From 092e31fa21b96c3c987d952349d997efb4dbefe9 Mon Sep 17 00:00:00 2001
From: Red <me@red.to>
Date: Tue, 11 Jun 2024 14:24:07 +0100
Subject: [PATCH 01/12] prepare for StrictConcurrency

---
 Package.resolved                              | 23 ++++++
 Package.swift                                 | 22 ++++--
 Sources/Papyrus/Just.swift                    | 48 ++++++++++++
 Sources/Papyrus/Logger.swift                  |  4 +-
 .../Papyrus/Observers/DirectoryObserver.swift |  6 +-
 Sources/Papyrus/Observers/ObjectChange.swift  |  2 +-
 Sources/Papyrus/PapyrusStore.swift            |  6 +-
 Sources/Papyrus/Queries/CollectionQuery.swift | 46 +++++++----
 Sources/Papyrus/Queries/ObjectQuery.swift     | 76 ++++++++++++++++---
 Tests/Unit/CollectionQueryTests.swift         |  8 +-
 10 files changed, 199 insertions(+), 42 deletions(-)
 create mode 100644 Package.resolved
 create mode 100644 Sources/Papyrus/Just.swift

diff --git a/Package.resolved b/Package.resolved
new file mode 100644
index 0000000..7142500
--- /dev/null
+++ b/Package.resolved
@@ -0,0 +1,23 @@
+{
+  "pins" : [
+    {
+      "identity" : "swift-async-algorithms",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-async-algorithms",
+      "state" : {
+        "revision" : "da4e36f86544cdf733a40d59b3a2267e3a7bbf36",
+        "version" : "1.0.0"
+      }
+    },
+    {
+      "identity" : "swift-collections",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-collections.git",
+      "state" : {
+        "revision" : "ee97538f5b81ae89698fd95938896dec5217b148",
+        "version" : "1.1.1"
+      }
+    }
+  ],
+  "version" : 2
+}
diff --git a/Package.swift b/Package.swift
index 099a3e0..0262a5a 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,8 +1,11 @@
-// swift-tools-version: 5.7
-// The swift-tools-version declares the minimum version of Swift required to build this package.
+// swift-tools-version: 5.8
 
 import PackageDescription
 
+let settings: [SwiftSetting] = [
+    .enableExperimentalFeature("StrictConcurrency")
+]
+
 let package = Package(
     name: "Papyrus",
     platforms: [
@@ -16,18 +19,25 @@ let package = Package(
             name: "Papyrus",
             targets: ["Papyrus"]),
     ],
-    dependencies: [],
+    dependencies: [.package(url: "https://github.com/apple/swift-async-algorithms", from: "1.0.0")],
     targets: [
-        .target(name: "Papyrus"),
+        .target(
+            name: "Papyrus",
+            dependencies: [
+                .product(name: "AsyncAlgorithms", package: "swift-async-algorithms"),
+            ],
+            swiftSettings: settings
+        ),
         .testTarget(
             name: "Unit",
             dependencies: ["Papyrus"],
-            exclude: ["Performance/Supporting Files/Unit.xctestplan"]
+            exclude: ["Supporting Files/Unit.xctestplan"],
+            swiftSettings: settings
         ),
         .testTarget(
             name: "Performance",
             dependencies: ["Papyrus"],
-            exclude: ["Performance/Supporting Files/Performance.xctestplan"]
+            exclude: ["Supporting Files/Performance.xctestplan"]
         ),
     ]
 )
diff --git a/Sources/Papyrus/Just.swift b/Sources/Papyrus/Just.swift
new file mode 100644
index 0000000..dd6fa34
--- /dev/null
+++ b/Sources/Papyrus/Just.swift
@@ -0,0 +1,48 @@
+/// An asynchronous sequence that only emits the provided value once.
+///
+/// ```swift
+/// let stream = Just(1)
+///
+/// for await value in stream {
+///     print(value)
+/// }
+///
+/// // Prints:
+/// // 1
+/// ```
+struct Just<Element>: AsyncSequence {
+    private let element: Element
+    private var emittedElement = false
+    
+    // MARK: Initialization
+    
+    /// Creates an async sequence that emits an element once.
+    /// - Parameters:
+    ///   - element: The element to emit.
+    init(_ element: Element) {
+        self.element = element
+    }
+    
+    // MARK: AsyncSequence
+    
+    /// Creates an async iterator that emits elements of this async sequence.
+    /// - Returns: An instance that conforms to `AsyncIteratorProtocol`.
+    func makeAsyncIterator() -> Self {
+        .init(self.element)
+    }
+}
+
+extension Just: Sendable where Element: Sendable {}
+
+// MARK: AsyncIteratorProtocol
+
+extension Just: AsyncIteratorProtocol {
+    /// Produces the next element in the sequence.
+    /// - Returns: The next element or `nil` if the end of the sequence is reached.
+    mutating func next() async -> Element? {
+        guard !self.emittedElement else { return nil }
+        defer { self.emittedElement = true }
+        
+        return self.element
+    }
+}
diff --git a/Sources/Papyrus/Logger.swift b/Sources/Papyrus/Logger.swift
index ad843fa..01c4237 100644
--- a/Sources/Papyrus/Logger.swift
+++ b/Sources/Papyrus/Logger.swift
@@ -1,5 +1,5 @@
 import Foundation
-import os
+@preconcurrency import os
 
 struct Logger {
     let logLevel: LogLevel
@@ -42,6 +42,8 @@ struct Logger {
     }
 }
 
+extension Logger: Sendable {}
+
 // MARK: Log level
 
 public enum LogLevel: Int, Sendable {
diff --git a/Sources/Papyrus/Observers/DirectoryObserver.swift b/Sources/Papyrus/Observers/DirectoryObserver.swift
index 1b70da4..917ccf4 100644
--- a/Sources/Papyrus/Observers/DirectoryObserver.swift
+++ b/Sources/Papyrus/Observers/DirectoryObserver.swift
@@ -1,6 +1,6 @@
-import Foundation
+@preconcurrency import Foundation
 
-struct DirectoryObserver: Sendable {
+struct DirectoryObserver {
     private let url: URL
     
     // MARK: Initialization
@@ -37,3 +37,5 @@ struct DirectoryObserver: Sendable {
         }
     }
 }
+
+extension DirectoryObserver: Sendable {}
diff --git a/Sources/Papyrus/Observers/ObjectChange.swift b/Sources/Papyrus/Observers/ObjectChange.swift
index 1655bf9..6b12d18 100644
--- a/Sources/Papyrus/Observers/ObjectChange.swift
+++ b/Sources/Papyrus/Observers/ObjectChange.swift
@@ -1,5 +1,5 @@
 public enum ObjectChange<T: Papyrus>: Equatable {
-    case deleted
     case changed(T)
     case created(T)
+    case deleted
 }
diff --git a/Sources/Papyrus/PapyrusStore.swift b/Sources/Papyrus/PapyrusStore.swift
index 7c880f0..9dc6381 100644
--- a/Sources/Papyrus/PapyrusStore.swift
+++ b/Sources/Papyrus/PapyrusStore.swift
@@ -233,8 +233,8 @@ public struct PapyrusStore: Sendable {
         
         try await withThrowingTaskGroup(of: Void.self) { group in
             for object in objects {
-                group.addTask {
-                    try self.delete(id: object.id, of: T.self, touchDirectory: false)
+                group.addTask { [id = object.id] in
+                    try self.delete(id: id, of: T.self, touchDirectory: false)
                 }
             }
             
@@ -315,7 +315,7 @@ public struct PapyrusStore: Sendable {
     ///   of stored objects to merge into.
     public func merge<T: Papyrus>(
         objects: [T],
-        into filter: @escaping (_ object: T) -> Bool
+        into filter: @Sendable @escaping (T) -> Bool
     ) async throws where T: Sendable {
         let objectIDs = objects.map(\.id)
         let objectsToDelete = self.objects(type: T.self)
diff --git a/Sources/Papyrus/Queries/CollectionQuery.swift b/Sources/Papyrus/Queries/CollectionQuery.swift
index 8e2c233..9e66545 100644
--- a/Sources/Papyrus/Queries/CollectionQuery.swift
+++ b/Sources/Papyrus/Queries/CollectionQuery.swift
@@ -1,27 +1,34 @@
+import AsyncAlgorithms
 import Foundation
 
 /// `PapyrusStore.CollectionQuery<T>` is a mechanism for querying `Papyrus` objects.
-public class CollectionQuery<T> where T: Papyrus {
-    public typealias OnFilter = (T) -> Bool
-    public typealias OnSort = (T, T) -> Bool
+public struct CollectionQuery<T> where T: Papyrus {
+    public typealias OnFilter = @Sendable (T) -> Bool
+    public typealias OnSort = @Sendable (T, T) -> Bool
     
     // Private
     private let decoder: JSONDecoder = .init()
     private let directoryURL: URL
-    private let fileManager = FileManager.default
-    private var filter: OnFilter?
+    private let filter: OnFilter?
     private let logger: Logger
-    private var sort: OnSort?
+    private let sort: OnSort?
     
