I'm working with Django 1.5.1 and I'm experiencing some "strange behaviour" with translations. I'm using ugettext and ugettext_lazy in the same Python file. If I organize the imports as:
from django.utils.translation import ugettext as trans
from django.utils.translation import ugettext_lazy as _
or
from django.utils.translation import ugettext as trans, ugettext_lazy as _
The strings marked as trans("string") are skipped when running makemessages command.
However, if I don't rename the ugettext it works well with both versions:
from django.utils.translation import ugettext
from django.utils.translation import ugettext_lazy as _
or
from django.utils.translation import ugettext, ugettext_lazy as _
Now trans("string") works well.
So, does anybody know why this import renaming is causing the renamed function not to be called? Is this an actual Python "limitation" I didn't know when renaming more than one function inside the same module?
UPDATE
After some testing, I've realized that even creating an empty python module inside an app with the following code it doesn't work:
from django.utils.translation import ugettext_lazy as translate
a = translate("string")
However, if using _ for the alias it works:
from django.utils.translation import ugettext_lazy as _
a = _("string")
My conclusion is: You can only use the _ alias for ugettext and ugettext_lazy (or any other related translation function) in Django or else it won't be recognized by makemessages command. The technical explanation can be found in Robert Lujo's answer.