> I'll raise a separate ticket for a simpler stopgap design for
> 2.4.x.

This is now patch #3449.

Here's a sketch of a design to allow nations to be divided into subsets. It's aimed at solving problems recently discussed with the default nation set -- (a) allowing translators to focus on a smaller "core" of nations if they wish, (b) allowing players not to be overwhelmed by the choice -- but could find other uses. It tries to avoid the problems I pointed out in patch #3432.

This design requires changes to the network protocol and noticeable work on the client UI, so cannot be targeted at 2.4.x. I'll raise a separate ticket for a simpler stopgap design for 2.4.x.

Requirements are:

• Allow definition of subsets of the nations in a ruleset, such that when a subset is selected, no nations outside that subset will ever be used -- users can't pick them, won't be picked randomly, not used for civil war.
  • This is so that translators can choose to focus on a "core" set, be sure that untranslated strings won't appear if users choose that "core" group.
• Allow users to easily choose which subset of nations to use, in pregame (not after game start).
  • For single-player, should be as simple as a drop-down in the "pick nation" dialog.
  • For multi-player, should allow server operator to pick, or optionally, players to vote.
• Allow the same individual nation definition files to be used for different subsets, and don't complain about references outside the subset (civilwar, conflicts_with)
  • ...while still complaining about references that can't be satisfied from the full set, as this is valuable to nation maintainers for spotting typos etc.
• Allow easy definition of a user-visible "full" subset containing every nation in the ruleset, with a ruleset-defined name, without every nation definition having to remember to declare membership in this set.

Proposal:

In nations.ruleset, allow definition of a nation set with [nset_XXX]. This will look rather similar to [ngroup_XXX], and share the same namespace, but nationsets will be orthogonal to nation groups. Example usage for the case in point:

As with groups, the default set for the ruleset will be the first one defined.

Defining at least one set is mandatory (in order to give it a name). However, if only one set is defined, it will be kept out of the way of the user as much as possible.

In individual nation definitions, set membership is included in the 'groups="Foo", "Bar", "Baz"' just the same as group membership.

In nations.ruleset, define a "default_groups" list of groups/sets of which every nation is a member. Example:

Nations not in any set will cause a warning on ruleset load.

Add a server option "nationset". Value can be "" to use ruleset's default, or an explicitly set string. Allow players to vote to change this setting in pregame, but require some level of agreement.

On changing this setting, any existing nation selections not compatible with the new set go back to "random", clients only display nations/groups in the subset, effective "maxplayers" may change leading to kicks, etc -- so this is not to be done lightly.
(Could resend nations from the server when this changes, or will probably rely on client to hide unavailable nations correctly, to save network traffic on changes. Former means you only pay for "core" nation traffic at client connect if that's what you're using, latter means you don't get a massive burst of network traffic from changing a dropdown in pregame.)

Send the nation sets to the client alongside nation groups. However, they are not to be displayed in the same way as nation groups. Instead, add a drop-down in the client, on the "pick nation" dialog or similar, allowing changing the nation set (if more than one is defined). Changing this triggers a "/set nationset foo" to the server, similar to the aifill dropdown.

The effect of all this mechanism:

On game start, the random nation selection will only consider nations in the selected set. (This should be stronger even than "conflicts_with" -- it should as if the other nations don't exist.)

During the game, civilwar nations will again only be considered from the subset.