From 955056a04fabaa184a38bbf3c65733f69f855f80 2013-09-03 23:50:48
From: Thomas Kluyver <takowl@gmail.com>
Date: 2013-09-03 23:50:48
Subject: [PATCH] Merge pull request #4083 from takluyver/better-hidden-ns

Implement a better check for hidden values for %who etc.
---

diff --git a/IPython/core/interactiveshell.py b/IPython/core/interactiveshell.py
index 3453fc6..d084aa7 100644
--- a/IPython/core/interactiveshell.py
+++ b/IPython/core/interactiveshell.py
@@ -970,7 +970,7 @@ class InteractiveShell(SingletonConfigurable):
 
         # A record of hidden variables we have added to the user namespace, so
         # we can list later only variables defined in actual interactive use.
-        self.user_ns_hidden = set()
+        self.user_ns_hidden = {}
 
         # Now that FakeModule produces a real module, we've run into a nasty
         # problem: after script execution (via %run), the module where the user
@@ -1150,7 +1150,7 @@ class InteractiveShell(SingletonConfigurable):
         
         Note that this does not include the displayhook, which also caches
         objects from the output."""
-        return [self.user_ns, self.user_global_ns] + \
+        return [self.user_ns, self.user_global_ns, self.user_ns_hidden] + \
                [m.__dict__ for m in self._main_mod_cache.values()]
 
     def reset(self, new_session=True):
@@ -1301,7 +1301,8 @@ class InteractiveShell(SingletonConfigurable):
         # And configure interactive visibility
         user_ns_hidden = self.user_ns_hidden
         if interactive:
-            user_ns_hidden.difference_update(vdict)
+            for name in vdict:
+                user_ns_hidden.pop(name, None)
         else:
             user_ns_hidden.update(vdict)
     
@@ -1321,7 +1322,7 @@ class InteractiveShell(SingletonConfigurable):
         for name, obj in variables.iteritems():
             if name in self.user_ns and self.user_ns[name] is obj:
                 del self.user_ns[name]
-                self.user_ns_hidden.discard(name)
+                self.user_ns_hidden.pop(name, None)
 
     #-------------------------------------------------------------------------
     # Things related to object introspection
diff --git a/IPython/core/magics/namespace.py b/IPython/core/magics/namespace.py
index 36f2d02..a469479 100644
--- a/IPython/core/magics/namespace.py
+++ b/IPython/core/magics/namespace.py
@@ -265,9 +265,10 @@ class NamespaceMagics(Magics):
 
         user_ns = self.shell.user_ns
         user_ns_hidden = self.shell.user_ns_hidden
+        nonmatching = object()  # This can never be in user_ns
         out = [ i for i in user_ns
                 if not i.startswith('_') \
-                and not i in user_ns_hidden ]
+                and (user_ns[i] is not user_ns_hidden.get(i, nonmatching)) ]
 
         typelist = parameter_s.split()
         if typelist: