From 71d5c1f2afc6a2c809efb42eba731948d2ac8747 Mon Sep 17 00:00:00 2001
From: Sean <sean@snowfort.software>
Date: Fri, 27 Sep 2024 17:02:22 -0400
Subject: [PATCH 1/5] Modified `Gen` to be `Sendable`. Requires its `Value` to
 also be `Sendable`

---
 Package.swift                 |   8 +-
 Sources/Gen/Gen.swift         | 144 +++++++++++++++++++++-------------
 Sources/Gen/Zip.swift         |  22 ++++++
 Tests/GenTests/GenTests.swift |   4 +-
 4 files changed, 121 insertions(+), 57 deletions(-)

diff --git a/Package.swift b/Package.swift
index 55aa546..c727a75 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.0
+// swift-tools-version:5.9
 import Foundation
 import PackageDescription
 
@@ -8,7 +8,11 @@ let package = Package(
     .library(name: "Gen", targets: ["Gen"])
   ],
   targets: [
-    .target(name: "Gen", dependencies: []),
+    .target(
+      name: "Gen",
+      dependencies: [],
+      swiftSettings: [.enableExperimentalFeature("StrictConcurrency")]
+    ),
     .testTarget(name: "GenTests", dependencies: ["Gen"]),
   ]
 )
diff --git a/Sources/Gen/Gen.swift b/Sources/Gen/Gen.swift
index 04c072e..b46fd20 100644
--- a/Sources/Gen/Gen.swift
+++ b/Sources/Gen/Gen.swift
@@ -1,10 +1,10 @@
 /// A composable, transformable context for generating random values.
-public struct Gen<Value> {
+public struct Gen<Value: Sendable>: Sendable {
   @usableFromInline
-  internal var _run: (inout AnyRandomNumberGenerator) -> Value
+  internal var _run: @Sendable (inout AnyRandomNumberGenerator) -> Value
 
   @inlinable
-  public init(run: @escaping (inout AnyRandomNumberGenerator) -> Value) {
+  public init(run: @escaping @Sendable (inout AnyRandomNumberGenerator) -> Value) {
     self._run = run
   }
 
@@ -13,6 +13,7 @@ public struct Gen<Value> {
   /// - Parameter rng: A random number generator.
   /// - Returns: A random value.
   @inlinable
+  @Sendable
   public func run<G: RandomNumberGenerator>(using rng: inout G) -> Value {
     if var arng = rng as? AnyRandomNumberGenerator {
       defer { rng = arng as! G }
@@ -27,6 +28,7 @@ public struct Gen<Value> {
   ///
   /// - Returns: A random value.
   @inlinable
+  @Sendable
   public func run() -> Value {
     var rng = SystemRandomNumberGenerator()
     return self.run(using: &rng)
@@ -39,6 +41,7 @@ extension Gen {
   /// - Parameter value: A constant value.
   /// - Returns: A generator of a constant value.
   @inlinable
+  @Sendable
   public static func always(_ value: Value) -> Gen {
     return Gen { _ in value }
   }
@@ -48,31 +51,24 @@ extension Gen {
   /// - Parameter transform: A function that transforms `Value`s into `NewValue`s.
   /// - Returns: A generator of `NewValue`s.
   @inlinable
-  public func map<NewValue>(_ transform: @escaping (Value) -> NewValue) -> Gen<NewValue> {
+  @Sendable
+  public func map<NewValue>(
+    _ transform: @escaping @Sendable (Value) -> NewValue
+  ) -> Gen<NewValue> {
     return Gen<NewValue> { rng in transform(self._run(&rng)) }
   }
 }
 
