Make WordPressOrgXMLRPCApiError conform to CustomNSError

CHANGELOG.md

@@ -30,6 +30,24 @@ _None._
 
 -->
 
+## Unreleased
+
+### Breaking Changes
+
+- The Objective-C-visible `WordPressOrgXMLRPCError` `enum` has been renamed to `WordPressOrgXMLRPCErrorCode`, `WordPressOrgXMLRPCError.Code` in Swift [#790]
+
+### New Features
+
+_None._
+
+### Bug Fixes
+
+_None._
+
+### Internal Changes
+
+_None._
+
 ## 17.0.0
 
 ### Breaking Changes

Sources/APIInterface/include/WordPressOrgXMLRPCApiErrorDomain.h

@@ -0,0 +1,9 @@
+#import <Foundation/Foundation.h>
+
+/// Error domain of `NSError` instances that are converted from `WordPressOrgXMLRPCApiError`
+/// and `WordPressAPIError<WordPressOrgXMLRPCApiError>` instances.
+///
+/// This matches the compiler generated value and is used to ensure consistent error domain across error types and SPM or Framework build modes.
+///
+/// See `extension WordPressComRestApiEndpointError: CustomNSError` in CoreAPI package for context.
+static NSString *const _Nonnull WordPressOrgXMLRPCApiErrorDomain = @"WordPressKit.WordPressOrgXMLRPCApiError";

Sources/CoreAPI/WordPressOrgXMLRPCApi.swift

@@ -288,38 +288,6 @@ private class SessionDelegate: NSObject, URLSessionDelegate {
         }
     }
 }
-
-/// Error constants for the WordPress XML-RPC API
-@objc public enum WordPressOrgXMLRPCApiError: Int, Error {
-    /// An error HTTP status code was returned.
-    case httpErrorStatusCode
-    /// The serialization of the request failed.
-    case requestSerializationFailed
-    /// The serialization of the response failed.
-    case responseSerializationFailed
-    /// An unknown error occurred.
-    case unknown
-}
-
-extension WordPressOrgXMLRPCApiError: LocalizedError {
-    public var errorDescription: String? {
-        return NSLocalizedString("There was a problem communicating with the site.", comment: "A general error message shown to the user when there was an API communication failure.")
-    }
-
-    public var failureReason: String? {
-        switch self {
-        case .httpErrorStatusCode:
-            return NSLocalizedString("An HTTP error code was returned.", comment: "A failure reason for when an error HTTP status code was returned from the site.")
-        case .requestSerializationFailed:
-            return NSLocalizedString("The serialization of the request failed.", comment: "A failure reason for when the request couldn't be serialized.")
-        case .responseSerializationFailed:
-            return NSLocalizedString("The serialization of the response failed.", comment: "A failure reason for when the response couldn't be serialized.")
-        case .unknown:
-            return NSLocalizedString("An unknown error occurred.", comment: "A failure reason for when the error that occured wasn't able to be determined.")
-        }
-    }
-}
-
 public struct WordPressOrgXMLRPCApiFault: LocalizedError, HTTPURLResponseProviding {
     public var response: HTTPAPIResponse<Data>
     public let code: Int?
@@ -347,7 +315,13 @@ private extension WordPressAPIResult<HTTPAPIResponse<Data>, WordPressOrgXMLRPCAp
         // https://github.com/wordpress-mobile/WordPressKit-iOS/blob/11.0.0/WordPressKit/WordPressOrgXMLRPCApi.swift#L265
         flatMap { response in
             guard let contentType = response.response.allHeaderFields["Content-Type"] as? String else {
-                return .failure(.unparsableResponse(response: response.response, body: response.body, underlyingError: WordPressOrgXMLRPCApiError.unknown))
+                return .failure(
+                    .unparsableResponse(
+                        response: response.response,
+                        body: response.body,
+                        underlyingError: WordPressOrgXMLRPCApiError(code: .unknown)
+                    )
+                )
             }
 
             if (400..<600).contains(response.response.statusCode) {
@@ -361,7 +335,13 @@ private extension WordPressAPIResult<HTTPAPIResponse<Data>, WordPressOrgXMLRPCAp
             }
 
             guard contentType.hasPrefix("application/xml") || contentType.hasPrefix("text/xml") else {
-                return .failure(.unparsableResponse(response: response.response, body: response.body, underlyingError: WordPressOrgXMLRPCApiError.unknown))
+                return .failure(
+                    .unparsableResponse(
+                        response: response.response,
+                        body: response.body,
+                        underlyingError: WordPressOrgXMLRPCApiError(code: .unknown)
+                    )
+                )
             }
 
