Thread networking errors and add custom error descriptions (#2324)

* Better network error descriptions

* localized descriptions for custom errors

Author: rnystrom

Classes/Repository/RepositoryCodeDirectoryViewController.swift

@@ -9,6 +9,7 @@
 import UIKit
 import IGListKit
 import TUSafariActivity
+import Squawk
 
 final class RepositoryCodeDirectoryViewController: BaseListViewController<NSNumber>,
 BaseListViewControllerDataSource,
@@ -123,7 +124,8 @@ RepositoryBranchUpdatable {
         path: path.path
         ) { [weak self] (result) in
             switch result {
-            case .error:
+            case .error(let error):
+                Squawk.show(error: error)
                 self?.error(animated: trueUnlessReduceMotionEnabled)
             case .success(let files):
                 self?.files = files

Classes/Repository/RepositoryOverviewViewController.swift

@@ -9,6 +9,7 @@
 import UIKit
 import IGListKit
 import GitHubAPI
+import Squawk
 
 class HackScrollIndicatorInsetsCollectionView: UICollectionView {
     override var scrollIndicatorInsets: UIEdgeInsets {
@@ -97,7 +98,8 @@ RepositoryBranchUpdatable {
                         self?.update(animated: trueUnlessReduceMotionEnabled)
                     }
                 }
-            case .failure:
+            case .failure(let error):
+                Squawk.show(error: error)
                 self?.error(animated: trueUnlessReduceMotionEnabled)
             }
         }

Local Pods/GitHubAPI/GitHubAPI/ClientError.swift

@@ -11,6 +11,17 @@ import Foundation
 public enum ClientError: Error {
     case unauthorized
     case mismatchedInput
-    case outputNil(Error?)
-    case network(Error?)
+}
+
+extension ClientError: LocalizedError {
+
+    public var localizedDescription: String {
+        switch self {
+        case .unauthorized:
+            return NSLocalizedString("You are unauthorized to make this request.", comment: "")
+        case .mismatchedInput:
+            return NSLocalizedString("There was an error parsing this response.", comment: "")
+        }
+    }
+
 }

Local Pods/GitHubAPI/GitHubAPI/Processing.swift

@@ -14,17 +14,17 @@ internal func processResponse<T: Request>(
     response: HTTPURLResponse? = nil,
     error: Error? = nil
     ) -> Result<T.ResponseType> {
+    guard error == nil else {
+        return .failure(error)
+    }
     guard let input = input as? T.ResponseType.InputType else {
         return .failure(ClientError.mismatchedInput)
     }
-    guard error == nil else {
-        return .failure(ClientError.network(error))
-    }
     do {
         let output = try T.ResponseType(input: input, response: response)
         return .success(output)
     } catch {
-        return .failure(ClientError.outputNil(error))
+        return .failure(error)
     }
 }