1 files changed, 26 insertions, 9 deletions
diff --git a/Lib/rlcompleter.py b/Lib/rlcompleter.py
index 3f970536dd..378f5aa647 100644
--- a/Lib/rlcompleter.py
+++ b/Lib/rlcompleter.py
@@ -29,6 +29,7 @@ Notes:
 
 """
 
+import atexit
 import builtins
 import __main__
 
@@ -72,6 +73,12 @@ class Completer:
         if self.use_main_ns:
             self.namespace = __main__.__dict__
 
+        if not text.strip():
+            if state == 0:
+                return '\t'
+            else:
+                return None
+
         if state == 0:
             if "." in text:
                 self.matches = self.attr_matches(text)
@@ -96,13 +103,16 @@ class Completer:
         """
         import keyword
         matches = []
+        seen = {"__builtins__"}
         n = len(text)
         for word in keyword.kwlist:
             if word[:n] == text:
+                seen.add(word)
                 matches.append(word)
-        for nspace in [builtins.__dict__, self.namespace]:
+        for nspace in [self.namespace, builtins.__dict__]:
             for word, val in nspace.items():
-                if word[:n] == text and word != "__builtins__":
+                if word[:n] == text and word not in seen:
+                    seen.add(word)
                     matches.append(self._callable_postfix(val, word))
         return matches
 
@@ -129,20 +139,23 @@ class Completer:
             return []
 
         # get the content of the object, except __builtins__
-        words = dir(thisobject)
-        if "__builtins__" in words:
-            words.remove("__builtins__")
+        words = set(dir(thisobject))
+        words.discard("__builtins__")
 
         if hasattr(thisobject, '__class__'):
-            words.append('__class__')
-            words.extend(get_class_members(thisobject.__class__))
+            words.add('__class__')
+            words.update(get_class_members(thisobject.__class__))
         matches = []
         n = len(attr)
         for word in words:
-            if word[:n] == attr and hasattr(thisobject, word):
-                val = getattr(thisobject, word)
+            if word[:n] == attr:
+                try:
+                    val = getattr(thisobject, word)
+                except Exception:
+                    continue  # Exclude properties that are not set
                 word = self._callable_postfix(val, "%s.%s" % (expr, word))
                 matches.append(word)
+        matches.sort()
         return matches
 
 def get_class_members(klass):
@@ -158,3 +171,7 @@ except ImportError:
     pass
 else:
     readline.set_completer(Completer().complete)
+    # Release references early at shutdown (the readline module's
+    # contents are quasi-immortal, and the completer function holds a
+    # reference to globals).
+    atexit.register(lambda: readline.set_completer(None))