From fe1b22af0a9d696918204adaaae125a9bf86c5cf Mon Sep 17 00:00:00 2001
From: Benjamin Peterson <benjamin@python.org>
Date: Mon, 29 Apr 2013 10:23:08 -0400
Subject: [PATCH] ignore errors when trying to fetch sys.stdin.encoding (closes
 #17863)

---
 Misc/NEWS          |  3 +++
 Python/pythonrun.c | 17 ++++++++---------
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/Misc/NEWS b/Misc/NEWS
index eced97a6deb..0a3ef49722b 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@ What's New in Python 3.3.2?
 Core and Builtins
 -----------------
 
+- Issue #17863: In the interactive console, don't loop forever if the encoding
+  can't be fetched from stdin.
+
 - Issue #17867: Raise an ImportError if __import__ is not found in __builtins__.
 
 - Issue #17857: Prevent build failures with pre-3.5.0 versions of sqlite3,
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index dd320175741..ee6071e631e 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -1237,16 +1237,15 @@ PyRun_InteractiveOneFlags(FILE *fp, const char *filename, PyCompilerFlags *flags
     _Py_IDENTIFIER(encoding);
 
     if (fp == stdin) {
-        /* Fetch encoding from sys.stdin */
+        /* Fetch encoding from sys.stdin if possible. */
         v = PySys_GetObject("stdin");
-        if (v == NULL || v == Py_None)
-            return -1;
-        oenc = _PyObject_GetAttrId(v, &PyId_encoding);
-        if (!oenc)
-            return -1;
-        enc = _PyUnicode_AsString(oenc);
-        if (enc == NULL)
-            return -1;
+        if (v && v != Py_None) {
+            oenc = _PyObject_GetAttrId(v, &PyId_encoding);
+            if (oenc)
+                enc = _PyUnicode_AsString(oenc);
+            if (!enc)
+                PyErr_Clear();
+        }
     }
     v = PySys_GetObject("ps1");
     if (v != NULL) {