Possible bug with reaction shield

2 months ago (edited)

Just a strange thing I found testing the shield spell in response to another thread:

I did a bit of testing and I can confirm that the game never offers you to cast shield as a reaction when the attack actually fails. Most of the time, it doesn't offer you to cast the spell when casting it would be a waste. This is what many players expect (RAF), but...

I think I found a bug: 

  1. In scenario 1, my wizard (AC 11) is attacked by a spider and I get the shield popup. I cast the spell and indeed I avoid the hit (attack roll was 11). The next round, I get the popup again and decide to cast the spell again... this time, the attack is successful! (and should be as the roll was 20). Why was I offered to cast shield this time and not on other rounds when the spider rolled 20?
  2. In another instance, I got the same scenario the first round, but the next round, the spider misses with attack roll of 15! (when my AC should be back to 11).

I think, there are two issues here:

1. the spell doesn't work as written in the SRD. It just lasts more than it's supposed to. The SRD says that you have a +5 bonus to AC until the start of your next turn, but as far as I can tell from my session, the bonus actually lasts until the start of your turn in the next round, which is not the same, at least not always the same. In the particuliar scenario above, my wizard was behind the spider in the initiative order, which means the bonus didn't end at the start of her next turn, but at the start of her next next turn!

It's not how the spell is supposed to work, because it makes it better if you're slow (behind in the initiative order): a PC with a poor initiative keeps her shield on her turn (interesting against opportunity attacks, for instance) while a pc with high initiative doesn't. Maybe this issue is general to other effects (improper implementation of the "next turn" concept), I don't know.

2. I think I know what the other issue is, which would probably help explain what happened in scenario 1:

Let's say the spider rolled 13 for initiative and my wizard rolled 9.

The spider attacks the wizard with an 11, and I cast shield, to negate its hit. As explained above (bug), shield is still active when the spider attacks the wizard the following round. It rolls a 20, which is enough to hit my now shielded AC (16), but I guess the AI just then checks whether it's whithin 4 of my current AC, ignoring the fact that casting shield again won't add 5 more to my AC, but just gives me AC 16 a little longer (still a bug as explained above).

Maybe point 1 is not a bug, but rather a feature (just how Tactical Adventures chose to deal with turns and rounds, but it seems unlikely for a game so otherwise true to the system).

2 months ago

We'll look into it, because this seems a bit shady and we need to look at the code.

It's strange that you're proposed to cast Shield against a 20, because even without the "always hit" rule it would be too high for the spell to be efficient.

Regarding when it ends, we need to look at the rules again and check the code.

So thanks for bringing that up.

Zaz