workaround synapse bug that would make broken PLs

d2m/actions/create-room.js

@@ -95,6 +95,11 @@ async function channelToKState(channel, guild) {
 				type: "m.room_membership",
 				room_id: spaceID
 			}]
+		},
+		"m.room.power_levels/": {
+			events: {
+				"m.room.avatar": 0
+			}
 		}
 	}
 
@@ -114,6 +119,7 @@ async function createRoom(channel, guild, spaceID, kstate) {
 	if (channel.type === DiscordTypes.ChannelType.PublicThread) threadParent = channel.parent_id
 	const invite = threadParent ? [] : ["@cadence:cadence.moe"] // TODO
 
+	const roomID = await postApplyPowerLevels(kstate, async kstate => {
 		const [convertedName, convertedTopic] = convertNameAndTopic(channel, guild, null)
 		const roomID = await api.createRoom({
 			name: convertedName,
@@ -126,12 +132,43 @@ async function createRoom(channel, guild, spaceID, kstate) {
 
 		db.prepare("INSERT INTO channel_room (channel_id, room_id, name, nick, thread_parent) VALUES (?, ?, ?, NULL, ?)").run(channel.id, roomID, channel.name, threadParent)
 
-	// Put the newly created child into the space
+		return roomID
+	})
+
+	// Put the newly created child into the space, no need to await this
 	_syncSpaceMember(channel, spaceID, roomID)
 
 	return roomID
 }
 
+/**
+ * Handling power levels separately. The spec doesn't specify what happens, Dendrite differs,
+ * and Synapse does an absolutely insane *shallow merge* of what I provide on top of what it creates.
+ * We don't want the `events` key to be overridden completely.
+ * https://github.com/matrix-org/synapse/blob/develop/synapse/handlers/room.py#L1170-L1210
+ * https://github.com/matrix-org/matrix-spec/issues/492
+ * @param {any} kstate
+ * @param {(_: any) => Promise<string>} callback must return room ID
+ * @returns {Promise<string>} room ID
+ */
+async function postApplyPowerLevels(kstate, callback) {
+	const powerLevelContent = kstate["m.room.power_levels/"]
+	const kstateWithoutPowerLevels = {...kstate}
+	delete kstateWithoutPowerLevels["m.room.power_levels/"]
+
+	/** @type {string} */
+	const roomID = await callback(kstateWithoutPowerLevels)
+
+	// Now *really* apply the power level overrides on top of what Synapse *really* set
+	if (powerLevelContent) {
+		const newRoomKState = await roomToKState(roomID)
+		const newRoomPowerLevelsDiff = ks.diffKState(newRoomKState, {"m.room.power_levels/": powerLevelContent})
+		await applyKStateDiffToRoom(roomID, newRoomPowerLevelsDiff)
+	}
+
+	return roomID
+}
+
 /**
  * @param {DiscordTypes.APIGuildChannel} channel
  */
@@ -290,5 +327,6 @@ module.exports.createAllForGuild = createAllForGuild
 module.exports.channelToKState = channelToKState
 module.exports.roomToKState = roomToKState
 module.exports.applyKStateDiffToRoom = applyKStateDiffToRoom
+module.exports.postApplyPowerLevels = postApplyPowerLevels
 module.exports._convertNameAndTopic = convertNameAndTopic
 module.exports._unbridgeRoom = _unbridgeRoom

d2m/actions/create-space.js

@@ -21,10 +21,10 @@ const ks = sync.require("../../matrix/kstate")
 async function createSpace(guild, kstate) {
 	const name = kstate["m.room.name/"].name
 	const topic = kstate["m.room.topic/"]?.topic || undefined
-
 	assert(name)
 
-	const roomID = await api.createRoom({
+	const roomID = await createRoom.postApplyPowerLevels(kstate, async kstate => {
+		return api.createRoom({
 			name,
 			preset: "private_chat", // cannot join space unless invited
 			visibility: "private",
@@ -39,6 +39,7 @@ async function createSpace(guild, kstate) {
 			},
 			initial_state: ks.kstateToState(kstate)
 		})
+	})
 	db.prepare("INSERT INTO guild_space (guild_id, space_id) VALUES (?, ?)").run(guild.id, roomID)
 	return roomID
 }

db/data-for-test.sql

@@ -34,6 +34,7 @@ CREATE TABLE IF NOT EXISTS "channel_room" (
 	"name"	TEXT,
 	"nick"	TEXT,
 	"thread_parent"	TEXT,
+	"custom_avatar"	TEXT,
 	PRIMARY KEY("channel_id")
 );
 CREATE TABLE IF NOT EXISTS "event_message" (
@@ -55,11 +56,11 @@ BEGIN TRANSACTION;
 INSERT INTO guild_space (guild_id, space_id) VALUES
 ('112760669178241024', '!jjWAGMeQdNrVZSSfvz:cadence.moe');
 