-/// Combines two generators into a single one.
-///
-/// - Parameters:
-///   - a: A generator of `A`s.
-///   - b: A generator of `B`s.
-/// - Returns: A generator of `(A, B)` pairs.
-@inlinable
-public func zip<A, B>(_ a: Gen<A>, _ b: Gen<B>) -> Gen<(A, B)> {
-  return Gen<(A, B)> { rng in
-    (a._run(&rng), b._run(&rng))
-  }
-}
-
 extension Gen {
   /// Transforms a generator of `Value`s into a generator of `NewValue`s by transforming a value into a generator of `NewValue`s.
   ///
   /// - Parameter transform: A function that transforms `Value`s into a generator of `NewValue`s.
   /// - Returns: A generator of `NewValue`s.
   @inlinable
-  public func flatMap<NewValue>(_ transform: @escaping (Value) -> Gen<NewValue>) -> Gen<NewValue> {
+  @Sendable
+  public func flatMap<NewValue>(
+    _ transform: @escaping @Sendable (Value) -> Gen<NewValue>
+  ) -> Gen<NewValue> {
     return Gen<NewValue> { rng in
       transform(self._run(&rng))._run(&rng)
     }
@@ -83,7 +79,10 @@ extension Gen {
   /// - Parameter transform: A closure that accepts an element of this sequence as its argument and returns an optional value.
   /// - Returns: A generator of the non-nil results of calling the given transformation with a value of the generator.
   @inlinable
-  public func compactMap<NewValue>(_ transform: @escaping (Value) -> NewValue?) -> Gen<NewValue> {
+  @Sendable
+  public func compactMap<NewValue>(
+    _ transform: @escaping @Sendable (Value) -> NewValue?
+  ) -> Gen<NewValue> {
     return Gen<NewValue> { rng in
       while true {
         if let value = transform(self._run(&rng)) {
@@ -98,18 +97,21 @@ extension Gen {
   /// - Parameter predicate: A predicate.
   /// - Returns: A generator of values that match the predicate.
   @inlinable
-  public func filter(_ predicate: @escaping (Value) -> Bool) -> Gen<Value> {
+  @Sendable
+  public func filter(_ predicate: @escaping @Sendable (Value) -> Bool) -> Gen<Value> {
     return self.compactMap { predicate($0) ? $0 : nil }
   }
 
   /// Uses a weighted distribution to randomly select one of the generators in the list.
   @inlinable
+  @Sendable
   public static func frequency(_ distribution: (Int, Gen)...) -> Gen {
     return frequency(distribution)
   }
 
   /// Uses a weighted distribution to randomly select one of the generators in the list.
   @inlinable
+  @Sendable
   public static func frequency(_ distribution: [(Int, Gen)]) -> Gen {
     // TODO: Add `!distribution.isEmpty` precondition?
     let generators = distribution.flatMap { Array(repeating: $1, count: $0) }
@@ -121,167 +123,182 @@ extension Gen {
   }
 }
 
-extension Gen where Value: FixedWidthInteger {
+extension Gen where Value: FixedWidthInteger & Sendable {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func int(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in Value.random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value: BinaryFloatingPoint, Value.RawSignificand: FixedWidthInteger {
+extension Gen where Value: BinaryFloatingPoint & Sendable, Value.RawSignificand: FixedWidthInteger {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func float(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in Value.random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value == Int {
+extension Gen<Int> {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func int(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value == Int8 {
+extension Gen<Int8> {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func int8(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value == Int16 {
+extension Gen<Int16> {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func int16(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value == Int32 {
+extension Gen<Int32> {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func int32(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value == Int64 {
+extension Gen<Int64> {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func int64(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value == UInt {
+extension Gen<UInt> {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func uint(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value == UInt8 {
+extension Gen<UInt8> {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func uint8(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value == UInt16 {
+extension Gen<UInt16> {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func uint16(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value == UInt32 {
+extension Gen<UInt32> {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func uint32(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value == UInt64 {
+extension Gen<UInt64> {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func uint64(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value == Double {
+extension Gen<Double> {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func double(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value == Float {
+extension Gen<Float> {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
+  @Sendable
   public static func float32(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
 }
 
