of the underlying socket.
diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py
index cce0d1b6eb4..e2ed21d222b 100644
--- a/Lib/test/test_socket.py
+++ b/Lib/test/test_socket.py
@@ -839,6 +839,17 @@ class GeneralModuleTests(unittest.TestCase):
             fp.close()
             self.assertEqual(repr(fp), "<_io.BufferedReader name=-1>")
 
+    def test_unusable_closed_socketio(self):
+        with socket.socket() as sock:
+            fp = sock.makefile("rb", buffering=0)
+            self.assertTrue(fp.readable())
+            self.assertFalse(fp.writable())
+            self.assertFalse(fp.seekable())
+            fp.close()
+            self.assertRaises(ValueError, fp.readable)
+            self.assertRaises(ValueError, fp.writable)
+            self.assertRaises(ValueError, fp.seekable)
+
     def testListenBacklog0(self):
         srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         srv.bind((HOST, 0))
diff --git a/Misc/NEWS b/Misc/NEWS
index 24c6b7121d5..29e2c195656 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -120,6 +120,10 @@ Core and Builtins
 Library
 -------
 
+- Issue #15842: the SocketIO.{readable,writable,seekable} methods now
+  raise ValueError when the file-like object is closed.  Patch by Alessandro
+  Moura.
+
 - Issue #15881: Fixed atexit hook in multiprocessing.  Original patch
   by Chris McDonough.