Usernames with non-standard ASCII characters lead to an encoding error

[Edward Nash]

Having a username with a non-standard ASCII character (ä [a-umlaut] in this case) leads to the traceback below. Changing browser encoding does not solve the problem, but viewing the same page with a user with the same permissions but only normal ASCII characters in the username works fine.

Trac: 0.11.1 
Python: 2.5.2 (r252:60911, Jul 31 2008, 17:49:46) [GCC 4.2.3 (Ubuntu 4.2.3-2ubuntu7)] 
setuptools: 0.6c8 
psycopg2: 2.0.6 
Genshi: 0.5.1 
mod_python: 3.3.1 
Subversion: 1.4.6 (r28521) 
jQuery: 1.2.6 

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/Trac-0.11.1-py2.5.egg/trac/web/api.py", line 339, in send_error
    'text/html')
  File "/usr/lib/python2.5/site-packages/Trac-0.11.1-py2.5.egg/trac/web/chrome.py", line 702, in render_template
    if not req.session or not int(req.session.get('accesskeys', 0)):
  File "/usr/lib/python2.5/site-packages/Trac-0.11.1-py2.5.egg/trac/web/api.py", line 169, in __getattr__
    value = self.callbacks[name](self)
  File "/usr/lib/python2.5/site-packages/Trac-0.11.1-py2.5.egg/trac/web/main.py", line 257, in _get_session
    return Session(self.env, req)
  File "/usr/lib/python2.5/site-packages/Trac-0.11.1-py2.5.egg/trac/web/session.py", line 150, in __init__
    self.get_session(req.authname, authenticated=True)
  File "/usr/lib/python2.5/site-packages/Trac-0.11.1-py2.5.egg/trac/web/session.py", line 164, in get_session
    super(Session, self).get_session(sid, authenticated)
  File "/usr/lib/python2.5/site-packages/Trac-0.11.1-py2.5.egg/trac/web/session.py", line 56, in get_session
    (sid, int(authenticated)))
  File "/usr/lib/python2.5/site-packages/Trac-0.11.1-py2.5.egg/trac/db/util.py", line 50, in execute
    return self.cursor.execute(sql_escape_percent(sql), args)
  File "/usr/lib/python2.5/site-packages/Trac-0.11.1-py2.5.egg/trac/db/util.py", line 50, in execute
    return self.cursor.execute(sql_escape_percent(sql), args)
ProgrammingError: invalid byte sequence for encoding "UTF8": 0xe42020
HINT:  This error can also happen if the byte sequence does not match the encoding expected by the server, which is controlled by "client_encoding".

[osimons]

Duplicate of #6813.