fix: uninitialized exception for lateinit guardSnode in certain cases, replace with a nullable version for error handling (#926)

libsession/src/main/java/org/session/libsession/snode/OnionRequestAPI.kt

@@ -308,10 +308,11 @@ object OnionRequestAPI {
      */
     private fun sendOnionRequest(destination: Destination, payload: Map<*, *>): Promise<Map<*, *>, Exception> {
         val deferred = deferred<Map<*, *>, Exception>()
-        lateinit var guardSnode: Snode
+        var guardSnode: Snode? = null
         buildOnionForDestination(payload, destination).success { result ->
             guardSnode = result.guardSnode
-            val url = "${guardSnode.address}:${guardSnode.port}/onion_req/v2"
+            val nonNullGuardSnode = result.guardSnode
+            val url = "${nonNullGuardSnode.address}:${nonNullGuardSnode.port}/onion_req/v2"
             val finalEncryptionResult = result.finalEncryptionResult
             val onion = finalEncryptionResult.ciphertext
             if (destination is Destination.Server && onion.count().toDouble() > 0.75 * FileServerAPIV2.maxFileSize.toDouble()) {
@@ -398,13 +399,17 @@ object OnionRequestAPI {
         val promise = deferred.promise
         promise.fail { exception ->
             if (exception is HTTP.HTTPRequestFailedException && SnodeModule.isInitialized) {
-                val path = paths.firstOrNull { it.contains(guardSnode) }
+                val checkedGuardSnode = guardSnode
+                val path =
+                    if (checkedGuardSnode == null) null
+                    else paths.firstOrNull { it.contains(checkedGuardSnode) }
+
                 fun handleUnspecificError() {
                     if (path == null) { return }
                     var pathFailureCount = OnionRequestAPI.pathFailureCount[path] ?: 0
                     pathFailureCount += 1
                     if (pathFailureCount >= pathFailureThreshold) {
-                        dropGuardSnode(guardSnode)
+                        guardSnode?.let { dropGuardSnode(it) }
                         path.forEach { snode ->
                             @Suppress("ThrowableNotThrown")
                             SnodeAPI.handleSnodeError(exception.statusCode, exception.json, snode, null) // Intentionally don't throw