 #if !(os(Windows) || os(Android)) && (arch(i386) || arch(x86_64))
-  extension Gen where Value == Float80 {
+  extension Gen<Float80> {
     /// Returns a generator of random values within the specified range.
     ///
     /// - Parameter range: The range in which to create a random value. `range` must be finite.
     /// - Returns: A generator of random values within the bounds of range.
     @inlinable
+    @Sendable
     public static func float80(in range: ClosedRange<Value>) -> Gen {
       return Gen { rng in .random(in: range, using: &rng) }
     }
@@ -291,19 +308,20 @@ extension Gen where Value == Float {
 #if canImport(CoreGraphics)
   import CoreGraphics
 
-  extension Gen where Value == CGFloat {
+  extension Gen<CGFloat> {
     /// Returns a generator of random values within the specified range.
     ///
     /// - Parameter range: The range in which to create a random value. `range` must be finite.
     /// - Returns: A generator of random values within the bounds of range.
     @inlinable
+    @Sendable
     public static func cgFloat(in range: ClosedRange<Value>) -> Gen {
       return Gen { rng in .random(in: range, using: &rng) }
     }
   }
 #endif
 
-extension Gen where Value == Bool {
+extension Gen<Bool> {
   /// A generator of random boolean values.
   public static let bool = Gen { rng in Bool.random(using: &rng) }
 }
@@ -313,7 +331,9 @@ extension Gen {
   ///
   /// - Parameter collection: A collection.
   @inlinable
-  public static func element<C>(of collection: C) -> Gen where C: Collection, Value == C.Element? {
+  @Sendable
+  public static func element<C>(of collection: C) -> Gen
+  where C: Collection & Sendable, Value == C.Element? {
     return Gen { rng in collection.randomElement(using: &rng) }
   }
 
@@ -321,12 +341,14 @@ extension Gen {
   ///
   /// - Parameter collection: A collection.
   @inlinable
-  public static func shuffled<C>(_ collection: C) -> Gen where C: Collection, Value == [C.Element] {
+  @Sendable
+  public static func shuffled<C>(_ collection: C) -> Gen
+  where C: Collection & Sendable, Value == [C.Element] {
     return Gen { rng in collection.shuffled(using: &rng) }
   }
 }
 
-extension Gen where Value: Collection {
+extension Gen where Value: Collection, Value.Element: Sendable {
   /// Produces a generator of random elements of this generator's collection.
   @inlinable
   public var element: Gen<Value.Element?> {
@@ -340,7 +362,7 @@ extension Gen where Value: Collection {
   }
 }
 
-extension Gen where Value: CaseIterable {
+extension Gen where Value: CaseIterable, Value.AllCases: Sendable {
   /// Produces a generator of all case-iterable cases.
   @inlinable
   public static var allCases: Gen<Value> {
@@ -354,6 +376,7 @@ extension Gen {
   /// - Parameter count: The size of the random collection.
   /// - Returns: A generator of collections.
   @inlinable
+  @Sendable
   public func collection<C>(of count: Gen<Int>) -> Gen<C>
   where C: RangeReplaceableCollection, C.Element == Value {
     return count.flatMap { count in
@@ -369,12 +392,13 @@ extension Gen {
       }
     }
   }
-
+  
   /// Produces a new generator of arrays of this generator's values.
   ///
   /// - Parameter count: The size of the random array.
   /// - Returns: A generator of arrays.
   @inlinable
+  @Sendable
   public func array(of count: Gen<Int>) -> Gen<[Value]> {
     return count.flatMap { count in
       guard count > 0 else { return .always([]) }
@@ -388,12 +412,13 @@ extension Gen {
       }
     }
   }
-
+  
   /// Produces a new generator of dictionaries of this generator's pairs.
   ///
   /// - Parameter count: The size of the random dictionary.
   /// - Returns: A generator of dictionaries.
   @inlinable
+  @Sendable
   public func dictionary<K, V>(ofAtMost count: Gen<Int>) -> Gen<[K: V]> where Value == (K, V) {
     return count.flatMap { count in
       guard count > 0 else { return .always([:]) }
@@ -408,12 +433,13 @@ extension Gen {
       }
     }
   }
-
+  
   /// Produces a new generator of sets of this generator's values.
   ///
   /// - Parameter count: The size of the random set.
   /// - Returns: A generator of sets.
   @inlinable
+  @Sendable
   public func set<S>(ofAtMost count: Gen<Int>) -> Gen<S> where S: SetAlgebra, S.Element == Value {
     return count.flatMap { count in
       guard count > 0 else { return .always(S()) }
@@ -426,7 +452,9 @@ extension Gen {
       }
     }
   }
+}
 
