Add a note about the conflict winpdb causes with PyTables.

IPython/Extensions/ipy_winpdb.py

@@ -1,73 +1,83 b''
 """ Debug a script (like %run -d) in IPython process, Using WinPdb
 
 Usage:
 
 %wdb test.py
     run test.py, with a winpdb breakpoint at start of the file 
     
 %wdb pass
     Change the password (e.g. if you have forgotten the old one)
+
+
+Notes
+-----
+
+**WARNING**: As of March 2009 (IPython 0.10), WinPdb has a known bug, which
+causes PyTables to become impossible to import if winpdb is loaded.  Therefore,
+if you need PyTables, do *not* use this extension.
+
+For more details: https://bugs.launchpad.net/ipython/+bug/249036
 """
 
 import os
 
 import IPython.ipapi
 import rpdb2
 
 ip = IPython.ipapi.get()
 
 rpdb_started = False
 
 def wdb_f(self, arg):
     """ Debug a script (like %run -d) in IPython process, Using WinPdb
     
     Usage:
     
     %wdb test.py
         run test.py, with a winpdb breakpoint at start of the file 
         
     %wdb pass
         Change the password (e.g. if you have forgotten the old one)
         
     Note that after the script has been run, you need to do "Go" (f5) 
     in WinPdb to resume normal IPython operation.
     """
 
     global rpdb_started
     if not arg.strip():
         print __doc__
         return
         
     if arg.strip() == 'pass':
         passwd = raw_input('Enter new winpdb session password: ')
         ip.db['winpdb_pass'] = passwd
         print "Winpdb password changed"
         if rpdb_started:
             print "You need to restart IPython to use the new password"
         return 
     
     path = os.path.abspath(arg)
     if not os.path.isfile(path):
         raise IPython.ipapi.UsageError("%%wdb: file %s does not exist" % path)
     if not rpdb_started:
         passwd = ip.db.get('winpdb_pass', None)
         if passwd is None:
             import textwrap
             print textwrap.dedent("""\
             Winpdb sessions need a password that you use for attaching the external
             winpdb session. IPython will remember this. You can change the password later 
             by '%wpdb pass'
             """)
             passwd = raw_input('Enter new winpdb session password: ')
             ip.db['winpdb_pass'] = passwd
             
         print "Starting rpdb2 in IPython process"
         rpdb2.start_embedded_debugger(passwd, timeout = 0)
         rpdb_started = True
         
     rpdb2.set_temp_breakpoint(path)
     print 'It is time to attach with WinPdb (launch WinPdb if needed, File -> Attach)'
     ip.magic('%run ' + arg)
     
 
 ip.expose_magic('wdb', wdb_f)