For old savegames, just clear the old log dict. No need to perfectly handle case between major version.

I prefer that you use only one id and one args list for each log message. You need to use named args.

How would this work? To my knowledge, the short message and long message have different IDs, so we will need both IDs (unless we re-key relevant messages to use "%(msg_id)s_short" and "%(msg_id)s_full" for the short and long message respectively).

Yes, we can build two key with one ID by adding a prefix. However, strings.dat will disappear in the future (because it's generics and duplicate with message.po). You can help me by either use message.po or create a new _str.dat file for log message. The rational between the two is message.po contains all interface strings and _str.dat file contains all strings related to game content.

Orthewise, the idea is good.

I took a slightly different approach on this.

• We now support the old format side-by-side with the new format. In theory, we could even covert them or we can later discard then if it becomes relevant.
• We now log when techs have been researched, bases + items constructed etc. (Closes: Log more things #60)
• For existing strings, we use the original method for looking up the string (usually via strings_str.dat). For new items, we lookup the text via _ and use its way of formatting.
• The new style logs do not rely on particular strings/messages being logged. This enables us to change the message without breaking the translations and without relying on immutable keys in strings_str.dat. In fact, we can migrate from strings_str.dat style without breaking the savegame format (of new style logging).