Additional autopass disable threshold - newly dumpable-on-me

[Adrianows]

Currently, you may be a "safe" minority investor in a company with 2 shares as long as there are sufficient shares in the market preventing the current president from selling down to 1. If you then enable autopass, you will continue to pass even if later someone buys from the market such that you are no longer a safe investor.

Suggested enhancement

Autopass will disable if a company in which you own enough shares to become president (2 in most games, 1 in certain cases, eg CPR in 22CA) if on your last turn the president could not dump the company on to you, but on your current turn they could.

Example:

A recent game of 1830, game 160063 action 846 https://18xx.games/game/160063?action=846 PRR has 5 market shares, no train, and two investors with 2 shares each. I buy one market share, leaving only four in the market. The non-president investor then has turn in which they can react and sell down, but does not as they appear to have auto enabled and pass instead. The president then gets their turn, and sells down to absolve themselves of the train liability.

Clearly the outcome of the above game is totally changed because a player had autopass enabled and did not react even though they could have.

[benjaminxscott]

We should probably check this here https://github.com/tobymao/18xx/blob/master/lib/engine/step/buy_sell_par_shares.rb#L381

I'd probably simplify it to whether a presidency could change at all, since that would be shenanigans

When a share is bought, whether number of shares the pres could sell which would cause a presidency change >= number of empty slots in the market

[Adrianows]

My only thought about checking whether the presidency can change at all is that in many cases you will be invested "unsafely" in good companies where the president can dump on you, but you still want to autopass because it's not a risk or may even be desirable. Admittedly, trying to check for the history to infer meaning is much more complicated to implement.

(I personally try to avoid using autopass because of nuance like this that is hard to cover all game states, but that doesn't help players who do)