     // MARK: Initialization
     
-    init(directoryURL: URL, logLevel: LogLevel = .off) {
+    init(
+        directoryURL: URL,
+        filter: OnFilter? = nil,
+        logLevel: LogLevel = .off,
+        sort: OnSort? = nil
+    ) {
         self.directoryURL = directoryURL
+        self.filter = filter
         self.logger = Logger(
             subsystem: "com.reddavis.PapyrusStore",
             category: "CollectionQuery",
             logLevel: logLevel
         )
+        self.sort = sort
     }
     
     // MARK: API
@@ -36,19 +43,25 @@ public class CollectionQuery<T> where T: Papyrus {
     /// Apply a filter to the query.
     /// - Parameter onFilter: The filter to be applied.
     /// - Returns: The query item.
-    @discardableResult
     public func filter(_ onFilter: @escaping OnFilter) -> Self {
-        self.filter = onFilter
-        return self
+        .init(
+            directoryURL: directoryURL,
+            filter: onFilter,
+            logLevel: logger.logLevel,
+            sort: sort
+        )
     }
     
     /// Apply a sort to the query.
     /// - Parameter onSort: The sort to be applied.
     /// - Returns: The query item.
-    @discardableResult
     public func sort(_ onSort: @escaping OnSort) -> Self {
-        self.sort = onSort
-        return self
+        .init(
+            directoryURL: directoryURL,
+            filter: filter,
+            logLevel: logger.logLevel,
+            sort: onSort
+        )
     }
     
     /// Observe changes to the query.
@@ -67,13 +80,14 @@ public class CollectionQuery<T> where T: Papyrus {
     
     private func fetchObjects() -> [T] {
         do {
-            let filenames = try self.fileManager.contentsOfDirectory(atPath: self.directoryURL.path)
+            let fileManager = FileManager.default
+            let filenames = try fileManager.contentsOfDirectory(atPath: self.directoryURL.path)
             return filenames.reduce(into: [(Date, T)]()) { result, filename in
                 do {
                     let url = self.directoryURL.appendingPathComponent(filename)
                     let data = try Data(contentsOf: url)
                     let model = try self.decoder.decode(T.self, from: data)
-                    let creationDate = try self.fileManager.attributesOfItem(
+                    let creationDate = try fileManager.attributesOfItem(
                         atPath: url.path
                     )[.creationDate] as? Date ?? .now
                     result.append((creationDate, model))
@@ -95,6 +109,8 @@ public class CollectionQuery<T> where T: Papyrus {
     }
 }
 
+extension CollectionQuery: Sendable {}
+
 // MARK: Sequence
 
 extension Sequence {
diff --git a/Sources/Papyrus/Queries/ObjectQuery.swift b/Sources/Papyrus/Queries/ObjectQuery.swift
index fcd90da..17f283c 100644
--- a/Sources/Papyrus/Queries/ObjectQuery.swift
+++ b/Sources/Papyrus/Queries/ObjectQuery.swift
@@ -1,10 +1,10 @@
+import AsyncAlgorithms
 import Foundation
 
 /// `ObjectQuery<T>` is a mechanism for querying a single `Papyrus` object.
-public class ObjectQuery<T: Papyrus> {
+public struct ObjectQuery<T: Papyrus> {
     private let decoder: JSONDecoder = .init()
     private let directoryURL: URL
-    private let fileManager = FileManager.default
     private let filename: String
     private let logger: Logger
     
@@ -39,14 +39,18 @@ public class ObjectQuery<T: Papyrus> {
         
     /// Observe changes to the query via an async stream.
     /// - Returns: A `AsyncThrowingStream` instance.
-    public func observe() -> AsyncThrowingStream<ObjectChange<T>, Error> {
-        var previousResult = self.fetchObject()
+    public func observe() -> AsyncThrowingStream<ObjectChange<T>, Error> where T: Sendable {
         do {
             let observer = try DirectoryObserver(url: self.directoryURL)
-            return observer.observe()
-                .compactMap { _ in
-                    let result = self.fetchObject()
-                    defer { previousResult = result }
+            let object = fetchObject()
+            let observerSequence = observer.observe()
+                .map { fetchObject() }
+            
+            return chain(Just(object), observerSequence)
+                .pair()
+                .compactMap { tuple in
+                    let previousResult = tuple.0
+                    let result = tuple.1
                     
                     switch (previousResult, result) {
                     case (.success(let previousModel), .success(let model)) where previousModel != model:
@@ -67,8 +71,9 @@ public class ObjectQuery<T: Papyrus> {
     }
     
     private func fetchObject() -> Result<T, Error> {
+        let fileManager = FileManager.default
         let fileURL = self.directoryURL.appendingPathComponent(self.filename)
-        guard self.fileManager.fileExists(atPath: fileURL.path) else {
+        guard fileManager.fileExists(atPath: fileURL.path) else {
             self.logger.info("Cached data not found. url: \(fileURL)")
             return .failure(NotFoundError())
         }
@@ -82,7 +87,7 @@ public class ObjectQuery<T: Papyrus> {
             do {
                 // Delete cached data
                 self.logger.debug("Deleting old cached data. url: \(fileURL)")
-                try self.fileManager.removeItem(at: fileURL)
+                try fileManager.removeItem(at: fileURL)
             } catch {
                 self.logger.error("Failed deleting old cached data. url: \(fileURL) error: \(error)")
                 return .failure(error)
@@ -92,6 +97,8 @@ public class ObjectQuery<T: Papyrus> {
     }
 }
 
+extension ObjectQuery: Sendable {}
+
 // MARK: Errors
 
 extension ObjectQuery {
@@ -100,3 +107,52 @@ extension ObjectQuery {
         var details: Error
     }
 }
+
+
+extension AsyncSequence {
+    func pair() -> AsyncPairSequence<Self> {
+        AsyncPairSequence(base: self)
+    }
+}
+
+struct AsyncPairSequence<Base: AsyncSequence>: AsyncSequence {
+    typealias AsyncIterator = Iterator
+    typealias Element = (Base.Element, Base.Element)
+    var base: Base
+
+    func makeAsyncIterator() -> AsyncIterator {
+        Iterator(base: base.makeAsyncIterator())
+    }
+}
+
+extension AsyncPairSequence: Sendable where Base: Sendable, Element: Sendable {}
+
+// MARK: Iterator
+
+extension AsyncPairSequence {
+    struct Iterator: AsyncIteratorProtocol {
+        var base: Base.AsyncIterator
+        var lastValue: Base.Element?
+
+        mutating func next() async rethrows -> (Base.Element, Base.Element)? {
+            guard let nextValue = try await base.next() else {
+                return nil
+            }
+            
+            guard let lastValue else {
+                lastValue = nextValue
+                guard let nextNextValue = try await base.next() else {
+                    return nil
+                }
+                
+                lastValue = nextNextValue
+                return (nextValue, nextNextValue)
+            }
+            
+            defer { self.lastValue = nextValue }
+            return (lastValue, nextValue)
+        }
+    }
+}
+
+extension AsyncPairSequence.Iterator: Sendable where Base.AsyncIterator: Sendable, Element: Sendable {}
diff --git a/Tests/Unit/CollectionQueryTests.swift b/Tests/Unit/CollectionQueryTests.swift
index ea4951c..a585b24 100644
--- a/Tests/Unit/CollectionQueryTests.swift
+++ b/Tests/Unit/CollectionQueryTests.swift
@@ -52,9 +52,9 @@ final class CollectionQueryTests: XCTestCase {
     }
     
     func test_filter_whenAppliedToStream() async throws {
-        Task {
+        Task { [directory] in
             try await Task.sleep(for: .milliseconds(10))
-            try FileManager.default.poke(self.directory)
+            try FileManager.default.poke(directory!)
         }
         
         let collection = try await CollectionQuery<ExampleB>(directoryURL: self.directory)
@@ -66,9 +66,9 @@ final class CollectionQueryTests: XCTestCase {
     }
     
     func test_sort_whenAppliedToStream() async throws {
-        Task {
+        Task { [directory] in
             try await Task.sleep(for: .milliseconds(10))
-            try FileManager.default.poke(self.directory)
+            try FileManager.default.poke(directory!)
         }
         
         let collection = try await CollectionQuery<ExampleB>(directoryURL: self.directory)

From 832c178fb7fffa5a4936262a3e942b3e647b4eae Mon Sep 17 00:00:00 2001
From: Red <me@red.to>
Date: Wed, 12 Jun 2024 09:13:49 +0100
Subject: [PATCH 02/12] use the standard logger

