I pretty much agree with jjm comment. I never have ONE config file but a directory of config files, everything is separated : database, memcache, heywatch, s3, routes, ... It's way easier for the developer, the sysadmin, the deployment, ... Of course it would multiply the risk of this happening by n files.

Thats the point. Who says it has to be a config file? Think outside the box.

Here is how Flask can do configuration (a Python micro framework):

<code>

class Config(object):

    DEBUG = False

    TESTING = False

    DATABASE_URI = 'sqlite://:memory:'

class ProductionConfig(Config):

    DATABASE_URI = 'mysql://user@localhost/foo'

class DevelopmentConfig(Config):

    DEBUG = True

class TestinConfig(Config):

    TESTING = True

</code>