-INSERT INTO channel_room (channel_id, room_id, name, nick, thread_parent) VALUES
+INSERT INTO channel_room (channel_id, room_id, name, nick, thread_parent, custom_avatar) VALUES
-('112760669178241024', '!kLRqKKUQXcibIMtOpl:cadence.moe', 'heave', 'main', NULL),
+('112760669178241024', '!kLRqKKUQXcibIMtOpl:cadence.moe', 'heave', 'main', NULL, NULL),
-('497161350934560778', '!edUxjVdzgUvXDUIQCK:cadence.moe', 'amanda-spam', NULL, NULL),
+('497161350934560778', '!edUxjVdzgUvXDUIQCK:cadence.moe', 'amanda-spam', NULL, NULL, NULL),
-('160197704226439168', '!uCtjHhfGlYbVnPVlkG:cadence.moe', 'the-stanley-parable-channel', 'bots', NULL),
+('160197704226439168', '!uCtjHhfGlYbVnPVlkG:cadence.moe', 'the-stanley-parable-channel', 'bots', NULL, NULL),
-('1100319550446252084', '!PnyBKvUBOhjuCucEfk:cadence.moe', 'worm-farm', NULL, NULL);
+('1100319550446252084', '!PnyBKvUBOhjuCucEfk:cadence.moe', 'worm-farm', NULL, NULL, NULL);
 
 INSERT INTO sim (discord_id, sim_name, localpart, mxid) VALUES
 ('0', 'bot', '_ooye_bot', '@_ooye_bot:cadence.moe'),

matrix/api.js

@@ -169,7 +169,7 @@ async function profileSetAvatarUrl(mxid, avatar_url) {
 async function setUserPower(roomID, mxid, power) {
 	assert(roomID[0] === "!")
 	assert(mxid[0] === "@")
-	// Yes it's this hard https://github.com/matrix-org/matrix-appservice-bridge/blob/2334b0bae28a285a767fe7244dad59f5a5963037/src/components/intent.ts#L352
+	// Yes there's no shortcut https://github.com/matrix-org/matrix-appservice-bridge/blob/2334b0bae28a285a767fe7244dad59f5a5963037/src/components/intent.ts#L352
 	const powerLevels = await getStateEvent(roomID, "m.room.power_levels", "")
 	const users = powerLevels.users || {}
 	if (power != null) {

matrix/kstate.js

@@ -1,6 +1,7 @@
 // @ts-check
 
-const assert = require("assert")
+const assert = require("assert").strict
+const mixin = require("mixin-deep")
 
 /** Mutates the input. */
 function kstateStripConditionals(kstate) {
@@ -43,18 +44,32 @@ function diffKState(actual, target) {
 	// go through each key that it should have
 	for (const key of Object.keys(target)) {
 		if (!key.includes("/")) throw new Error(`target kstate's key "${key}" does not contain a slash separator; if a blank state_key was intended, add a trailing slash to the kstate key.`)
-		if (key in actual) {
+
+		if (key === "m.room.power_levels/") {
+			// Special handling for power levels, we want to deep merge the actual and target into the final state.
+			if (!(key in actual)) throw new Error(`want to apply a power levels diff, but original power level data is missing\nstarted with:  ${JSON.stringify(actual)}\nwant to apply: ${JSON.stringify(target)}`)
+			const temp = mixin({}, actual[key], target[key])
+			try {
+				assert.deepEqual(actual[key], temp)
+			} catch (e) {
+				// they differ. use the newly prepared object as the diff.
+				diff[key] = temp
+			}
+
+		} else if (key in actual) {
 			// diff
 			try {
 				assert.deepEqual(actual[key], target[key])
 			} catch (e) {
-				// they differ. reassign the target
+				// they differ. use the target as the diff.
 				diff[key] = target[key]
 			}
+
 		} else {
 			// not present, needs to be added
 			diff[key] = target[key]
 		}
+
 		// keys that are missing in "actual" will not be deleted on "target" (no action)
 	}
 	return diff

