ref: Make ColibriSession.relayId non-nullable (avoid use of !!).

jicofo-selector/src/main/kotlin/org/jitsi/jicofo/bridge/Bridge.kt

@@ -149,8 +149,10 @@ class Bridge @JvmOverloads internal constructor(
      * @return the relay ID advertised by the bridge, or `null` if
      * none was advertised.
      */
-    var relayId: String? = null
-        private set
+    private var relayId: String? = null
+
+    val supportsRelay
+        get() = relayId != null
 
     private val logger: Logger = LoggerImpl(Bridge::class.java.name)
 

jicofo-selector/src/main/kotlin/org/jitsi/jicofo/bridge/BridgeSelectionStrategy.kt

@@ -123,7 +123,7 @@ abstract class BridgeSelectionStrategy {
             bridge
         } else {
             val existingBridge = conferenceBridges.keys.first()
-            if (!allowMultiBridge || existingBridge.relayId == null) {
+            if (!allowMultiBridge || !existingBridge.supportsRelay) {
                 logger.info("Existing bridge does not have a relay, will not consider other bridges.")
                 return existingBridge
             }

jicofo-selector/src/main/kotlin/org/jitsi/jicofo/bridge/Cascade.kt

@@ -24,7 +24,7 @@ import kotlin.collections.HashSet
  * A representation of a cascade of bridges.
  */
 interface Cascade<N : CascadeNode<N, L>, L : CascadeLink> {
-    val sessions: MutableMap<String?, N>
+    val sessions: MutableMap<String, N>
     fun addLinkBetween(session: N, otherSession: N, meshId: String)
     fun removeLinkTo(session: N, otherSession: N)
 }
@@ -33,15 +33,15 @@ interface Cascade<N : CascadeNode<N, L>, L : CascadeLink> {
  * A representation of a single bridge in a cascade
  */
 interface CascadeNode<N : CascadeNode<N, L>, L : CascadeLink> {
-    val relayId: String?
+    val relayId: String
     val relays: MutableMap<String, L>
 }
 
 /**
  * A representation of a link between bridges in a cascade
  */
 interface CascadeLink {
-    val relayId: String?
+    val relayId: String
     val meshId: String?
 }
 
@@ -139,7 +139,7 @@ fun <C : Cascade<N, L>, N : CascadeNode<N, L>, L : CascadeLink> C.removeNode(
     if (meshes.size > 1) {
         /* The removed node was a bridge between two or more meshes - we need to repair the cascade. */
         val disconnected = node.relays.values.groupBy { it.meshId }.values.map {
-            it.flatMap { getNodesBehind(node, it.relayId!!) }.toSet()
+            it.flatMap { getNodesBehind(node, it.relayId) }.toSet()
         }.toSet()
         val newLinks = repairFn(this, disconnected)
         newLinks.forEach { (node, other, mesh) ->

jicofo-selector/src/main/kotlin/org/jitsi/jicofo/bridge/colibri/Colibri2Session.kt

@@ -69,7 +69,7 @@ class Colibri2Session(
      * change in the context of a session. We maintain the invariant that whenever a conference has multiple sessions,
      * they all have non-null relay IDs.
      */
-    override val relayId: String? = bridge.relayId
+    override val relayId: String = bridge.jid.toString()
 
     /**
      * Whether the colibri2 conference has been created. It is created with the first endpoint allocation request

jicofo-selector/src/main/kotlin/org/jitsi/jicofo/bridge/colibri/ColibriV2SessionManager.kt

@@ -83,7 +83,7 @@ class ColibriV2SessionManager(
     /**
      * The colibri2 sessions that are currently active, mapped by the [Bridge] that they use.
      */
-    override val sessions = mutableMapOf<String?, Colibri2Session>()
+    override val sessions = mutableMapOf<String, Colibri2Session>()
 
     /**
      * The set of participants that have associated colibri2 endpoints allocated, mapped by their ID. A participant is
@@ -136,9 +136,7 @@ class ColibriV2SessionManager(
         sessions.remove(session.relayId)
         participantsBySession.remove(session)
         participants.forEach { remove(it) }
-        session.relayId?.let { removedRelayId ->
-            sessions.values.forEach { otherSession -> otherSession.expireRelay(removedRelayId) }
-        }
+        sessions.values.forEach { otherSession -> otherSession.expireRelay(session.relayId) }
         return participants.toSet()
     }
 
@@ -231,7 +229,7 @@ class ColibriV2SessionManager(
      */
     private fun getOrCreateSession(bridge: Bridge, visitor: Boolean):
         Pair<Colibri2Session, Boolean> = synchronized(syncRoot) {
-        var session = sessions[bridge.relayId]
+        var session = sessions[bridge.jid.toString()]
         if (session != null) {
             return Pair(session, false)
         }
@@ -261,14 +259,12 @@ class ColibriV2SessionManager(
             getVisibleSessionParticipants(it)
         }
 
