Fix missed error handling case

SignalServiceKit/src/Loki/API/Onion Requests/OnionRequestAPI.swift

@@ -339,7 +339,13 @@ public enum OnionRequestAPI {
             }
         }
         promise.catch2 { error in // Must be invoked on LokiAPI.workQueue
-            guard case HTTP.Error.httpRequestFailed(_, _) = error else { return }
+            guard case HTTP.Error.httpRequestFailed(let statusCode, let json) = error else { return }
+            // Marking all the snodes in the path as unreliable here is aggressive, but otherwise users
+            // can get stuck with a failing path that just refreshes to the same path.
+            let path = paths.first { $0.contains(guardSnode) }
+            path?.forEach { snode in
+                SnodeAPI.handleError(withStatusCode: statusCode, json: json, forSnode: snode) // Intentionally don't throw
+            }
             dropAllPaths() // A snode in the path is bad; retry with a different path
             dropGuardSnode(guardSnode)
         }

SignalServiceKit/src/Loki/API/SnodeAPI.swift

@@ -296,7 +296,7 @@ public final class SnodeAPI : NSObject {
 
     // MARK: Error Handling
     /// - Note: Should only be invoked from `LokiAPI.workQueue` to avoid race conditions.
-    internal static func handleError(withStatusCode statusCode: UInt, json: JSON?, forSnode snode: Snode, associatedWith publicKey: String) -> Error? {
+    internal static func handleError(withStatusCode statusCode: UInt, json: JSON?, forSnode snode: Snode, associatedWith publicKey: String? = nil) -> Error? {
         #if DEBUG
         assertOnQueue(SnodeAPI.workQueue)
         #endif
@@ -307,7 +307,9 @@ public final class SnodeAPI : NSObject {
             print("[Loki] Couldn't reach snode at: \(snode); setting failure count to \(newFailureCount).")
             if newFailureCount >= SnodeAPI.snodeFailureThreshold {
                 print("[Loki] Failure threshold reached for: \(snode); dropping it.")
-                SnodeAPI.dropSnodeFromSwarmIfNeeded(snode, publicKey: publicKey)
+                if let publicKey = publicKey {
+                    SnodeAPI.dropSnodeFromSwarmIfNeeded(snode, publicKey: publicKey)
+                }
                 SnodeAPI.dropSnodeFromSnodePool(snode)
                 SnodeAPI.snodeFailureCount[snode] = 0
             }
@@ -321,8 +323,12 @@ public final class SnodeAPI : NSObject {
             return SnodeAPI.SnodeAPIError.clockOutOfSync
         case 421:
             // The snode isn't associated with the given public key anymore
-            print("[Loki] Invalidating swarm for: \(publicKey).")
-            SnodeAPI.dropSnodeFromSwarmIfNeeded(snode, publicKey: publicKey)
+            if let publicKey = publicKey {
+                print("[Loki] Invalidating swarm for: \(publicKey).")
+                SnodeAPI.dropSnodeFromSwarmIfNeeded(snode, publicKey: publicKey)
+            } else {
+                print("[Loki] Got a 421 without an associated public key.")
+            }
         case 432:
             // The proof of work difficulty is too low
             if let powDifficulty = json?["difficulty"] as? UInt {