Hello, just wanted to share something I just experienced.
I have an appengine app running on python and for several notifications in spanish I use a messages.py file which is loaded in almost every handler. This file gave me no issues given it wasn't containing any specification for encoding. It consists in several lines practically identical to the following:
user_pass_mismatch = unicode('El usuario y contraseña no coinciden. Por favor intenta de nuevo.','utf-8')
It gave me no issues while running my app for several months, but lately I just added a set of warmup requests and it started giving 500 errors all the way because of:
SyntaxError: Non-ASCII character '\xc3' in file messages.py on line 1, but no encoding declared; see http://www.python.org/peps/pep-0263.html for details
Of course, adding the header # -*- coding: utf-8 -*- solved the issue, but the weird behavior is that non-resident (non warmup) instances caused no trouble even they didn't specified the encoding declaration.
Best,
Chuy