+extension Gen {
   /// Produces a new generator of optional values.
   ///
   /// - Returns: A generator of optional values.
@@ -434,7 +462,7 @@ extension Gen {
   public var optional: Gen<Value?> {
     return Gen<Value?>.frequency(
       (1, Gen<Value?>.always(Value?.none)),
-      (3, self.map(Value?.some))  // TODO: Change to use `size` with resizable generators?
+      (3, self.map { Value?.some($0) })  // TODO: Change to use `size` with resizable generators?
     )
   }
 
@@ -442,10 +470,11 @@ extension Gen {
   ///
   /// - Returns: A generator of failable values.
   @inlinable
+  @Sendable
   public func asResult<Failure>(withFailure gen: Gen<Failure>) -> Gen<Result<Value, Failure>> {
     return Gen<Result<Value, Failure>>.frequency(
-      (1, gen.map(Result.failure)),
-      (3, self.map(Result.success))  // TODO: Change to use `size` with resizable generators?
+      (1, gen.map { Result.failure($0) }),
+      (3, self.map { Result.success($0) })  // TODO: Change to use `size` with resizable generators?
     )
   }
 }
@@ -456,6 +485,7 @@ extension Gen where Value: Hashable {
   /// - Parameter count: The size of the random set.
   /// - Returns: A generator of sets.
   @inlinable
+  @Sendable
   public func set(ofAtMost count: Gen<Int>) -> Gen<Set<Value>> {
     return count.flatMap { count in
       guard count > 0 else { return .always([]) }
@@ -470,12 +500,13 @@ extension Gen where Value: Hashable {
   }
 }
 
-extension Gen where Value == UnicodeScalar {
+extension Gen<UnicodeScalar> {
   /// Returns a generator of random unicode scalars within the specified range.
   ///
   /// - Parameter range: The range in which to create a random unicode scalar. `range` must be finite.
   /// - Returns: A generator of random unicode scalars within the bounds of range.
   @inlinable
+  @Sendable
   public static func unicodeScalar(in range: ClosedRange<Value>) -> Gen {
     return Gen<UInt32>
       .int(in: range.lowerBound.value...range.upperBound.value)
@@ -483,19 +514,20 @@ extension Gen where Value == UnicodeScalar {
   }
 }
 
-extension Gen where Value == Character {
+extension Gen<Character> {
   // FIXME: Make safe for characters with multiple scalars.
   /// Returns a generator of random characters within the specified range.
   ///
   /// - Parameter range: The range in which to create a random character. `range` must be finite.
   /// - Returns: A generator of random characters within the bounds of range.
   @inlinable
+  @Sendable
   public static func character(in range: ClosedRange<Value>) -> Gen {
     return Gen<UnicodeScalar>
       .unicodeScalar(
         in: range.lowerBound.unicodeScalars.first!...range.upperBound.unicodeScalars.last!
       )
-      .map(Character.init)
+      .map { Character($0) }
   }
 
   /// A generator of random numeric digits.
@@ -532,18 +564,24 @@ extension Gen where Value == Character {
   /// - Parameter count: The size of the random string.
   /// - Returns: A generator of strings.
   @inlinable
+  @Sendable
   public func string(of count: Gen<Int>) -> Gen<String> {
-    return self.map(String.init).array(of: count).map { $0.joined() }
+    return self
+      .map { String($0) }
+      .array(of: count)
+      .map { $0.joined() }
   }
 }
 