---
 Sources/Papyrus/Logger.swift                  | 76 -------------------
 Sources/Papyrus/PapyrusStore.swift            | 22 ++----
 Sources/Papyrus/Queries/CollectionQuery.swift | 10 +--
 Sources/Papyrus/Queries/ObjectQuery.swift     | 10 +--
 Tests/Unit/PapyrusStoreTests.swift            |  2 +-
 5 files changed, 14 insertions(+), 106 deletions(-)
 delete mode 100644 Sources/Papyrus/Logger.swift

diff --git a/Sources/Papyrus/Logger.swift b/Sources/Papyrus/Logger.swift
deleted file mode 100644
index 01c4237..0000000
--- a/Sources/Papyrus/Logger.swift
+++ /dev/null
@@ -1,76 +0,0 @@
-import Foundation
-@preconcurrency import os
-
-struct Logger {
-    let logLevel: LogLevel
-    
-    // Private
-    private let log: OSLog
-    
-    // MARK: Initialziation
-    
-    init(subsystem: String, category: String, logLevel: LogLevel = .info) {
-        self.logLevel = logLevel
-        self.log = OSLog(subsystem: subsystem, category: category)
-    }
-    
-    // MARK: API
-    
-    func info(_ message: String) {
-        self.log("ℹ️ \(message)", level: .info)
-    }
-    
-    func debug(_ message: String) {
-        self.log("🔎 \(message)", level: .debug)
-    }
-    
-    func error(_ message: String) {
-        self.log("⚠️ \(message)", level: .error)
-    }
-
-    func fault(_ message: String) {
-        self.log("🔥 \(message)", level: .fault)
-    }
-    
-    // MARK: Log
-    
-    private func log(_ message: String, level: LogLevel) {
-        guard
-            level >= self.logLevel,
-            let type = level.logType else { return }
-        os_log("%{public}@", log: self.log, type: type, message)
-    }
-}
-
-extension Logger: Sendable {}
-
-// MARK: Log level
-
-public enum LogLevel: Int, Sendable {
-    case info
-    case debug
-    case error
-    case fault
-    case off
-    
-    var logType: OSLogType? {
-        switch self {
-        case .info:
-            return .info
-        case .debug:
-            return .debug
-        case .error:
-            return .error
-        case .fault:
-            return .fault
-        case .off:
-            return nil
-        }
-    }
-}
-
-// MARK: Comparable
-
-extension LogLevel: Comparable {
-    public static func <(lhs: LogLevel, rhs: LogLevel) -> Bool { lhs.rawValue < rhs.rawValue }
-}
diff --git a/Sources/Papyrus/PapyrusStore.swift b/Sources/Papyrus/PapyrusStore.swift
index 9dc6381..02d51b3 100644
--- a/Sources/Papyrus/PapyrusStore.swift
+++ b/Sources/Papyrus/PapyrusStore.swift
@@ -1,4 +1,5 @@
 import Foundation
+import os
 
 /// A `PapyrusStore` is a data store for `Papyrus` conforming objects.
 ///
@@ -15,13 +16,9 @@ public struct PapyrusStore: Sendable {
     
     /// Initialize a new `PapyrusStore` instance persisted at the provided `URL`.
     /// - Parameter url: The `URL` to persist data to.
-    public init(url: URL, logLevel: LogLevel = .off) {
+    public init(url: URL) {
         self.url = url
-        self.logger = Logger(
-            subsystem: "com.reddavis.PapyrusStore",
-            category: "PapyrusStore",
-            logLevel: logLevel
-        )
+        self.logger = Logger(subsystem: "com.reddavis.PapyrusStore", category: "PapyrusStore")
         self.setupDataDirectory()
     }
     
@@ -30,9 +27,9 @@ public struct PapyrusStore: Sendable {
     ///
     /// The default Papyrus Store will persist it's data to a
     /// directory inside Application Support.
-    public init(logLevel: LogLevel = .off) {
+    public init() {
         let url = URL.applicationSupportDirectory.appendingPathComponent("Papyrus", isDirectory: true)
-        self.init(url: url, logLevel: logLevel)
+        self.init(url: url)
     }
     
     // MARK: Store management
@@ -177,8 +174,7 @@ public struct PapyrusStore: Sendable {
     public func object<T: Papyrus, ID: LosslessStringConvertible>(id: ID) -> ObjectQuery<T> {
         ObjectQuery(
             id: id,
-            directoryURL: self.directoryURL(for: T.self),
-            logLevel: self.logger.logLevel
+            directoryURL: self.directoryURL(for: T.self)
         )
     }
     
@@ -191,8 +187,7 @@ public struct PapyrusStore: Sendable {
     public func object<T: Papyrus, ID: LosslessStringConvertible>(id: ID, of type: T.Type) -> ObjectQuery<T> {
         ObjectQuery(
             id: id,
-            directoryURL: self.directoryURL(for: T.self),
-            logLevel: self.logger.logLevel
+            directoryURL: self.directoryURL(for: T.self)
         )
     }
     
@@ -202,8 +197,7 @@ public struct PapyrusStore: Sendable {
     /// - Returns: A `AnyPublisher<[T], Error>` instance.
     public func objects<T: Papyrus>(type: T.Type) -> CollectionQuery<T> {
         CollectionQuery(
-            directoryURL: self.directoryURL(for: T.self),
-            logLevel: self.logger.logLevel
+            directoryURL: self.directoryURL(for: T.self)
         )
     }
     
diff --git a/Sources/Papyrus/Queries/CollectionQuery.swift b/Sources/Papyrus/Queries/CollectionQuery.swift
index 9e66545..82a2c8c 100644
--- a/Sources/Papyrus/Queries/CollectionQuery.swift
+++ b/Sources/Papyrus/Queries/CollectionQuery.swift
@@ -1,5 +1,6 @@
 import AsyncAlgorithms
 import Foundation
+import os
 
 /// `PapyrusStore.CollectionQuery<T>` is a mechanism for querying `Papyrus` objects.
 public struct CollectionQuery<T> where T: Papyrus {
@@ -18,16 +19,11 @@ public struct CollectionQuery<T> where T: Papyrus {
     init(
         directoryURL: URL,
         filter: OnFilter? = nil,
-        logLevel: LogLevel = .off,
         sort: OnSort? = nil
     ) {
         self.directoryURL = directoryURL
         self.filter = filter
-        self.logger = Logger(
-            subsystem: "com.reddavis.PapyrusStore",
-            category: "CollectionQuery",
-            logLevel: logLevel
-        )
+        self.logger = Logger(subsystem: "com.reddavis.PapyrusStore", category: "CollectionQuery")
         self.sort = sort
     }
     
@@ -47,7 +43,6 @@ public struct CollectionQuery<T> where T: Papyrus {
         .init(
             directoryURL: directoryURL,
             filter: onFilter,
-            logLevel: logger.logLevel,
             sort: sort
         )
     }
@@ -59,7 +54,6 @@ public struct CollectionQuery<T> where T: Papyrus {
         .init(
             directoryURL: directoryURL,
             filter: filter,
-            logLevel: logger.logLevel,
             sort: onSort
         )
     }
diff --git a/Sources/Papyrus/Queries/ObjectQuery.swift b/Sources/Papyrus/Queries/ObjectQuery.swift
index 17f283c..c0a2177 100644
--- a/Sources/Papyrus/Queries/ObjectQuery.swift
+++ b/Sources/Papyrus/Queries/ObjectQuery.swift
@@ -1,5 +1,6 @@
 import AsyncAlgorithms
 import Foundation
+import os
 
 /// `ObjectQuery<T>` is a mechanism for querying a single `Papyrus` object.
 public struct ObjectQuery<T: Papyrus> {
@@ -12,16 +13,11 @@ public struct ObjectQuery<T: Papyrus> {
     
     init<ID: LosslessStringConvertible>(
         id: ID,
-        directoryURL: URL,
-        logLevel: LogLevel = .off
+        directoryURL: URL
     ) {
         self.filename = String(id)
         self.directoryURL = directoryURL
-        self.logger = Logger(
-            subsystem: "com.reddavis.PapyrusStore",
-            category: "ObjectQuery",
-            logLevel: logLevel
-        )
+        self.logger = Logger(subsystem: "com.reddavis.PapyrusStore", category: "ObjectQuery")
     }
     
     // MARK: API
diff --git a/Tests/Unit/PapyrusStoreTests.swift b/Tests/Unit/PapyrusStoreTests.swift
index d12be99..2a42b6e 100644
--- a/Tests/Unit/PapyrusStoreTests.swift
+++ b/Tests/Unit/PapyrusStoreTests.swift
@@ -13,7 +13,7 @@ final class PapyrusStoreTests: XCTestCase {
             UUID().uuidString,
             isDirectory: true
         )
-        self.store = PapyrusStore(url: self.directory, logLevel: .info)
+        self.store = PapyrusStore(url: self.directory)
     }
     
     override func tearDown() {

From 595ea8eacaff18213142153ea88cfd4dfae97bb4 Mon Sep 17 00:00:00 2001
From: Red <me@red.to>
Date: Tue, 22 Apr 2025 11:49:47 +0100
Subject: [PATCH 03/12] update swift tools version

