State-reset and security mitigations.

Upgrade Ruma to present.

The following are intentionally benign for activation in a later commit:

- Hydra backports not default.
- Room version 12 not default.
- Room version 12 not listed as stable.

Do not enable them manually or you can brick your database.

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/info/room_version.rs

@@ -2,10 +2,19 @@
 
 use std::iter::once;
 
-use ruma::{RoomVersionId, api::client::discovery::get_capabilities::RoomVersionStability};
+use ruma::{RoomVersionId, api::client::discovery::get_capabilities::v3::RoomVersionStability};
 
 use crate::{at, is_equal_to};
 
+/// Partially supported non-compliant room versions
+pub const UNSTABLE_ROOM_VERSIONS: &[RoomVersionId] = &[
+	RoomVersionId::V1,
+	RoomVersionId::V2,
+	RoomVersionId::V3,
+	RoomVersionId::V4,
+	RoomVersionId::V5,
+];
+
 /// Supported and stable room versions
 pub const STABLE_ROOM_VERSIONS: &[RoomVersionId] = &[
 	RoomVersionId::V6,
@@ -16,9 +25,8 @@ pub const STABLE_ROOM_VERSIONS: &[RoomVersionId] = &[
 	RoomVersionId::V11,
 ];
 
-/// Experimental, partially supported room versions
-pub const UNSTABLE_ROOM_VERSIONS: &[RoomVersionId] =
-	&[RoomVersionId::V2, RoomVersionId::V3, RoomVersionId::V4, RoomVersionId::V5];
+/// Experimental and prototype room versions under development.
+pub const EXPERIMENTAL_ROOM_VERSIONS: &[RoomVersionId] = &[RoomVersionId::V12];
 
 type RoomVersion = (RoomVersionId, RoomVersionStability);
 
@@ -31,8 +39,15 @@ impl crate::Server {
 
 	#[inline]
 	pub fn supported_room_versions(&self) -> impl Iterator<Item = RoomVersionId> + '_ {
+		let experimental_room_versions = EXPERIMENTAL_ROOM_VERSIONS
+			.iter()
+			.cloned()
+			.zip(once(RoomVersionStability::Unstable).cycle())
+			.filter(|_| self.config.allow_experimental_room_versions);
+
 		Self::available_room_versions()
 			.filter(|(_, stability)| self.supported_stability(stability))
+			.chain(experimental_room_versions)
 			.map(at!(0))
 	}