-extension Sequence {
+extension Sequence where Self: Sendable, Element: Sendable {
   /// Transforms each value of an array of generators before rewrapping the array in an array generator.
   ///
   /// - Parameter transform: A transform function to apply to the value of each generator.
   /// - Returns: A generator of arrays.
   @inlinable
-  public func traverse<A, B>(_ transform: @escaping (A) -> B) -> Gen<[B]> where Element == Gen<A> {
+  public func traverse<A, B>(
+    _ transform: @escaping @Sendable (A) -> B
+  ) -> Gen<[B]> where Element == Gen<A> {
     return Gen<[B]> { rng in
       self.map { transform($0.run(using: &rng)) }
     }
diff --git a/Sources/Gen/Zip.swift b/Sources/Gen/Zip.swift
index 9fa3095..24cb696 100644
--- a/Sources/Gen/Zip.swift
+++ b/Sources/Gen/Zip.swift
@@ -1,4 +1,19 @@
+/// Combines two generators into a single one.
+///
+/// - Parameters:
+///   - a: A generator of `A`s.
+///   - b: A generator of `B`s.
+/// - Returns: A generator of `(A, B)` pairs.
 @inlinable
+@Sendable
+public func zip<A, B>(_ a: Gen<A>, _ b: Gen<B>) -> Gen<(A, B)> {
+  return Gen<(A, B)> { rng in
+    (a._run(&rng), b._run(&rng))
+  }
+}
+
+@inlinable
+@Sendable
 public func zip<A, B, C>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -10,6 +25,7 @@ public func zip<A, B, C>(
 }
 
 @inlinable
+@Sendable
 public func zip<A, B, C, D>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -22,6 +38,7 @@ public func zip<A, B, C, D>(
 }
 
 @inlinable
+@Sendable
 public func zip<A, B, C, D, E>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -35,6 +52,7 @@ public func zip<A, B, C, D, E>(
 }
 
 @inlinable
+@Sendable
 public func zip<A, B, C, D, E, F>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -49,6 +67,7 @@ public func zip<A, B, C, D, E, F>(
 }
 
 @inlinable
+@Sendable
 public func zip<A, B, C, D, E, F, G>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -64,6 +83,7 @@ public func zip<A, B, C, D, E, F, G>(
 }
 
 @inlinable
+@Sendable
 public func zip<A, B, C, D, E, F, G, H>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -80,6 +100,7 @@ public func zip<A, B, C, D, E, F, G, H>(
 }
 
 @inlinable
+@Sendable
 public func zip<A, B, C, D, E, F, G, H, I>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -97,6 +118,7 @@ public func zip<A, B, C, D, E, F, G, H, I>(
 }
 
 @inlinable
+@Sendable
 public func zip<A, B, C, D, E, F, G, H, I, J>(
   _ a: Gen<A>,
   _ b: Gen<B>,
diff --git a/Tests/GenTests/GenTests.swift b/Tests/GenTests/GenTests.swift
index 757aa38..c0fe07e 100644
--- a/Tests/GenTests/GenTests.swift
+++ b/Tests/GenTests/GenTests.swift
@@ -5,7 +5,7 @@ final class GenTests: XCTestCase {
   var xoshiro = Xoshiro(seed: 0)
 
   func testMap() {
-    let gen = Gen.bool.map(String.init)
+    let gen = Gen.bool.map { String($0) }
     XCTAssertEqual("false", gen.run(using: &xoshiro))
   }
 
@@ -101,7 +101,7 @@ final class GenTests: XCTestCase {
   }
 
   func testTraverse() {
-    let gen = [Gen.int(in: 1...100), Gen.int(in: 1_000...1_000_000)].traverse(String.init)
+    let gen = [Gen.int(in: 1...100), Gen.int(in: 1_000...1_000_000)].traverse { String($0) }
     XCTAssertEqual(["15", "18473"], gen.run(using: &xoshiro))
   }
 

