modules: always safely set up/clear memory

[HumorBaby]

Modules will safely initialize (ensure key does not exist in memory already) in setup() and clean up (remove module-specific keys from memory) in shutdown(), where necessary.

[HumorBaby]

Thinking more about the word "safely", I am brought to the question:

Wouldn't it be safer to raise something in setup() if a key is already present (where applicable)? Presumably shutdown() should remove keys, and a fresh load should not have the keys already; thus, the only time a key already exists would be an unwanted collision...

[dgw]

It depends. Sometimes it's OK to leave stuff in bot.memory so it can persist across module reloads (since we actually run shutdown() on unload now, IIRC). Things like the short-URL cache from url.py come to mind, where we don't necessarily want to have the bot hit the API again if it sees the same URL before & after reload. Basically, I think that just blanket-adding all of these might not be the best approach.

Let's see if I can come up with pros/cons for each of these.

[HumorBaby]

hmmm, I was worried about that. I will rack my brain also to see where it makes sense to persist memory.

…

On April 24, 2019 5:58:21 PM EDT, dgw ***@***.***> wrote: It depends. Sometimes it's OK to leave stuff in `bot.memory` so it can persist across module reloads (since we actually run `shutdown()` on unload now, IIRC). Things like the short-URL cache from `url.py` come to mind, where we don't necessarily want to have the bot hit the API again if it sees the same URL before & after reload. Basically, I think that just blanket-adding all of these might not be the best approach. Let's see if I can come up with pros/cons for each of these. -- You are receiving this because you authored the thread. Reply to this email directly or view it on GitHub: #1569 (comment)

[dgw]

Here are some evaluations of whether it makes sense to clear each memory key, as promised (though it took a bit longer than expected).

[dgw]

This brought up a new issue (which I'll open shortly), but I believe everything to be done here has been.