---
 Package.swift | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/Package.swift b/Package.swift
index 0262a5a..c30f5a0 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,11 +1,7 @@
-// swift-tools-version: 5.8
+// swift-tools-version: 6.0
 
 import PackageDescription
 
-let settings: [SwiftSetting] = [
-    .enableExperimentalFeature("StrictConcurrency")
-]
-
 let package = Package(
     name: "Papyrus",
     platforms: [
@@ -26,18 +22,16 @@ let package = Package(
             dependencies: [
                 .product(name: "AsyncAlgorithms", package: "swift-async-algorithms"),
             ],
-            swiftSettings: settings
         ),
         .testTarget(
             name: "Unit",
             dependencies: ["Papyrus"],
             exclude: ["Supporting Files/Unit.xctestplan"],
-            swiftSettings: settings
         ),
         .testTarget(
             name: "Performance",
             dependencies: ["Papyrus"],
             exclude: ["Supporting Files/Performance.xctestplan"]
         ),
-    ]
+    ],
 )

From a3cd9b035674a2599a82666751aad7c21d43dd25 Mon Sep 17 00:00:00 2001
From: Red <me@red.to>
Date: Tue, 22 Apr 2025 11:51:07 +0100
Subject: [PATCH 04/12] sendable safe async stream erasure

---
 .../Papyrus/Extensions/AsyncSequence.swift    | 10 -------
 Sources/Papyrus/Extensions/AsyncStream.swift  | 30 ++++++++++++++-----
 .../Extensions/AsyncThrowingStream.swift      | 30 ++++++++++++++-----
 Sources/Papyrus/Observers/ObjectChange.swift  |  2 ++
 Sources/Papyrus/Queries/CollectionQuery.swift |  2 +-
 5 files changed, 49 insertions(+), 25 deletions(-)
 delete mode 100644 Sources/Papyrus/Extensions/AsyncSequence.swift

diff --git a/Sources/Papyrus/Extensions/AsyncSequence.swift b/Sources/Papyrus/Extensions/AsyncSequence.swift
deleted file mode 100644
index 3634faf..0000000
--- a/Sources/Papyrus/Extensions/AsyncSequence.swift
+++ /dev/null
@@ -1,10 +0,0 @@
-// Thanks - https://github.com/pointfreeco/swift-dependencies
-extension AsyncSequence {
-    func eraseToStream() -> AsyncStream<Element> {
-        AsyncStream(self)
-    }
-    
-    func eraseToThrowingStream() -> AsyncThrowingStream<Element, Error> {
-        AsyncThrowingStream(self)
-    }
-}
diff --git a/Sources/Papyrus/Extensions/AsyncStream.swift b/Sources/Papyrus/Extensions/AsyncStream.swift
index 2d14122..3c7eb5c 100644
--- a/Sources/Papyrus/Extensions/AsyncStream.swift
+++ b/Sources/Papyrus/Extensions/AsyncStream.swift
@@ -1,12 +1,28 @@
 // Thanks - https://github.com/pointfreeco/swift-dependencies
-extension AsyncStream {
-    init<S: AsyncSequence>(_ sequence: S) where S.Element == Element {
-        var iterator: S.AsyncIterator?
-        self.init {
-            if iterator == nil {
-                iterator = sequence.makeAsyncIterator()
+extension AsyncStream where Element: Sendable {
+    init<S: AsyncSequence & Sendable>(
+        _ sequence: S
+    ) where S.Element == Element, S.Element: Sendable {
+        self.init { continuation in
+            let task = Task {
+                do {
+                    for try await element in sequence {
+                        continuation.yield(element)
+                    }
+                    continuation.finish()
+                } catch {
+                    continuation.finish()
+                }
+            }
+            continuation.onTermination = { _ in
+                task.cancel()
             }
-            return try? await iterator?.next()
         }
     }
 }
+
+extension AsyncSequence where Self: Sendable, Element: Sendable {
+    func eraseToStream() -> AsyncStream<Element> {
+        AsyncStream(self)
+    }
+}
diff --git a/Sources/Papyrus/Extensions/AsyncThrowingStream.swift b/Sources/Papyrus/Extensions/AsyncThrowingStream.swift
index 4d32a7b..23ffded 100644
--- a/Sources/Papyrus/Extensions/AsyncThrowingStream.swift
+++ b/Sources/Papyrus/Extensions/AsyncThrowingStream.swift
@@ -1,12 +1,28 @@
 // Thanks - https://github.com/pointfreeco/swift-dependencies
-extension AsyncThrowingStream where Failure == Error {
-    init<S: AsyncSequence>(_ sequence: S) where S.Element == Element {
-        var iterator: S.AsyncIterator?
-        self.init {
-            if iterator == nil {
-                iterator = sequence.makeAsyncIterator()
+extension AsyncThrowingStream where Element: Sendable, Failure == Error {
+    init<S: AsyncSequence & Sendable>(
+        _ sequence: S
+    ) where S.Element == Element, S.Element: Sendable {
+        self.init { continuation in
+            let task = Task {
+                do {
+                    for try await element in sequence {
+                        continuation.yield(element)
+                    }
+                    continuation.finish()
+                } catch {
+                    continuation.finish(throwing: error)
+                }
+            }
+            continuation.onTermination = { _ in
+                task.cancel()
             }
-            return try await iterator?.next()
         }
     }
 }
+
+extension AsyncSequence where Self: Sendable, Element: Sendable {
+    func eraseToThrowingStream() -> AsyncThrowingStream<Element, Error> {
+        AsyncThrowingStream(self)
+    }
+}
diff --git a/Sources/Papyrus/Observers/ObjectChange.swift b/Sources/Papyrus/Observers/ObjectChange.swift
index 6b12d18..0fc151a 100644
--- a/Sources/Papyrus/Observers/ObjectChange.swift
+++ b/Sources/Papyrus/Observers/ObjectChange.swift
@@ -3,3 +3,5 @@ public enum ObjectChange<T: Papyrus>: Equatable {
     case created(T)
     case deleted
 }
+
+extension ObjectChange: Sendable where T: Sendable {}
diff --git a/Sources/Papyrus/Queries/CollectionQuery.swift b/Sources/Papyrus/Queries/CollectionQuery.swift
index 82a2c8c..395e63f 100644
--- a/Sources/Papyrus/Queries/CollectionQuery.swift
+++ b/Sources/Papyrus/Queries/CollectionQuery.swift
@@ -60,7 +60,7 @@ public struct CollectionQuery<T> where T: Papyrus {
     
     /// Observe changes to the query.
     /// - Returns: A `AsyncThrowingStream` instance.
-    public func observe() -> AsyncThrowingStream<[T], Error> {
+    public func observe() -> AsyncThrowingStream<[T], Error> where T: Sendable {
         do {
             let observer = try DirectoryObserver(url: self.directoryURL)
             return observer.observe()

From 54ab185ce13af46e50c26e7119a30d7c932266e3 Mon Sep 17 00:00:00 2001
From: Red <me@red.to>
Date: Tue, 22 Apr 2025 12:13:12 +0100
Subject: [PATCH 05/12] follow swift standard

---
 Sources/Papyrus/Fail.swift                    |  8 +-
 Sources/Papyrus/Just.swift                    |  8 +-
 .../Papyrus/Observers/DirectoryObserver.swift | 10 +-
 Sources/Papyrus/Papyrus.swift                 |  5 +-
 Sources/Papyrus/PapyrusStore.swift            | 98 +++++++++----------
 Sources/Papyrus/Queries/CollectionQuery.swift | 37 ++++---
 Sources/Papyrus/Queries/ObjectQuery.swift     | 21 ++--
 7 files changed, 95 insertions(+), 92 deletions(-)

diff --git a/Sources/Papyrus/Fail.swift b/Sources/Papyrus/Fail.swift
index fd674b3..4c7b843 100644
--- a/Sources/Papyrus/Fail.swift
+++ b/Sources/Papyrus/Fail.swift
@@ -34,7 +34,7 @@ struct Fail<Element, Failure>: AsyncSequence, Sendable where Failure: Error {
     /// Creates an async iterator that emits elements of this async sequence.
     /// - Returns: An instance that conforms to `AsyncIteratorProtocol`.
     func makeAsyncIterator() -> Self {
-        .init(error: self.error)
+        .init(error: error)
     }
 }
 
@@ -44,9 +44,9 @@ extension Fail: AsyncIteratorProtocol {
     /// Produces the next element in the sequence.
     /// - Returns: The next element or `nil` if the end of the sequence is reached.
     mutating func next() async throws -> Element? {
-        defer { self.hasThownError = true }
-        guard !self.hasThownError else { return nil }
+        defer { hasThownError = true }
+        guard !hasThownError else { return nil }
         
-        throw self.error
+        throw error
     }
 }
diff --git a/Sources/Papyrus/Just.swift b/Sources/Papyrus/Just.swift
index dd6fa34..8596772 100644
--- a/Sources/Papyrus/Just.swift
+++ b/Sources/Papyrus/Just.swift
@@ -28,7 +28,7 @@ struct Just<Element>: AsyncSequence {
     /// Creates an async iterator that emits elements of this async sequence.
     /// - Returns: An instance that conforms to `AsyncIteratorProtocol`.
     func makeAsyncIterator() -> Self {
-        .init(self.element)
+        .init(element)
     }
 }
 