             guard let decoder = WPXMLRPCDecoder(data: response.body) else {
@@ -391,7 +371,7 @@ private extension WordPressAPIError where EndpointError == WordPressOrgXMLRPCApi
     /// Convert to NSError for backwards compatiblity.
     ///
     /// Some Objective-C code in the WordPress app checks domain of the errors returned by `WordPressOrgXMLRPCApi`,
-    /// which can be WordPressOrgXMLRPCApiError or WPXMLRPCFaultErrorDomain.
+    /// which can be `WordPressOrgXMLRPCApiError` or `WPXMLRPCFaultErrorDomain`.
     ///
     /// Swift code should avoid dealing with NSError instances. Instead, they should use the strongly typed
     /// `WordPressAPIError<WordPressOrgXMLRPCApiFault>`.
@@ -413,7 +393,7 @@ private extension WordPressAPIError where EndpointError == WordPressOrgXMLRPCApi
             data = fault.response.body
             statusCode = nil
         case let .unacceptableStatusCode(response, body):
-            error = WordPressOrgXMLRPCApiError.httpErrorStatusCode as NSError
+            error = WordPressOrgXMLRPCApiError(code: .httpErrorStatusCode) as NSError
             data = body
             statusCode = response.statusCode
         case let .unparsableResponse(_, body, underlyingError):
@@ -428,5 +408,4 @@ private extension WordPressAPIError where EndpointError == WordPressOrgXMLRPCApi
 
         return WordPressOrgXMLRPCApi.convertError(error, data: data, statusCode: statusCode)
     }
-
 }

Sources/CoreAPI/WordPressOrgXMLRPCApiError+NSErrorBridge.swift

@@ -0,0 +1,14 @@
+import Foundation
+#if SWIFT_PACKAGE
+import APIInterface
+#endif
+
+/// See `extension WordPressComRestApiEndpointError: CustomNSError` for documentation and rationale.
+extension WordPressOrgXMLRPCApiError: CustomNSError {
+
+    public static let errorDomain = WordPressOrgXMLRPCApiErrorDomain
+
+    public var errorCode: Int { code.rawValue }
+
+    public var errorUserInfo: [String: Any] { [:] }
+}

Sources/CoreAPI/WordPressOrgXMLRPCApiError.swift

@@ -0,0 +1,40 @@
+import Foundation
+
+public struct WordPressOrgXMLRPCApiError: Error {
+
+    /// Error constants for the WordPress XML-RPC API
+    @objc public enum Code: Int, CaseIterable {
+        /// An error HTTP status code was returned.
+        case httpErrorStatusCode
+        /// The serialization of the request failed.
+        case requestSerializationFailed
+        /// The serialization of the response failed.
+        case responseSerializationFailed
+        /// An unknown error occurred.
+        case unknown
+    }
+
+    let code: Code
+}
+
+extension WordPressOrgXMLRPCApiError: LocalizedError {
+    public var errorDescription: String? {
+        return NSLocalizedString(
+            "There was a problem communicating with the site.",
+            comment: "A general error message shown to the user when there was an API communication failure."
+        )
+    }
+
+    public var failureReason: String? {
+        switch code {
+        case .httpErrorStatusCode:
+            return NSLocalizedString("An HTTP error code was returned.", comment: "A failure reason for when an error HTTP status code was returned from the site.")
+        case .requestSerializationFailed:
+            return NSLocalizedString("The serialization of the request failed.", comment: "A failure reason for when the request couldn't be serialized.")
+        case .responseSerializationFailed:
+            return NSLocalizedString("The serialization of the response failed.", comment: "A failure reason for when the response couldn't be serialized.")
+        case .unknown:
+            return NSLocalizedString("An unknown error occurred.", comment: "A failure reason for when the error that occured wasn't able to be determined.")
+        }
+    }
+}

Sources/WordPressKit/WordPressKit.h

@@ -11,6 +11,7 @@ FOUNDATION_EXPORT const unsigned char WordPressKitVersionString[];
 #import <WordPressKit/WordPressComRESTAPIVersion.h>
 #import <WordPressKit/WordPressComRESTAPIVersionedPathBuilder.h>
 #import <WordPressKit/WordPressComRestApiErrorDomain.h>
+#import <WordPressKit/WordPressOrgXMLRPCApiErrorDomain.h>
 
 #import <WordPressKit/ServiceRemoteWordPressComREST.h>
 #import <WordPressKit/ServiceRemoteWordPressXMLRPC.h>

Tests/CoreAPITests/WordPressComRestApiTests+Error.swift

@@ -21,5 +21,4 @@ class WordPressComRestApiErrorTests: XCTestCase {
     func testErrorDomain() {
         XCTAssertEqual(WordPressComRestApiErrorDomain, WordPressComRestApiEndpointError.errorDomain)
     }
-
 }

Tests/CoreAPITests/WordPressOrgXMLRPCApiErrorTests.swift

@@ -0,0 +1,25 @@
+#if SWIFT_PACKAGE
+import APIInterface
+@testable import CoreAPI
+#else
+@testable import WordPressKit
+#endif
+import XCTest
+
+class WordPressOrgXMLRPCApiErrorTests: XCTestCase {
+
+    func testNSErrorBridging() throws {
+        for error in WordPressOrgXMLRPCApiError.Code.allCases {
+            let xmlRPCError = try XCTUnwrap(WordPressOrgXMLRPCApiError(code: error))
+            let apiError = WordPressAPIError.endpointError(xmlRPCError)
+            let newNSError = apiError as NSError
+
+            XCTAssertEqual(newNSError.domain, "WordPressKit.WordPressOrgXMLRPCApiError")
+            XCTAssertEqual(newNSError.code, error.rawValue)
+        }
+    }
+
+    func testErrorDomain() {
+        XCTAssertEqual(WordPressOrgXMLRPCApiErrorDomain, WordPressOrgXMLRPCApiError.errorDomain)
+    }
+}

Tests/CoreAPITests/WordPressOrgXMLRPCApiTests.swift

@@ -2,6 +2,7 @@ import XCTest
 import OHHTTPStubs
 import wpxmlrpc
 #if SWIFT_PACKAGE
+import APIInterface
 @testable import CoreAPI
 import OHHTTPStubsSwift
 #else
@@ -63,13 +64,8 @@ class WordPressOrgXMLRPCApiTests: XCTestCase {
             },
             failure: { (error, _) in
                 expect.fulfill()
-                // When building for SPM, the compiler doesn't generate the domain constant.
-#if SWIFT_PACKAGE
-                XCTAssertEqual(error.domain, "CoreAPI.WordPressOrgXMLRPCApiError")
-#else
                 XCTAssertEqual(error.domain, WordPressOrgXMLRPCApiErrorDomain)
-#endif
-                XCTAssertEqual(error.code, WordPressOrgXMLRPCApiError.httpErrorStatusCode.rawValue)
+                XCTAssertEqual(error.code, WordPressOrgXMLRPCApiError.Code.httpErrorStatusCode.rawValue)
                 XCTAssertEqual(error.localizedFailureReason, "An HTTP error code 404 was returned.")
                 XCTAssertNotNil(error.userInfo[WordPressOrgXMLRPCApi.WordPressOrgXMLRPCApiErrorKeyData as String])
                 XCTAssertNotNil(error.userInfo[WordPressOrgXMLRPCApi.WordPressOrgXMLRPCApiErrorKeyStatusCode as String])
@@ -96,12 +92,7 @@ class WordPressOrgXMLRPCApiTests: XCTestCase {
                 expect.fulfill()
 
                 XCTAssertFalse(error is WordPressOrgXMLRPCApiError)
-                // When building for SPM, the compiler doesn't generate the domain constant.
-#if SWIFT_PACKAGE
-                XCTAssertEqual(error.domain, "CoreAPI.WordPressOrgXMLRPCApiError")
-#else
                 XCTAssertEqual(error.domain, WordPressOrgXMLRPCApiErrorDomain)
-#endif
                 XCTAssertEqual(error.code, 403)
                 XCTAssertEqual(error.localizedFailureReason, "An HTTP error code 403 was returned.")
                 XCTAssertNotNil(error.userInfo[WordPressOrgXMLRPCApi.WordPressOrgXMLRPCApiErrorKeyData as String])
@@ -128,15 +119,10 @@ class WordPressOrgXMLRPCApiTests: XCTestCase {
             failure: { (error, _) in
                 expect.fulfill()
 
-                XCTAssertTrue(error is WordPressOrgXMLRPCApiError)
-                // When building for SPM, the compiler doesn't generate the domain constant.
-#if SWIFT_PACKAGE
-                XCTAssertEqual(error.domain, "CoreAPI.WordPressOrgXMLRPCApiError")
-#else
                 XCTAssertEqual(error.domain, WordPressOrgXMLRPCApiErrorDomain)
-#endif
-                XCTAssertEqual(error.code, WordPressOrgXMLRPCApiError.unknown.rawValue)
-                XCTAssertEqual(error.localizedFailureReason, WordPressOrgXMLRPCApiError.unknown.failureReason)
+                let errorUnknonw = WordPressOrgXMLRPCApiError(code: .unknown)
+                XCTAssertEqual(error.code, errorUnknonw.code.rawValue)
+                XCTAssertEqual(error.localizedFailureReason, errorUnknonw.failureReason)
                 XCTAssertNotNil(error.userInfo[WordPressOrgXMLRPCApi.WordPressOrgXMLRPCApiErrorKeyData as String])
                 XCTAssertNil(error.userInfo[WordPressOrgXMLRPCApi.WordPressOrgXMLRPCApiErrorKeyStatusCode as String])
             }