matrix/kstate.test.js

@@ -92,3 +92,57 @@ test("diffKState: detects new properties", t => {
 		}
 	)
 })
+
+test("diffKState: power levels are mixed together", t => {
+	const original = {
+		"m.room.power_levels/": {
+			"ban": 50,
+			"events": {
+				"m.room.name": 100,
+				"m.room.power_levels": 100
+			},
+			"events_default": 0,
+			"invite": 50,
+			"kick": 50,
+			"notifications": {
+				"room": 20
+			},
+			"redact": 50,
+			"state_default": 50,
+			"users": {
+				"@example:localhost": 100
+			},
+			"users_default": 0
+		}
+	}
+	const result = diffKState(original, {
+		"m.room.power_levels/": {
+			"events": {
+				"m.room.avatar": 0
+			}
+		}
+	})
+	t.deepEqual(result, {
+		"m.room.power_levels/": {
+			"ban": 50,
+			"events": {
+				"m.room.name": 100,
+				"m.room.power_levels": 100,
+				"m.room.avatar": 0
+			},
+			"events_default": 0,
+			"invite": 50,
+			"kick": 50,
+			"notifications": {
+				"room": 20
+			},
+			"redact": 50,
+			"state_default": 50,
+			"users": {
+				"@example:localhost": 100
+			},
+			"users_default": 0
+		}
+	})
+	t.notDeepEqual(original, result)
+})

package-lock.json

@@ -16,7 +16,7 @@
         "js-yaml": "^4.1.0",
         "matrix-appservice": "^2.0.0",
         "matrix-js-sdk": "^24.1.0",
-        "mixin-deep": "^2.0.1",
+        "mixin-deep": "github:cloudrac3r/mixin-deep#v3.0.0",
         "node-fetch": "^2.6.7",
         "prettier-bytes": "^1.0.4",
         "snowtransfer": "^0.8.0",
@@ -2111,9 +2111,9 @@
       }
     },
     "node_modules/mixin-deep": {
-      "version": "2.0.1",
+      "version": "3.0.0",
-      "resolved": "https://registry.npmjs.org/mixin-deep/-/mixin-deep-2.0.1.tgz",
+      "resolved": "git+ssh://git@github.com/cloudrac3r/mixin-deep.git#2dd70d6b8644263f7ed2c1620506c9eb3f11d32a",
-      "integrity": "sha512-imbHQNRglyaplMmjBLL3V5R6Bfq5oM+ivds3SKgc6oRtzErEnBUUc5No11Z2pilkUvl42gJvi285xTNswcKCMA==",
+      "license": "MIT",
       "engines": {
         "node": ">=6"
       }

package.json

@@ -22,7 +22,7 @@
     "js-yaml": "^4.1.0",
     "matrix-appservice": "^2.0.0",
     "matrix-js-sdk": "^24.1.0",
-    "mixin-deep": "^2.0.1",
+    "mixin-deep": "github:cloudrac3r/mixin-deep#v3.0.0",
     "node-fetch": "^2.6.7",
     "prettier-bytes": "^1.0.4",
     "snowtransfer": "^0.8.0",

stdin.js

@@ -14,6 +14,7 @@ const mreq = sync.require("./matrix/mreq")
 const api = sync.require("./matrix/api")
 const sendEvent = sync.require("./m2d/actions/send-event")
 const eventDispatcher = sync.require("./d2m/event-dispatcher")
+const ks = sync.require("./matrix/kstate")
 const guildID = "112760669178241024"
 
 const extraContext = {}

test/data.js

@@ -27,7 +27,7 @@ module.exports = {
 			"m.room.guest_access/": {guest_access: "can_join"},
 			"m.room.history_visibility/": {history_visibility: "invited"},
 			"m.space.parent/!jjWAGMeQdNrVZSSfvz:cadence.moe": {
-				via: ["cadence.moe"], // TODO: put the proper server here
+				via: ["cadence.moe"],
 				canonical: true
 			},
 			"m.room.join_rules/": {
@@ -40,6 +40,11 @@ module.exports = {
 			"m.room.avatar/": {
 				discord_path: "/icons/112760669178241024/a_f83622e09ead74f0c5c527fe241f8f8c.png?size=1024",
 				url: "mxc://cadence.moe/zKXGZhmImMHuGQZWJEFKJbsF"
+			},
+			"m.room.power_levels/": {
+				events: {
+					"m.room.avatar": 0
+				}
 			}
 		}
 	},