@@ -40,9 +40,9 @@ extension Just: AsyncIteratorProtocol {
     /// Produces the next element in the sequence.
     /// - Returns: The next element or `nil` if the end of the sequence is reached.
     mutating func next() async -> Element? {
-        guard !self.emittedElement else { return nil }
-        defer { self.emittedElement = true }
+        guard !emittedElement else { return nil }
+        defer { emittedElement = true }
         
-        return self.element
+        return element
     }
 }
diff --git a/Sources/Papyrus/Observers/DirectoryObserver.swift b/Sources/Papyrus/Observers/DirectoryObserver.swift
index 917ccf4..e4f3381 100644
--- a/Sources/Papyrus/Observers/DirectoryObserver.swift
+++ b/Sources/Papyrus/Observers/DirectoryObserver.swift
@@ -1,6 +1,6 @@
-@preconcurrency import Foundation
+import Foundation
 
-struct DirectoryObserver {
+struct DirectoryObserver : Sendable {
     private let url: URL
     
     // MARK: Initialization
@@ -8,8 +8,8 @@ struct DirectoryObserver {
     init(url: URL) throws {
         self.url = url
         
-        if !FileManager.default.fileExists(atPath: self.url.path) {
-            try FileManager.default.createDirectory(at: self.url, withIntermediateDirectories: true)
+        if !FileManager.default.fileExists(atPath: url.path) {
+            try FileManager.default.createDirectory(at: url, withIntermediateDirectories: true)
         }
     }
     
@@ -37,5 +37,3 @@ struct DirectoryObserver {
         }
     }
 }
-
-extension DirectoryObserver: Sendable {}
diff --git a/Sources/Papyrus/Papyrus.swift b/Sources/Papyrus/Papyrus.swift
index efe9a8e..3313736 100644
--- a/Sources/Papyrus/Papyrus.swift
+++ b/Sources/Papyrus/Papyrus.swift
@@ -6,11 +6,12 @@ import Foundation
 /// - `Codable`
 /// - `Equatable`
 /// - `Identifiable where ID: LosslessStringConvertible & Sendable`
-public protocol Papyrus: Codable, Equatable, Identifiable where ID: LosslessStringConvertible & Sendable { }
+public protocol Papyrus: Codable, Equatable, Identifiable
+where ID: LosslessStringConvertible & Sendable { }
 
 // MARK: Helpers
 
 extension Papyrus {
-    var filename: String { String(self.id) }
+    var filename: String { String(id) }
     var typeDescription: String { String(describing: type(of: self)) }
 }
diff --git a/Sources/Papyrus/PapyrusStore.swift b/Sources/Papyrus/PapyrusStore.swift
index 02d51b3..6e0679e 100644
--- a/Sources/Papyrus/PapyrusStore.swift
+++ b/Sources/Papyrus/PapyrusStore.swift
@@ -19,7 +19,7 @@ public struct PapyrusStore: Sendable {
     public init(url: URL) {
         self.url = url
         self.logger = Logger(subsystem: "com.reddavis.PapyrusStore", category: "PapyrusStore")
-        self.setupDataDirectory()
+        setupDataDirectory()
     }
     
     /// Initialize a new `PapyrusStore` instance with the default
@@ -36,9 +36,9 @@ public struct PapyrusStore: Sendable {
     
     private func setupDataDirectory() {
         do {
-            try self.createDirectoryIfNeeded(at: self.url)
+            try createDirectoryIfNeeded(at: url)
         } catch {
-            self.logger.fault("Unable to create store directory: \(error)")
+            logger.fault("Unable to create store directory: \(error)")
         }
     }
     
@@ -46,39 +46,39 @@ public struct PapyrusStore: Sendable {
     ///
     /// This will destroy and then rebuild the store's directory.
     public func reset() throws {
-        try self.fileManager.removeItem(at: self.url)
-        self.setupDataDirectory()
+        try fileManager.removeItem(at: url)
+        setupDataDirectory()
     }
     
     // MARK: File management
     
     private func fileURL<ID: LosslessStringConvertible>(for typeDescription: String, id: ID) -> URL {
-        self.fileURL(for: typeDescription, filename: String(id))
+        fileURL(for: typeDescription, filename: String(id))
     }
     
     private func fileURL(for typeDescription: String, filename: String) -> URL {
-        self.directoryURL(for: typeDescription).appendingPathComponent(filename)
+        directoryURL(for: typeDescription).appendingPathComponent(filename)
     }
     
     private func directoryURL<T>(for type: T.Type) -> URL {
-        self.directoryURL(for: String(describing: type))
+        directoryURL(for: String(describing: type))
     }
     
     private func directoryURL(for typeDescription: String) -> URL {
-        self.url.appendingPathComponent(typeDescription, isDirectory: true)
+        url.appendingPathComponent(typeDescription, isDirectory: true)
     }
     
     private func createDirectoryIfNeeded<T>(for type: T.Type) throws {
-        try self.createDirectoryIfNeeded(for: String(describing: type))
+        try createDirectoryIfNeeded(for: String(describing: type))
     }
     
     private func createDirectoryIfNeeded(for typeDescription: String) throws {
-        try self.createDirectoryIfNeeded(at: self.directoryURL(for: typeDescription))
+        try createDirectoryIfNeeded(at: directoryURL(for: typeDescription))
     }
     
     private func createDirectoryIfNeeded(at url: URL) throws {
         var isDirectory = ObjCBool(false)
-        let exists = self.fileManager.fileExists(atPath: url.path, isDirectory: &isDirectory)
+        let exists = fileManager.fileExists(atPath: url.path, isDirectory: &isDirectory)
         
         // All good - directory already exists.
         if isDirectory.boolValue && exists { return }
@@ -87,12 +87,12 @@ public struct PapyrusStore: Sendable {
         else if !isDirectory.boolValue && exists { throw SetupError.fileExistsInDirectoryURL(url) }
         
         // Create directory
-        try self.fileManager.createDirectory(at: url, withIntermediateDirectories: true, attributes: nil)
-        self.logger.debug("Created directory: \(url.absoluteString)")
+        try fileManager.createDirectory(at: url, withIntermediateDirectories: true, attributes: nil)
+        logger.debug("Created directory: \(url.absoluteString)")
     }
     
     private func setCreatedAt(_ timestamp: Date, for url: URL) throws {
-        try self.fileManager.setAttributes(
+        try fileManager.setAttributes(
             [.creationDate: timestamp],
             ofItemAtPath: url.path
         )
@@ -103,28 +103,28 @@ public struct PapyrusStore: Sendable {
     /// Saves the object to the store.
     /// - Parameter object: The object to save.
     public func save<T: Papyrus>(_ object: T) throws {
-        try self.save(object, touchDirectory: true)
+        try save(object, touchDirectory: true)
     }
     
     private func save<T: Papyrus>(_ object: T, touchDirectory: Bool) throws {
         do {
-            try self.createDirectoryIfNeeded(for: T.self)
+            try createDirectoryIfNeeded(for: T.self)
             
-            let data = try self.encoder.encode(object)
-            let url = self.fileURL(for: object.typeDescription, filename: object.filename)
+            let data = try encoder.encode(object)
+            let url = fileURL(for: object.typeDescription, filename: object.filename)
             try data.write(to: url)
-            self.logger.debug("Saved object \(object.typeDescription). filename: \(object.filename)]")
+            logger.debug("Saved object \(object.typeDescription). filename: \(object.filename)]")
             
             if touchDirectory {
-                let directoryURL = self.directoryURL(for: T.self)
-                self.logger.debug("Touching directory. url: \(directoryURL)")
-                try self.fileManager.setAttributes(
+                let directoryURL = directoryURL(for: T.self)
+                logger.debug("Touching directory. url: \(directoryURL)")
+                try fileManager.setAttributes(
                     [.modificationDate: Date.now],
                     ofItemAtPath: directoryURL.path
                 )
             }
         } catch {
-            self.logger.error("Failed to save. object: \(object.typeDescription) filename: \(object.filename)")
+            logger.error("Failed to save. object: \(object.typeDescription) filename: \(object.filename)")
             throw error
         }
     }
@@ -139,14 +139,14 @@ public struct PapyrusStore: Sendable {
             
             for (index, object) in objects.enumerated() {
                 group.addTask {
-                    let url = self.fileURL(for: object.typeDescription, filename: object.filename)
-                    let fileAlreadyExists = self.fileManager.fileExists(atPath: url.path)
-                    try self.save(object, touchDirectory: false)
+                    let url = fileURL(for: object.typeDescription, filename: object.filename)
+                    let fileAlreadyExists = fileManager.fileExists(atPath: url.path)
+                    try save(object, touchDirectory: false)
                     
                     if !fileAlreadyExists {
                         // Because the aren't guaranteed to happen in order
                         // we need to manually set the created at timstamp.
-                        try self.setCreatedAt(
+                        try setCreatedAt(
                             timestamp.addingTimeInterval(TimeInterval(index) / 100000.0),
                             for: url
                         )
@@ -156,9 +156,9 @@ public struct PapyrusStore: Sendable {
             
             try await group.waitForAll()
             
