Fixed #18395 -- Reset language-related global variables with setting_changed

setting_changed = Signal(providing_args=["setting", "value"])

# Most setting_changed receivers are supposed to be added below,

# except for cases where the receiver is related to a contrib app.

@receiver(setting_changed)

def update_connections_time_zone(**kwargs):

def clear_context_processors_cache(**kwargs):

    if kwargs['setting'] == 'TEMPLATE_CONTEXT_PROCESSORS':

        context._standard_context_processors = None

@receiver(setting_changed)

def language_changed(**kwargs):

    if kwargs['setting'] in ('LOCALE_PATHS', 'LANGUAGE_CODE'):

        from django.utils.translation import trans_real

        trans_real._default = None

        if kwargs['setting'] == 'LOCALE_PATHS':

            trans_real._translations = {}