[Freeciv-Dev] (PR#4100) Transitive treaties under alliance

["Per I. Mathisen" <per@xxxxxxxxxxx>]

On Mon, 28 Apr 2003, ChrisK@xxxxxxxx wrote:
> > > I'm starting to wonder whether this situation is in fact a bug. Should it
> > > really be possible to declare war on an ally's ally?
> >
> > No.
> >
> > > Shouldn't a
> > > declaration of war on a player automatically lead to its allies also
> > > declaring war on you?
> >
> > Yes.
...
> I think alliances have to be transitive. War state is not.
>
> So make an alliance is only allowed when all allies of A are at least
> neutral with all allies of B. When the alliance actually happens, all allies
> of A and B become allied to each other.
>
> When A cancels an alliance with B, all his other alliances are cancelled,
> too.

What if allied(A, B) and allied(C, D), and then war(A, C) and peace(A, D)
while war(B, D) and peace(B, C)? You don't get stacking problems, but it
is still pretty schizophrenic.

To sum up:

I see five different solutions:
1) Keep the present approach.
2) Make only alliances transitive.
3) Make both war and alliance transitive when in alliance.
4) Make war, ceasefire and alliance transitive when in alliance.
5) Make all treaties transitive when in alliance.

I think 3 and 4 are bad, since in 3 we can get to exactly the situation we
want to avoid with transitive war as alliance members make individual
peace deals while in 4 all treaties are transitive except peace which is
inconsistent. I'd prefer 5 myself.

I see four ways to implement this:
1) Any alliance member can negotiate treaties and declare war on behalf of
her alliance.
2) Only the most powerful member of the alliance can do so. (This is the
solution presently adopted in the AI diplomacy patch to solve alliance
deadlocks.)
3) First player to initiate an alliance becomes its leader. In diplomacy
dialog, you can give away the leadership position.
4) We implement one new diplomacy meeting possibility: "Meet with Alliance
of X". All treaties options are disabled for individual meet dialogs.
Instead, when A "meet with Alliance of B", there may be multiple players
on both sides (allies of A on one side and allies of B on the other), and
for all these the diplomacy dialog pops up. Only treaties are possible. If
any player cancel their diplomacy meet dialog, the meeting is off. All
players on both sides must 'ok' a deal if it is to be put into effect.

  - Per