-            let directoryURL = self.directoryURL(for: T.self)
-            self.logger.debug("Touching directory. url: \(directoryURL)")
-            try self.fileManager.setAttributes(
+            let directoryURL = directoryURL(for: T.self)
+            logger.debug("Touching directory. url: \(directoryURL)")
+            try fileManager.setAttributes(
                 [.modificationDate: Date.now],
                 ofItemAtPath: directoryURL.path
             )
@@ -174,7 +174,7 @@ public struct PapyrusStore: Sendable {
     public func object<T: Papyrus, ID: LosslessStringConvertible>(id: ID) -> ObjectQuery<T> {
         ObjectQuery(
             id: id,
-            directoryURL: self.directoryURL(for: T.self)
+            directoryURL: directoryURL(for: T.self)
         )
     }
     
@@ -187,7 +187,7 @@ public struct PapyrusStore: Sendable {
     public func object<T: Papyrus, ID: LosslessStringConvertible>(id: ID, of type: T.Type) -> ObjectQuery<T> {
         ObjectQuery(
             id: id,
-            directoryURL: self.directoryURL(for: T.self)
+            directoryURL: directoryURL(for: T.self)
         )
     }
     
@@ -197,7 +197,7 @@ public struct PapyrusStore: Sendable {
     /// - Returns: A `AnyPublisher<[T], Error>` instance.
     public func objects<T: Papyrus>(type: T.Type) -> CollectionQuery<T> {
         CollectionQuery(
-            directoryURL: self.directoryURL(for: T.self)
+            directoryURL: directoryURL(for: T.self)
         )
     }
     
@@ -211,13 +211,13 @@ public struct PapyrusStore: Sendable {
         id: T.ID,
         of type: T.Type
     ) throws {
-        try self.delete(id: id, of: type, touchDirectory: true)
+        try delete(id: id, of: type, touchDirectory: true)
     }
 
     /// Deletes an object from the store.
     /// - Parameter object: The object to delete.
     public func delete<T: Papyrus>(_ object: T) throws {
-        try self.delete(id: object.id, of: T.self, touchDirectory: true)
+        try delete(id: object.id, of: T.self, touchDirectory: true)
     }
         
     /// Deletes an array of objects.
@@ -228,15 +228,15 @@ public struct PapyrusStore: Sendable {
         try await withThrowingTaskGroup(of: Void.self) { group in
             for object in objects {
                 group.addTask { [id = object.id] in
-                    try self.delete(id: id, of: T.self, touchDirectory: false)
+                    try delete(id: id, of: T.self, touchDirectory: false)
                 }
             }
             
             try await group.waitForAll()
             
-            let directoryURL = self.directoryURL(for: T.self)
-            self.logger.debug("Touching directory. url: \(directoryURL)")
-            try self.fileManager.setAttributes(
+            let directoryURL = directoryURL(for: T.self)
+            logger.debug("Touching directory. url: \(directoryURL)")
+            try fileManager.setAttributes(
                 [.modificationDate: Date.now],
                 ofItemAtPath: directoryURL.path
             )
@@ -244,7 +244,7 @@ public struct PapyrusStore: Sendable {
     }
     
     public func deleteAll<T: Papyrus>(_ type: T.Type) throws {
-        try self.fileManager.removeItem(at: self.directoryURL(for: type))
+        try fileManager.removeItem(at: directoryURL(for: type))
     }
     
     private func delete<T: Papyrus, ID>(
@@ -255,11 +255,11 @@ public struct PapyrusStore: Sendable {
         let objectType = String(describing: type)
         
         do {
-            let url = self.fileURL(for: objectType, id: id)
-            try self.fileManager.removeItem(at: url)
-            self.logger.debug("Deleted object \(objectType). id: \(id)")
+            let url = fileURL(for: objectType, id: id)
+            try fileManager.removeItem(at: url)
+            logger.debug("Deleted object \(objectType). id: \(id)")
         } catch {
-            self.logger.error(
+            logger.error(
                 "Failed to delete. object: \(objectType) id: \(id), url: \(url)"
             )
             throw error
@@ -286,10 +286,10 @@ public struct PapyrusStore: Sendable {
         
         try await withThrowingTaskGroup(of: Void.self, body: { group in
             group.addTask {
-                try await self.delete(objects: objectsToDelete)
+                try await delete(objects: objectsToDelete)
             }
             group.addTask {
-                try await self.save(objects: objects)
+                try await save(objects: objects)
             }
             
             for try await _ in group {} // So we can throw errors
@@ -318,10 +318,10 @@ public struct PapyrusStore: Sendable {
         
         try await withThrowingTaskGroup(of: Void.self) { group in
             group.addTask {
-                try await self.delete(objects: objectsToDelete)
+                try await delete(objects: objectsToDelete)
             }
             group.addTask {
-                try await self.save(objects: objects)
+                try await save(objects: objects)
             }
             
             try await group.waitForAll()
diff --git a/Sources/Papyrus/Queries/CollectionQuery.swift b/Sources/Papyrus/Queries/CollectionQuery.swift
index 395e63f..5d91298 100644
--- a/Sources/Papyrus/Queries/CollectionQuery.swift
+++ b/Sources/Papyrus/Queries/CollectionQuery.swift
@@ -3,7 +3,7 @@ import Foundation
 import os
 
 /// `PapyrusStore.CollectionQuery<T>` is a mechanism for querying `Papyrus` objects.
-public struct CollectionQuery<T> where T: Papyrus {
+public struct CollectionQuery<T>: Sendable where T: Papyrus {
     public typealias OnFilter = @Sendable (T) -> Bool
     public typealias OnSort = @Sendable (T, T) -> Bool
     
@@ -33,7 +33,7 @@ public struct CollectionQuery<T> where T: Papyrus {
     /// set, they will be applied to the results.
     /// - Returns: The results of the query.
     public func execute() -> [T] {
-        self.fetchObjects()
+        fetchObjects()
     }
     
     /// Apply a filter to the query.
@@ -62,9 +62,9 @@ public struct CollectionQuery<T> where T: Papyrus {
     /// - Returns: A `AsyncThrowingStream` instance.
     public func observe() -> AsyncThrowingStream<[T], Error> where T: Sendable {
         do {
-            let observer = try DirectoryObserver(url: self.directoryURL)
+            let observer = try DirectoryObserver(url: directoryURL)
             return observer.observe()
-                .map { _ in self.fetchObjects() }
+                .map { _ in fetchObjects() }
                 .eraseToThrowingStream()
         } catch {
             return Fail(error: error)
@@ -75,46 +75,51 @@ public struct CollectionQuery<T> where T: Papyrus {
     private func fetchObjects() -> [T] {
         do {
             let fileManager = FileManager.default
-            let filenames = try fileManager.contentsOfDirectory(atPath: self.directoryURL.path)
+            let filenames = try fileManager.contentsOfDirectory(atPath: directoryURL.path)
             return filenames.reduce(into: [(Date, T)]()) { result, filename in
+                let url = directoryURL.appendingPathComponent(filename)
                 do {
-                    let url = self.directoryURL.appendingPathComponent(filename)
                     let data = try Data(contentsOf: url)
-                    let model = try self.decoder.decode(T.self, from: data)
+                    let model = try decoder.decode(T.self, from: data)
                     let creationDate = try fileManager.attributesOfItem(
                         atPath: url.path
                     )[.creationDate] as? Date ?? .now
                     result.append((creationDate, model))
                 } catch {
-                    self.logger.error("Failed to read cached data. error: \(error)")
+                    logger.error("Failed to read cached data. error: \(error)")
+                    do {
+                        // Delete cached data
+                        logger.debug("Deleting old cached data. url: \(url)")
+                        try fileManager.removeItem(at: url)
+                    } catch {
+                        logger.error("Failed deleting old cached data. url: \(url) error: \(error)")
+                    }
                 }
             }
             .sorted { $0.0 < $1.0 }
             .map(\.1)
-            .filter(self.filter)
-            .sorted(by: self.sort)
+            .filter(filter)
+            .sorted(by: sort)
         } catch CocoaError.fileReadNoSuchFile {
-            self.logger.info("Failed to read contents of directory. url: \(self.directoryURL)")
+            logger.info("Failed to read contents of directory. url: \(directoryURL)")
             return []
         } catch {
-            self.logger.fault("Unknown error occured. error: \(error)")
+            logger.fault("Unknown error occured. error: \(error)")
             return []
         }
     }
 }
 
-extension CollectionQuery: Sendable {}
-
 // MARK: Sequence
 
 extension Sequence {
     fileprivate func filter(_ isIncluded: ((Element) -> Bool)?) -> [Element] {
         guard let isIncluded = isIncluded else { return Array(self) }
-        return self.filter { isIncluded($0) }
+        return filter { isIncluded($0) }
     }
     
     fileprivate func sorted(by areInIncreasingOrder: ((Element, Element) -> Bool)?) -> [Element] {
         guard let areInIncreasingOrder = areInIncreasingOrder else { return Array(self) }
-        return self.sorted { areInIncreasingOrder($0, $1) }
+        return sorted { areInIncreasingOrder($0, $1) }
     }
 }
diff --git a/Sources/Papyrus/Queries/ObjectQuery.swift b/Sources/Papyrus/Queries/ObjectQuery.swift
index c0a2177..148669a 100644
--- a/Sources/Papyrus/Queries/ObjectQuery.swift
+++ b/Sources/Papyrus/Queries/ObjectQuery.swift
@@ -3,7 +3,7 @@ import Foundation
 import os
 
