Relax SwiftLint version logic to fallback to latest version

Author: mokagio

Package.swift

@@ -15,7 +15,7 @@ let package = Package(
         // See https://github.com/erikdoe/ocmock/issues/500#issuecomment-1002700625
         .package(url: "https://github.com/erikdoe/ocmock", revision: "afd2c6924e8a36cb872bc475248b978f743c6050"),
         .package(url: "https://github.com/Quick/Quick", from: "6.0.0"),
-        .package(url: "https://github.com/realm/SwiftLint", .exactItem(loadSwiftLintVersion()))
+        swiftLintPlugin()
     ],
     targets: [
         .target(
@@ -62,25 +62,42 @@ let package = Package(
     ]
 )
 
-func loadSwiftLintVersion() -> Version {
+func swiftLintPlugin() -> PackageDescription.Package.Dependency {
+    let url = "https://github.com/realm/SwiftLint"
+
+    // Swift can access and read the config file with the current logic only within the package repo.
+    // This is, the check will fail when 'swift build' attempts to resolve the package as a dependency.
+    // To workaround this limitation, we fall back to the latest version of the plugin when the config file read fails.
+    // This should be safe to do, given the SwiftLint plugin is only used in development.
+    guard let version = loadSwiftLintVersion() else {
+        return .package(url: url, from: "0.54.0")
+    }
+
+    return .package(url: url, .exactItem(version))
+}
+
+func loadSwiftLintVersion() -> Version? {
     let swiftLintConfigURL = URL(fileURLWithPath: #file)
         .deletingLastPathComponent()
         .appendingPathComponent(".swiftlint.yml")
 
     guard let yamlString = try? String(contentsOf: swiftLintConfigURL) else {
-        fatalError("Failed to read SwiftLint config file at \(swiftLintConfigURL).")
+        print("[!] Failed to read SwiftLint config file at \(swiftLintConfigURL).")
+        return .none
     }
 
     guard let versionLine = yamlString.components(separatedBy: .newlines)
         .first(where: { $0.contains("swiftlint_version") }) else {
-        fatalError("SwiftLint version not found in YAML file.")
+        print("[!] SwiftLint version not found in YAML file.")
+        return .none
     }
 
     // Assumes the format `swiftlint_version: <version>`
     guard let version = Version(versionLine.components(separatedBy: ":")
         .last?
         .trimmingCharacters(in: .whitespaces) ?? "") else {
-        fatalError("Failed to extract SwiftLint version.")
+        print("[!] Failed to extract SwiftLint version.")
+        return .none
     }
 
     return version