-        session.createRelay(otherSession.relayId!!, participantsBehindOtherSession, initiator = true, meshId)
-        otherSession.createRelay(session.relayId!!, participantsBehindSession, initiator = false, meshId)
+        session.createRelay(otherSession.relayId, participantsBehindOtherSession, initiator = true, meshId)
+        otherSession.createRelay(session.relayId, participantsBehindSession, initiator = false, meshId)
     }
 
     override fun removeLinkTo(session: Colibri2Session, otherSession: Colibri2Session) {
-        otherSession.relayId?.let { removedRelayId ->
-            session.expireRelay(removedRelayId)
-        }
+        session.expireRelay(otherSession.relayId)
     }
 
     @Throws(ColibriAllocationFailedException::class, BridgeSelectionFailedException::class)
@@ -308,7 +304,7 @@ class ColibriV2SessionManager(
                     // This is a bridge selection failure, because the selector should not have returned a different
                     // bridge when Octo is not enabled.
                     throw BridgeSelectionFailedException()
-                } else if (sessions.any { it.value.relayId == null } || bridge.relayId == null) {
+                } else if (sessions.any { !it.value.bridge.supportsRelay } || !bridge.supportsRelay) {
                     logger.error("Can not enable Octo: one of the selected bridges does not support Octo.")
                     // This is a bridge selection failure, because the selector should not have returned a different
                     // bridge when one of the bridges doesn't support Octo (does not have a relay ID).
@@ -344,7 +340,7 @@ class ColibriV2SessionManager(
                                     "from ${from.relayId}."
                             }
                             // We already made sure that relayId is not null when there are multiple sessions.
-                            otherSession.updateRemoteParticipant(participantInfo, from.relayId!!, create = true)
+                            otherSession.updateRemoteParticipant(participantInfo, from.relayId, create = true)
                         }
                     }
                 }
@@ -413,7 +409,7 @@ class ColibriV2SessionManager(
         // * Do nothing (if this is due to an internal error we don't want to retry indefinitely)
         // * Re-invite the participants (possibly on the same bridge) on this bridge
         // * Re-invite the participants on this bridge to a different bridge
-        if (!sessions.containsKey(session.bridge.relayId)) {
+        if (!sessions.containsKey(session.bridge.jid.toString())) {
             val reinvite = participants[participantInfo.id] == null
             logger.warn(
                 "Response for an unknown session, will ${if (reinvite) "" else "not "} reinvite the participant."
@@ -563,7 +559,7 @@ class ColibriV2SessionManager(
                 getPathsFrom(participantInfo.session) { _, otherSession, from ->
                     if (from != null) {
                         // We make sure that relayId is not null when there are multiple sessions.
-                        otherSession.updateRemoteParticipant(participantInfo, from.relayId!!, false)
+                        otherSession.updateRemoteParticipant(participantInfo, from.relayId, false)
                     }
                 }
             }
@@ -620,12 +616,13 @@ class ColibriV2SessionManager(
         logger.debug { "Received transport from $session for relay $relayId: ${transport.toXML()}" }
         synchronized(syncRoot) {
             // It's possible a new session was started for the same bridge.
-            if (!sessions.containsKey(session.bridge.relayId) || sessions[session.bridge.relayId] != session) {
+            if (!sessions.containsKey(session.bridge.jid.toString()) ||
+                sessions[session.bridge.jid.toString()] != session
+            ) {
                 logger.info("Received a response for a session that is no longer active. Ignoring.")
                 return
             }
-            // We make sure relayId is not null when there are multiple sessions.
-            sessions.values.find { it.relayId == relayId }?.setRelayTransport(transport, session.relayId!!)
+            sessions.values.find { it.relayId == relayId }?.setRelayTransport(transport, session.relayId)
                 ?: { logger.warn("Response for a relay that is no longer active. Ignoring.") }
         }
     }

jicofo-selector/src/test/kotlin/org/jitsi/jicofo/bridge/CascadeTest.kt

@@ -26,7 +26,7 @@ import io.kotest.matchers.collections.shouldContainExactlyInAnyOrder
 import io.kotest.matchers.shouldBe
 
 class TestCascade : Cascade<TestCascadeNode, TestCascadeLink> {
-    override val sessions = HashMap<String?, TestCascadeNode>()
+    override val sessions = HashMap<String, TestCascadeNode>()
 
     var linksRemoved = 0
 

jicofo-selector/src/test/kotlin/org/jitsi/jicofo/bridge/RegionBasedSelectionTest.kt

@@ -178,7 +178,7 @@ private fun mockBridge(r: Regions, s: StressLevels) = mockk<Bridge> {
     every { stress } returns s.stress
     every { isOverloaded } returns (s == High)
     every { lastReportedStressLevel } returns s.stress
-    every { relayId } returns "dummy"
+    every { supportsRelay } returns true
     every { this@mockk.toString() } returns "MockBridge[region=$region, stress=$stress]"
 }