 /// `ObjectQuery<T>` is a mechanism for querying a single `Papyrus` object.
-public struct ObjectQuery<T: Papyrus> {
+public struct ObjectQuery<T: Papyrus>: Sendable {
     private let decoder: JSONDecoder = .init()
     private let directoryURL: URL
     private let filename: String
@@ -25,7 +25,7 @@ public struct ObjectQuery<T: Papyrus> {
     /// Executes the query.
     /// - Returns: The result of the query.
     public func execute() -> T? {
-        switch self.fetchObject() {
+        switch fetchObject() {
         case .success(let object):
             return object
         case .failure:
@@ -37,7 +37,7 @@ public struct ObjectQuery<T: Papyrus> {
     /// - Returns: A `AsyncThrowingStream` instance.
     public func observe() -> AsyncThrowingStream<ObjectChange<T>, Error> where T: Sendable {
         do {
-            let observer = try DirectoryObserver(url: self.directoryURL)
+            let observer = try DirectoryObserver(url: directoryURL)
             let object = fetchObject()
             let observerSequence = observer.observe()
                 .map { fetchObject() }
@@ -68,9 +68,9 @@ public struct ObjectQuery<T: Papyrus> {
     
     private func fetchObject() -> Result<T, Error> {
         let fileManager = FileManager.default
-        let fileURL = self.directoryURL.appendingPathComponent(self.filename)
+        let fileURL = directoryURL.appendingPathComponent(filename)
         guard fileManager.fileExists(atPath: fileURL.path) else {
-            self.logger.info("Cached data not found. url: \(fileURL)")
+            logger.info("Cached data not found. url: \(fileURL)")
             return .failure(NotFoundError())
         }
         
@@ -79,13 +79,13 @@ public struct ObjectQuery<T: Papyrus> {
             return .success(try decoder.decode(T.self, from: data))
         } catch {
             // Cached data is using an old schema.
-            self.logger.error("Failed to parse cached data. url: \(fileURL)")
+            logger.error("Failed to parse cached data. url: \(fileURL)")
             do {
                 // Delete cached data
-                self.logger.debug("Deleting old cached data. url: \(fileURL)")
+                logger.debug("Deleting old cached data. url: \(fileURL)")
                 try fileManager.removeItem(at: fileURL)
             } catch {
-                self.logger.error("Failed deleting old cached data. url: \(fileURL) error: \(error)")
+                logger.error("Failed deleting old cached data. url: \(fileURL) error: \(error)")
                 return .failure(error)
             }
             return .failure(InvalidSchemaError(details: error))
@@ -93,8 +93,6 @@ public struct ObjectQuery<T: Papyrus> {
     }
 }
 
-extension ObjectQuery: Sendable {}
-
 // MARK: Errors
 
 extension ObjectQuery {
@@ -151,4 +149,5 @@ extension AsyncPairSequence {
     }
 }
 
-extension AsyncPairSequence.Iterator: Sendable where Base.AsyncIterator: Sendable, Element: Sendable {}
+extension AsyncPairSequence.Iterator: Sendable
+where Base.AsyncIterator: Sendable, Element: Sendable {}

From f7cca2580b6a347ef3ed7136b61934d9d1ba0d60 Mon Sep 17 00:00:00 2001
From: Red <me@red.to>
Date: Wed, 23 Apr 2025 12:52:52 +0100
Subject: [PATCH 06/12] remove trailing , for older Swift version

---
 Package.swift | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Package.swift b/Package.swift
index c30f5a0..74886c4 100644
--- a/Package.swift
+++ b/Package.swift
@@ -21,17 +21,17 @@ let package = Package(
             name: "Papyrus",
             dependencies: [
                 .product(name: "AsyncAlgorithms", package: "swift-async-algorithms"),
-            ],
+            ]
         ),
         .testTarget(
             name: "Unit",
             dependencies: ["Papyrus"],
-            exclude: ["Supporting Files/Unit.xctestplan"],
+            exclude: ["Supporting Files/Unit.xctestplan"]
         ),
         .testTarget(
             name: "Performance",
             dependencies: ["Papyrus"],
             exclude: ["Supporting Files/Performance.xctestplan"]
-        ),
-    ],
+        )
+    ]
 )

From 5cc4cc8e002ef726e3ec342f1e9acab4ae63506c Mon Sep 17 00:00:00 2001
From: Red <me@red.to>
Date: Wed, 23 Apr 2025 13:58:57 +0100
Subject: [PATCH 07/12] Remove a couple more

---
 Package.swift | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Package.swift b/Package.swift
index 74886c4..98290a8 100644
--- a/Package.swift
+++ b/Package.swift
@@ -13,14 +13,15 @@ let package = Package(
     products: [
         .library(
             name: "Papyrus",
-            targets: ["Papyrus"]),
+            targets: ["Papyrus"]
+        )
     ],
     dependencies: [.package(url: "https://github.com/apple/swift-async-algorithms", from: "1.0.0")],
     targets: [
         .target(
             name: "Papyrus",
             dependencies: [
-                .product(name: "AsyncAlgorithms", package: "swift-async-algorithms"),
+                .product(name: "AsyncAlgorithms", package: "swift-async-algorithms")
             ]
         ),
         .testTarget(

From 7757f5ba25b97856336253b82b7615fdcf23f38a Mon Sep 17 00:00:00 2001
From: Red <me@red.to>
Date: Mon, 5 Jan 2026 10:33:00 +0000
Subject: [PATCH 08/12] style(CollectionQuery): improve code formatting by
 removing extra whitespace

- Removed unnecessary blank lines and trailing whitespace throughout the file
- Improved code readability while maintaining functionality
---
 Sources/Papyrus/Queries/CollectionQuery.swift | 20 +++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/Sources/Papyrus/Queries/CollectionQuery.swift b/Sources/Papyrus/Queries/CollectionQuery.swift
index 5d91298..80a7e08 100644
--- a/Sources/Papyrus/Queries/CollectionQuery.swift
+++ b/Sources/Papyrus/Queries/CollectionQuery.swift
@@ -6,16 +6,16 @@ import os
 public struct CollectionQuery<T>: Sendable where T: Papyrus {
     public typealias OnFilter = @Sendable (T) -> Bool
     public typealias OnSort = @Sendable (T, T) -> Bool
-    
+
     // Private
     private let decoder: JSONDecoder = .init()
     private let directoryURL: URL
     private let filter: OnFilter?
     private let logger: Logger
     private let sort: OnSort?
-    
+
     // MARK: Initialization
-    
+
     init(
         directoryURL: URL,
         filter: OnFilter? = nil,
@@ -26,16 +26,16 @@ public struct CollectionQuery<T>: Sendable where T: Papyrus {
         self.logger = Logger(subsystem: "com.reddavis.PapyrusStore", category: "CollectionQuery")
         self.sort = sort
     }
-    
+
     // MARK: API
-     
+
     /// Executes the query. If filter or sort parameters are
     /// set, they will be applied to the results.
     /// - Returns: The results of the query.
     public func execute() -> [T] {
         fetchObjects()
     }
-    
+
     /// Apply a filter to the query.
     /// - Parameter onFilter: The filter to be applied.
     /// - Returns: The query item.
@@ -46,7 +46,7 @@ public struct CollectionQuery<T>: Sendable where T: Papyrus {
             sort: sort
         )
     }
-    
+
     /// Apply a sort to the query.
     /// - Parameter onSort: The sort to be applied.
     /// - Returns: The query item.
@@ -57,7 +57,7 @@ public struct CollectionQuery<T>: Sendable where T: Papyrus {
             sort: onSort
         )
     }
-    
+
     /// Observe changes to the query.
     /// - Returns: A `AsyncThrowingStream` instance.
     public func observe() -> AsyncThrowingStream<[T], Error> where T: Sendable {
@@ -71,7 +71,7 @@ public struct CollectionQuery<T>: Sendable where T: Papyrus {
                 .eraseToThrowingStream()
         }
     }
-    
+
     private func fetchObjects() -> [T] {
         do {
             let fileManager = FileManager.default
@@ -117,7 +117,7 @@ extension Sequence {
         guard let isIncluded = isIncluded else { return Array(self) }
         return filter { isIncluded($0) }
     }
-    
+
     fileprivate func sorted(by areInIncreasingOrder: ((Element, Element) -> Bool)?) -> [Element] {
         guard let areInIncreasingOrder = areInIncreasingOrder else { return Array(self) }
         return sorted { areInIncreasingOrder($0, $1) }

From 4e2b696587c53418542a057d589216143d667b65 Mon Sep 17 00:00:00 2001
From: Red <me@red.to>
Date: Mon, 5 Jan 2026 10:33:12 +0000
Subject: [PATCH 09/12] refactor(structure): improve AsyncPairSequence
 organization

