merge 3.4 (#11709)

Lib/pydoc.py

@@ -1415,6 +1415,8 @@ def pager(text):
 
 def getpager():
     """Decide what method to use for paging through text."""
+    if not hasattr(sys.stdin, "isatty"):
+        return plainpager
     if not hasattr(sys.stdout, "isatty"):
         return plainpager
     if not sys.stdin.isatty() or not sys.stdout.isatty():

Lib/test/test_pydoc.py

@@ -446,6 +446,14 @@ class PydocDocTest(unittest.TestCase):
         result, doc_loc = get_pydoc_text(xml.etree)
         self.assertEqual(doc_loc, "", "MODULE DOCS incorrectly includes a link")
 
+    def test_getpager_with_stdin_none(self):
+        previous_stdin = sys.stdin
+        try:
+            sys.stdin = None
+            pydoc.getpager() # Shouldn't fail.
+        finally:
+            sys.stdin = previous_stdin
+
     def test_non_str_name(self):
         # issue14638
         # Treat illegal (non-str) name like no name

Misc/NEWS

@@ -94,6 +94,9 @@ Library
 
 - Issue #20578: Add io.BufferedIOBase.readinto1.
 
+- Issue #11709: Fix the pydoc.help function to not fail when sys.stdin is not a
+  valid file.
+
 - Issue #21515: tempfile.TemporaryFile now uses os.O_TMPFILE flag is available.
 
 - Issue #13223: Fix pydoc.writedoc so that the HTML documentation for methods