current_translation always default to en / english Locale

[ebursztein]

Unless the use monkey patch the current_translation will always be english:
in utils.py the way the current locale is detect is this line:

locale = i18n.get_locale()

If you lookup what this does in sqlalchemy_utils/i18n.py you
find this function simply returns the babel.Locale in English

    try:
        return babel.Locale('en')

So the documentation should at least make it clear you need to monkey patch this behavior and I would also remove the dependency on this function and make it simpler how to pass your own locale detection given that there is no universal solution.

For those searching for a solution, here is how you can get it to work for Flask + Flask-Babel

def get_locale():
    if not g.get('lang', None):
        g.lang = "en"
    return g.lang

from sqlalchemy_utils import i18n
i18n.get_locale = get_locale
BABEL = Babel(app, locale_selector=get_locale)