Make ChannelError and NIOConnectionError conform to CustomStringConvertible

Sources/NIOCore/Channel.swift

@@ -427,6 +427,47 @@ extension ChannelError {
 
 extension ChannelError: Equatable {}
 
+extension ChannelError: CustomStringConvertible {
+    public var description: String {
+         switch self {
+         case .connectPending:
+             "Connect pending"
+         case let .connectTimeout(value):
+             "Connect timeout (\(value))"
+         case .operationUnsupported:
+             "Operation unsupported"
+         case .ioOnClosedChannel:
+             "I/O on closed channel"
+         case .alreadyClosed:
+             "Already closed"
+         case .outputClosed:
+             "Output closed"
+         case .inputClosed:
+             "Input closed"
+         case .eof:
+             "End of file"
+         case .writeMessageTooLarge:
+             "Write message too large"
+         case .writeHostUnreachable:
+             "Write host unreachable"
+         case .unknownLocalAddress:
+             "Unknown local address"
+         case .badMulticastGroupAddressFamily:
+             "Bad multicast group address family"
+         case .badInterfaceAddressFamily:
+             "Bad interface address family"
+         case let .illegalMulticastAddress(address):
+             "Illegal multicast address \(address)"
+         case let .multicastNotSupported(interface):
+             "Multicast not supported on interface \(interface)"
+         case .inappropriateOperationForState:
+             "Inappropriate operation for state"
+         case .unremovableHandler:
+             "Unremovable handler"
+         }
+    }
+}
+
 /// The removal of a `ChannelHandler` using `ChannelPipeline.removeHandler` has been attempted more than once.
 public struct NIOAttemptedToRemoveHandlerMultipleTimesError: Error {}
 

Sources/NIOPosix/HappyEyeballs.swift

@@ -70,6 +70,28 @@ public struct NIOConnectionError: Error {
     }
 }
 
+extension NIOConnectionError: CustomStringConvertible {
+    public var description: String {
+        if let dnsError = (dnsAError ?? dnsAAAAError) {
+             return "DNS error: \(dnsError.localizedDescription)"
+         }
+
+         if !connectionErrors.isEmpty {
+             let descriptions = connectionErrors.map {
+                 if let channelError = $0.error as? ChannelError {
+                     channelError.description
+                 } else {
+                     $0.error.localizedDescription
+                 }
+             }
+
+             return "Connection errors: \(descriptions.joined(separator: ", "))"
+         }
+
+         return "Unknown error"
+     }
+}
+
 /// A simple iterator that manages iterating over the possible targets.
 ///
 /// This iterator knows how to merge together the A and AAAA records in a sensible way: