Warn on unrecognized keys in target dictionaries

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Next Version
 
 ### Added
+- Added a warning when a target dictionary contains keys not recognized by `Target.init`, helping catch typos such as `resources` instead of `sources` #1660 @FawwazLawal
 - Added `buildArchitectures` to scheme build options and target schemes, to control Xcode's "Override Architectures" scheme setting #1642 @arhxam
 - Added FAQ documentation on how to add an Xcode capability, such as In-App Purchase #1644 @Hokila
 - Added `xcode26_3` `projectFormat` option for the Xcode 26.3 project format (`objectVersion = 100`) #1648 @Raymondriter

Sources/ProjectSpec/SpecLoader.swift

@@ -51,7 +51,17 @@ public class SpecLoader {
 private extension Dictionary where Key == String, Value: Any {
 
     func validateWarnings() throws {
-        let errors: [SpecValidationError.ValidationError] = []
+        var errors: [SpecValidationError.ValidationError] = []
+
+        if let targets = self["targets"] as? [String: Any] {
+            for (targetName, value) in targets.sorted(by: { $0.key < $1.key }) {
+                if let targetDict = value as? [String: Any] {
+                    for key in targetDict.keys.sorted() where !Target.recognizedKeys.contains(key) {
+                        errors.append(.unrecognizedTargetKey(target: targetName, key: key))
+                    }
+                }
+            }
+        }
 
         if !errors.isEmpty {
             throw SpecValidationError(errors: errors)

Sources/ProjectSpec/SpecValidationError.swift

@@ -44,6 +44,7 @@ public struct SpecValidationError: Error, CustomStringConvertible {
         case invalidPluginPackageReference(plugin: String, package: String)
         case emptySourcePath(target: String)
         case invalidProjectFormat(String)
+        case unrecognizedTargetKey(target: String, key: String)
 
         public var description: String {
             switch self {
@@ -116,6 +117,9 @@ public struct SpecValidationError: Error, CustomStringConvertible {
             case let .invalidProjectFormat(projectFormat):
                 let validValues = ProjectFormat.allCases.map(\.rawValue).joined(separator: ", ")
                 return "Invalid projectFormat \(projectFormat.quoted). Valid values are: \(validValues)"
+            case let .unrecognizedTargetKey(target, key):
+                let validKeys = Target.recognizedKeys.sorted().joined(separator: ", ")
+                return "Target \(target.quoted) has unrecognized key \(key.quoted). Valid target keys are: \(validKeys)"
             }
         }
     }

Sources/ProjectSpec/Target.swift

@@ -273,6 +273,23 @@ extension LegacyTarget: JSONEncodable {
     }
 }
 
+extension Target {
+
+    public static let recognizedKeys: Set<String> = [
+        "name", "productName", "type", "supportedDestinations",
+        "isMultiPlatformTarget", "platform", "deploymentTarget",
+        "settings", "configFiles", "sources", "dependencies",
+        "buildToolPlugins", "info", "entitlements",
+        "transitivelyLinkDependencies", "directlyEmbedCarthageDependencies",
+        "requiresObjCLinking", "preBuildScripts", "prebuildScripts",
+        "postCompileScripts", "postBuildScripts", "postbuildScripts",
+        "buildRules", "scheme", "legacy", "attributes",
+        "onlyCopyFilesOnInstall", "putResourcesBeforeSourcesBuildPhase",
+        "templates", "templateAttributes",
+        "platformPrefix", "platformSuffix",
+    ]
+}
+
 extension Target: NamedJSONDictionaryConvertible {
 
     public init(name: String, jsonDictionary: JSONDictionary) throws {

Tests/ProjectSpecTests/SpecLoadingTests.swift

@@ -423,6 +423,58 @@ class SpecLoadingTests: XCTestCase {
                     throw failure("Expected to not throw a validation error. Got: \(error)")
                 }
             }
+
+            $0.it("warns on unrecognized target keys") {
+                let dictionary: [String: Any] = [
+                    "name": "TestUnrecognizedKey",
+                    "targets": [
+                        "MyApp": [
+                            "type": "application",
+                            "platform": "iOS",
+                            "resources": ["Resources/**"],
+                        ],
+                    ],
+                ]
+                try? Yams.dump(object: dictionary).write(toFile: path.string, atomically: true, encoding: .utf8)
+                let specLoader = SpecLoader(version: "1.1.0")
+                _ = try specLoader.loadProject(path: path)
+                do {
+                    try specLoader.validateProjectDictionaryWarnings()
+                    throw failure("Expected a warning for unrecognized key \"resources\"")
+                } catch let error as SpecValidationError {
+                    let expected = SpecValidationError.ValidationError.unrecognizedTargetKey(target: "MyApp", key: "resources")
+                    if !error.errors.contains(expected) {
+                        throw failure("Expected warning for unrecognized key \"resources\", got: \(error)")
+                    }
+                    let message = expected.description
+                    if !message.contains("\"resources\"") || !message.contains("Valid target keys are:") {
+                        throw failure("Expected message to name the key and list valid keys, got: \(message)")
+                    }
+                }
+            }
+
+            $0.it("does not warn on recognized target keys") {
+                let dictionary: [String: Any] = [
+                    "name": "TestRecognizedKeys",
+                    "targets": [
+                        "MyApp": [
+                            "type": "application",
+                            "platform": "iOS",
+                            "sources": ["Sources"],
+                            "dependencies": [],
+                            "settings": ["SWIFT_VERSION": "5"],
+                        ],
+                    ],
+                ]
+                try? Yams.dump(object: dictionary).write(toFile: path.string, atomically: true, encoding: .utf8)
+                let specLoader = SpecLoader(version: "1.1.0")
+                _ = try specLoader.loadProject(path: path)
+                do {
+                    try specLoader.validateProjectDictionaryWarnings()
+                } catch {
+                    throw failure("Unexpected warning for recognized keys: \(error)")
+                }
+            }
         }
     }