Honestly it’s like dark magic to me! Here is an example of errors I printed when trying to export messages for AnimAll:

Key not found in msgs: (' matching of objects', 'tion to get the best possible match between source and destination meshes.\nWarning: Results will never be as good as manual matching of objects')
Key not found in msgs: ('*', 'best possible match between source and destination meshes.\nWarning: Results will never be as good as manual matching of objects')

These are both parts of bpy.types.OBJECT_OT_data_transfer.use_auto_transform, so completely unrelated to AnimAll. It seems really fishy that parts of the message wound up in both the context and the message, right?

I tried to follow the logic to understand how RNA is walked and all that but it’s too much for me just yet!

So it could well be an unregister error, but it’s not clear enough to me, and I wouldn’t know how to formulate the message…

Ah, maybe I’m mistaken, but this always creates a translations.py, even for single-file scripts. I thought the intention was to create it only if the module is a directory, otherwise just put the translations at the end of the script.

If that is the case, I think this is better? Let me know.

@staticmethod
def _dst(self, path, uid, kind):
    if isinstance(path, str):
        if kind == 'PO':
            if uid == self.settings.PARSER_TEMPLATE_ID:
                if not path.endswith(".pot"):
                    return os.path.join(os.path.dirname(path), "blender.pot")
            if not path.endswith(".po"):
                return os.path.join(os.path.dirname(path), uid + ".po")
        elif kind == 'PY':
            if os.path.isdir(path):
                return os.path.join(path, "translations.py")
    return path

OK... Can't spot anything wrong on first sight in animall code, so will wait for this pathc to be committed and will try to investigate further.

BTW, a bit unrelated, but unregistration of translations in that add-on should rather happen at the start of the unregister function. By principle, it's better to always unregister exactly in the inverse order of registration.

That piece of code I proposed would be under the if not path.endswith(".py"): condition, so single py files would still be handled as expected.

it just makes it safe(r) in case we ever get a non-py file, non directory path, for whatever reason.

Note that the issue does not happen every single time, but AnimAll is not the only add-on affected, I’ve tried several and they were all—with different messages, though.

Thanks for the unregister tip, I’ll fix it!

Oh, right 🤦