Throw error when unable to satisfy relay constraints

5 files changed, 22 insertions, 18 deletions

diff --git a/ios/MullvadVPN/RelaySelector.swift b/ios/MullvadVPN/RelaySelector.swift
index 5e7492ca16..c29c8ccef5 100644
--- a/ios/MullvadVPN/RelaySelector.swift
+++ b/ios/MullvadVPN/RelaySelector.swift
@@ -32,17 +32,23 @@ extension RelaySelectorResult {
     }
 }
 
+struct NoRelaysSatisfyingConstraintsError: LocalizedError {
+    var errorDescription: String? {
+        return "No relays satisfying constraints."
+    }
+}
+
 enum RelaySelector {}
 
 extension RelaySelector {
 
-    static func evaluate(relays: REST.ServerRelaysResponse, constraints: RelayConstraints) -> RelaySelectorResult? {
+    static func evaluate(relays: REST.ServerRelaysResponse, constraints: RelayConstraints) throws -> RelaySelectorResult {
         let filteredRelays = applyConstraints(constraints, relays: Self.parseRelaysResponse(relays))
 
         guard let relayWithLocation = pickRandomRelay(relays: filteredRelays),
               let port = pickRandomPort(rawPortRanges: relays.wireguard.portRanges) else {
-                  return nil
-              }
+            throw NoRelaysSatisfyingConstraintsError()
+        }
 
         let endpoint = MullvadEndpoint(
             ipv4Relay: IPv4Endpoint(
diff --git a/ios/MullvadVPN/SimulatorTunnelProviderHost.swift b/ios/MullvadVPN/SimulatorTunnelProviderHost.swift
index 400aba003c..d523e499fb 100644
--- a/ios/MullvadVPN/SimulatorTunnelProviderHost.swift
+++ b/ios/MullvadVPN/SimulatorTunnelProviderHost.swift
@@ -91,7 +91,7 @@ class SimulatorTunnelProviderHost: SimulatorTunnelProviderDelegate {
         do {
             let tunnelSettings = try SettingsManager.readSettings()
 
-            return RelaySelector.evaluate(
+            return try RelaySelector.evaluate(
                 relays: cachedRelays.relays,
                 constraints: tunnelSettings.relayConstraints
             )
diff --git a/ios/MullvadVPN/TunnelManager/StartTunnelOperation.swift b/ios/MullvadVPN/TunnelManager/StartTunnelOperation.swift
index 081663517d..2ffa3cb9d6 100644
--- a/ios/MullvadVPN/TunnelManager/StartTunnelOperation.swift
+++ b/ios/MullvadVPN/TunnelManager/StartTunnelOperation.swift
@@ -62,12 +62,10 @@ class StartTunnelOperation: ResultOperation<(), TunnelManager.Error> {
     }
 
     private func didReceiveRelays(tunnelSettings: TunnelSettingsV2, cachedRelays: RelayCache.CachedRelays) {
-        let selectorResult = RelaySelector.evaluate(
+        guard let selectorResult = try? RelaySelector.evaluate(
             relays: cachedRelays.relays,
             constraints: tunnelSettings.relayConstraints
-        )
-
-        guard let selectorResult = selectorResult else {
+        ) else {
             finish(completion: .failure(.cannotSatisfyRelayConstraints))
             return
         }
diff --git a/ios/MullvadVPNTests/RelaySelectorTests.swift b/ios/MullvadVPNTests/RelaySelectorTests.swift
index 10dcb8502e..8f997289db 100644
--- a/ios/MullvadVPNTests/RelaySelectorTests.swift
+++ b/ios/MullvadVPNTests/RelaySelectorTests.swift
@@ -11,27 +11,27 @@ import Network
 
 class RelaySelectorTests: XCTestCase {
 
-    func testCountryConstraint() {
+    func testCountryConstraint() throws {
         let constraints = RelayConstraints(location: .only(.country("es")))
 
-        let result = RelaySelector.evaluate(relays: sampleRelays, constraints: constraints)
+        let result = try RelaySelector.evaluate(relays: sampleRelays, constraints: constraints)
 
-        XCTAssertEqual(result?.relay.hostname, "es1-wireguard")
+        XCTAssertEqual(result.relay.hostname, "es1-wireguard")
     }
 
-    func testCityConstraint() {
+    func testCityConstraint() throws {
         let constraints = RelayConstraints(location: .only(.city("se", "got")))
-        let result = RelaySelector.evaluate(relays: sampleRelays, constraints: constraints)
+        let result = try RelaySelector.evaluate(relays: sampleRelays, constraints: constraints)
 
-        XCTAssertEqual(result?.relay.hostname, "se10-wireguard")
+        XCTAssertEqual(result.relay.hostname, "se10-wireguard")
     }
 
-    func testHostnameConstraint() {
+    func testHostnameConstraint() throws {
         let constraints = RelayConstraints(location: .only(.hostname("se", "sto", "se6-wireguard")))
 
-        let result = RelaySelector.evaluate(relays: sampleRelays, constraints: constraints)
+        let result = try RelaySelector.evaluate(relays: sampleRelays, constraints: constraints)
 
-        XCTAssertEqual(result?.relay.hostname, "se6-wireguard")
+        XCTAssertEqual(result.relay.hostname, "se6-wireguard")
     }
 
 }
diff --git a/ios/PacketTunnel/PacketTunnelProvider.swift b/ios/PacketTunnel/PacketTunnelProvider.swift
index 2e917eb5b1..126ed7b6ae 100644
--- a/ios/PacketTunnel/PacketTunnelProvider.swift
+++ b/ios/PacketTunnel/PacketTunnelProvider.swift
@@ -420,7 +420,7 @@ class PacketTunnelProvider: NEPacketTunnelProvider, TunnelMonitorDelegate {
             throw PacketTunnelProviderError.readRelayCache(error)
         }
 
-        if let selectorResult = RelaySelector.evaluate(
+        if let selectorResult = try? RelaySelector.evaluate(
             relays: cachedRelayList.relays,
             constraints: relayConstraints
         ) {