Make Articles module adhere to strict Swift concurrency.

Articles/Package.swift

@@ -2,22 +2,26 @@
 import PackageDescription
 
 let package = Package(
-    name: "Articles",
+	name: "Articles",
 	platforms: [.macOS(.v14), .iOS(.v17)],
-    products: [
-        .library(
-            name: "Articles",
+	products: [
+		.library(
+			name: "Articles",
 			type: .dynamic,
-            targets: ["Articles"]),
-    ],
-    dependencies: [
+			targets: ["Articles"]),
+	],
+	dependencies: [
 		.package(url: "https://github.com/Ranchero-Software/RSCore.git", .upToNextMinor(from: "1.0.0")),
-    ],
-    targets: [
-        .target(
-            name: "Articles",
+	],
+	targets: [
+		.target(
+			name: "Articles",
 			dependencies: [
 				"RSCore"
-			]),
+			],
+			swiftSettings: [
+				.enableExperimentalFeature("StrictConcurrency")
+			]
+		),
 	]
 )

Articles/Sources/Articles/Article.swift

@@ -53,7 +53,7 @@ public struct Article: Hashable {
 	}
 
 	public static func calculatedArticleID(feedID: String, uniqueID: String) -> String {
-		return databaseIDWithString("\(feedID) \(uniqueID)")
+		return DatabaseIDCache.shared.databaseIDWithString("\(feedID) \(uniqueID)")
 	}
 
 	// MARK: - Hashable

Articles/Sources/Articles/Author.swift

@@ -33,7 +33,7 @@ public struct Author: Codable, Hashable {
 			s += url ?? ""
 			s += avatarURL ?? ""
 			s += emailAddress ?? ""
-			self.authorID = databaseIDWithString(s)
+			self.authorID = DatabaseIDCache.shared.databaseIDWithString(s)
 		}
 	}
 

Articles/Sources/Articles/DatabaseID.swift

@@ -9,23 +9,30 @@
 import Foundation
 import RSCore
 
-// MD5 works because:
-// * It’s fast
-// * Collisions aren’t going to happen with feed data
+class DatabaseIDCache: @unchecked Sendable {
 
-private var databaseIDCache = [String: String]()
-private var databaseIDCacheLock = NSLock()
-public func databaseIDWithString(_ s: String) -> String {
-    databaseIDCacheLock.lock()
-    defer {
-        databaseIDCacheLock.unlock()
-    }
-	
-	if let identifier = databaseIDCache[s] {
+	static let shared = DatabaseIDCache()
+
+	private var databaseIDCache = [String: String]()
+	private let databaseIDCacheLock = NSLock()
+
+	/// Generates — or retrieves from cache — a database-suitable ID based on a String.
+	func databaseIDWithString(_ s: String) -> String {
+
+		databaseIDCacheLock.lock()
+		defer {
+			databaseIDCacheLock.unlock()
+		}
+
+		if let identifier = databaseIDCache[s] {
+			return identifier
+		}
+
+		// MD5 works because:
+		// * It’s fast
+		// * Collisions aren’t going to happen with feed data
+		let identifier = s.md5String
+		databaseIDCache[s] = identifier
 		return identifier
 	}
-	
-	let identifier = s.md5String
-	databaseIDCache[s] = identifier
-	return identifier
 }