- Made AsyncPairSequence and its Iterator fileprivate
- Moved AsyncSequence extension to the bottom of the file
- Grouped related components with appropriate MARK comments
- Removed unnecessary whitespace throughout the file
---
 Sources/Papyrus/Queries/ObjectQuery.swift | 43 ++++++++++++-----------
 1 file changed, 22 insertions(+), 21 deletions(-)

diff --git a/Sources/Papyrus/Queries/ObjectQuery.swift b/Sources/Papyrus/Queries/ObjectQuery.swift
index 148669a..71e503f 100644
--- a/Sources/Papyrus/Queries/ObjectQuery.swift
+++ b/Sources/Papyrus/Queries/ObjectQuery.swift
@@ -8,9 +8,9 @@ public struct ObjectQuery<T: Papyrus>: Sendable {
     private let directoryURL: URL
     private let filename: String
     private let logger: Logger
-    
+
     // MARK: Initialization
-    
+
     init<ID: LosslessStringConvertible>(
         id: ID,
         directoryURL: URL
@@ -19,9 +19,9 @@ public struct ObjectQuery<T: Papyrus>: Sendable {
         self.directoryURL = directoryURL
         self.logger = Logger(subsystem: "com.reddavis.PapyrusStore", category: "ObjectQuery")
     }
-    
+
     // MARK: API
-    
+
     /// Executes the query.
     /// - Returns: The result of the query.
     public func execute() -> T? {
@@ -32,7 +32,7 @@ public struct ObjectQuery<T: Papyrus>: Sendable {
             return nil
         }
     }
-        
+
     /// Observe changes to the query via an async stream.
     /// - Returns: A `AsyncThrowingStream` instance.
     public func observe() -> AsyncThrowingStream<ObjectChange<T>, Error> where T: Sendable {
@@ -41,13 +41,13 @@ public struct ObjectQuery<T: Papyrus>: Sendable {
             let object = fetchObject()
             let observerSequence = observer.observe()
                 .map { fetchObject() }
-            
+
             return chain(Just(object), observerSequence)
                 .pair()
                 .compactMap { tuple in
                     let previousResult = tuple.0
                     let result = tuple.1
-                    
+
                     switch (previousResult, result) {
                     case (.success(let previousModel), .success(let model)) where previousModel != model:
                         return .changed(model)
@@ -65,7 +65,7 @@ public struct ObjectQuery<T: Papyrus>: Sendable {
                 .eraseToThrowingStream()
         }
     }
-    
+
     private func fetchObject() -> Result<T, Error> {
         let fileManager = FileManager.default
         let fileURL = directoryURL.appendingPathComponent(filename)
@@ -73,7 +73,7 @@ public struct ObjectQuery<T: Papyrus>: Sendable {
             logger.info("Cached data not found. url: \(fileURL)")
             return .failure(NotFoundError())
         }
-        
+
         do {
             let data = try Data(contentsOf: fileURL)
             return .success(try decoder.decode(T.self, from: data))
@@ -102,14 +102,9 @@ extension ObjectQuery {
     }
 }
 
+// MARK: AsyncPairSequence
 
-extension AsyncSequence {
-    func pair() -> AsyncPairSequence<Self> {
-        AsyncPairSequence(base: self)
-    }
-}
-
-struct AsyncPairSequence<Base: AsyncSequence>: AsyncSequence {
+fileprivate struct AsyncPairSequence<Base: AsyncSequence>: AsyncSequence {
     typealias AsyncIterator = Iterator
     typealias Element = (Base.Element, Base.Element)
     var base: Base
@@ -121,10 +116,10 @@ struct AsyncPairSequence<Base: AsyncSequence>: AsyncSequence {
 
 extension AsyncPairSequence: Sendable where Base: Sendable, Element: Sendable {}
 
-// MARK: Iterator
+// MARK: AsyncPairSequence Iterator
 
 extension AsyncPairSequence {
-    struct Iterator: AsyncIteratorProtocol {
+    fileprivate struct Iterator: AsyncIteratorProtocol {
         var base: Base.AsyncIterator
         var lastValue: Base.Element?
 
@@ -132,17 +127,17 @@ extension AsyncPairSequence {
             guard let nextValue = try await base.next() else {
                 return nil
             }
-            
+
             guard let lastValue else {
                 lastValue = nextValue
                 guard let nextNextValue = try await base.next() else {
                     return nil
                 }
-                
+
                 lastValue = nextNextValue
                 return (nextValue, nextNextValue)
             }
-            
+
             defer { self.lastValue = nextValue }
             return (lastValue, nextValue)
         }
@@ -151,3 +146,9 @@ extension AsyncPairSequence {
 
 extension AsyncPairSequence.Iterator: Sendable
 where Base.AsyncIterator: Sendable, Element: Sendable {}
+
+extension AsyncSequence {
+    fileprivate func pair() -> AsyncPairSequence<Self> {
+        AsyncPairSequence(base: self)
+    }
+}

From 6d410890e8dd177eafd81e6b4de83824208c9ce3 Mon Sep 17 00:00:00 2001
From: Red <me@red.to>
Date: Mon, 5 Jan 2026 10:33:23 +0000
Subject: [PATCH 10/12] chore(deps): update swift-async-algorithms to 1.1.1

- Upgraded swift-async-algorithms package from 1.0.0 to 1.1.1
- Updated swift-collections dependency from 1.1.1 to 1.3.0
- Package.resolved file updated to version 3 format with originHash
---
 Package.resolved | 11 ++++++-----
 Package.swift    |  2 +-
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/Package.resolved b/Package.resolved
index 7142500..0b389e9 100644
--- a/Package.resolved
+++ b/Package.resolved
@@ -1,12 +1,13 @@
 {
+  "originHash" : "56d20ae0e9b26ba8fd8e419a8c54d6482d21800a8ce4cf2b6340fe42c6e3185e",
   "pins" : [
     {
       "identity" : "swift-async-algorithms",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-async-algorithms",
       "state" : {
-        "revision" : "da4e36f86544cdf733a40d59b3a2267e3a7bbf36",
-        "version" : "1.0.0"
+        "revision" : "6c050d5ef8e1aa6342528460db614e9770d7f804",
+        "version" : "1.1.1"
       }
     },
     {
@@ -14,10 +15,10 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-collections.git",
       "state" : {
-        "revision" : "ee97538f5b81ae89698fd95938896dec5217b148",
-        "version" : "1.1.1"
+        "revision" : "7b847a3b7008b2dc2f47ca3110d8c782fb2e5c7e",
+        "version" : "1.3.0"
       }
     }
   ],
-  "version" : 2
+  "version" : 3
 }
diff --git a/Package.swift b/Package.swift
index 98290a8..4724d17 100644
--- a/Package.swift
+++ b/Package.swift
@@ -16,7 +16,7 @@ let package = Package(
             targets: ["Papyrus"]
         )
     ],
-    dependencies: [.package(url: "https://github.com/apple/swift-async-algorithms", from: "1.0.0")],
+    dependencies: [.package(url: "https://github.com/apple/swift-async-algorithms", from: "1.1.1")],
     targets: [
         .target(
             name: "Papyrus",

From 950c88df8708e36a3202cab623beb0bd70151d22 Mon Sep 17 00:00:00 2001
From: Red <me@red.to>
Date: Mon, 5 Jan 2026 10:38:12 +0000
Subject: [PATCH 11/12] ci: update GitHub Actions workflow configuration

- Changed macOS runner from macOS-13 to macOS-26
---
 .github/workflows/ci.yml | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6120009..14fe285 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,21 +1,20 @@
 name: "CI"
 
-on: 
+on:
   push:
-    branches: 
+    branches:
       - main
   pull_request:
-    branches: 
+    branches:
       - '*'
 
 jobs:
   test:
     name: Unit Tests
-    runs-on: macOS-13
-    env: 
+    runs-on: macOS-26
+    env:
       DEVELOPER_DIR: /Applications/Xcode_15.0.app/Contents/Developer
     steps:
       - uses: actions/checkout@v2
       - name: Run Tests
         run: swift test
-  
\ No newline at end of file

From 0c79ec938334ebcaf485118e0c8fe2d8378a81a8 Mon Sep 17 00:00:00 2001
From: Red <me@red.to>
Date: Mon, 5 Jan 2026 10:41:25 +0000
Subject: [PATCH 12/12] chore(ci): update Xcode version in GitHub workflow

- Updated DEVELOPER_DIR path from Xcode 15.0 to Xcode 26.2 for macOS CI runner
---
 .github/workflows/ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 14fe285..8e2b648 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,7 +13,7 @@ jobs:
     name: Unit Tests
     runs-on: macOS-26
     env:
-      DEVELOPER_DIR: /Applications/Xcode_15.0.app/Contents/Developer
+      DEVELOPER_DIR: /Applications/Xcode_26.2.app/Contents/Developer
     steps:
       - uses: actions/checkout@v2
       - name: Run Tests