From 1db3f1f6f40c1c4d805f17488a357f0f54ee3110 Mon Sep 17 00:00:00 2001
From: seanmrich <sean.rich.register@mac.com>
Date: Fri, 27 Sep 2024 17:07:19 -0400
Subject: [PATCH 2/5] Update ci.yml

---
 .github/workflows/ci.yml | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 75ef6bd..7d06236 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,17 +13,22 @@ jobs:
     name: MacOS
     runs-on: macOS-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Run tests
       run: make test-swift
     - name: Run tests
       run: make build-release-swift
 
   ubuntu:
-    name: Ubuntu
+    strategy: 
+      matrix:
+        swift:
+          - '5.9'
+    name: Ubuntu (Swift ${{ matrix.swift }})
     runs-on: ubuntu-latest
+    container: swift:${{ matrix.swift }}
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Run tests
       run: make test-linux
     - name: Build for release

From c0bf72512b80fb3e9adf9a19b9e4fd92e780a65b Mon Sep 17 00:00:00 2001
From: seanmrich <sean.rich.register@mac.com>
Date: Thu, 10 Oct 2024 12:46:19 -0400
Subject: [PATCH 3/5] Minimized use of Sendable to only what's necessary to
 make `Gen` Sendable

---
 Sources/Gen/Gen.swift | 44 ++++---------------------------------------
 Sources/Gen/Zip.swift |  9 ---------
 2 files changed, 4 insertions(+), 49 deletions(-)

diff --git a/Sources/Gen/Gen.swift b/Sources/Gen/Gen.swift
index b46fd20..57b44c8 100644
--- a/Sources/Gen/Gen.swift
+++ b/Sources/Gen/Gen.swift
@@ -13,7 +13,6 @@ public struct Gen<Value: Sendable>: Sendable {
   /// - Parameter rng: A random number generator.
   /// - Returns: A random value.
   @inlinable
-  @Sendable
   public func run<G: RandomNumberGenerator>(using rng: inout G) -> Value {
     if var arng = rng as? AnyRandomNumberGenerator {
       defer { rng = arng as! G }
@@ -28,7 +27,6 @@ public struct Gen<Value: Sendable>: Sendable {
   ///
   /// - Returns: A random value.
   @inlinable
-  @Sendable
   public func run() -> Value {
     var rng = SystemRandomNumberGenerator()
     return self.run(using: &rng)
@@ -41,7 +39,6 @@ extension Gen {
   /// - Parameter value: A constant value.
   /// - Returns: A generator of a constant value.
   @inlinable
-  @Sendable
   public static func always(_ value: Value) -> Gen {
     return Gen { _ in value }
   }
@@ -51,7 +48,6 @@ extension Gen {
   /// - Parameter transform: A function that transforms `Value`s into `NewValue`s.
   /// - Returns: A generator of `NewValue`s.
   @inlinable
-  @Sendable
   public func map<NewValue>(
     _ transform: @escaping @Sendable (Value) -> NewValue
   ) -> Gen<NewValue> {
@@ -65,7 +61,6 @@ extension Gen {
   /// - Parameter transform: A function that transforms `Value`s into a generator of `NewValue`s.
   /// - Returns: A generator of `NewValue`s.
   @inlinable
-  @Sendable
   public func flatMap<NewValue>(
     _ transform: @escaping @Sendable (Value) -> Gen<NewValue>
   ) -> Gen<NewValue> {
@@ -79,7 +74,6 @@ extension Gen {
   /// - Parameter transform: A closure that accepts an element of this sequence as its argument and returns an optional value.
   /// - Returns: A generator of the non-nil results of calling the given transformation with a value of the generator.
   @inlinable
-  @Sendable
   public func compactMap<NewValue>(
     _ transform: @escaping @Sendable (Value) -> NewValue?
   ) -> Gen<NewValue> {
@@ -97,21 +91,18 @@ extension Gen {
   /// - Parameter predicate: A predicate.
   /// - Returns: A generator of values that match the predicate.
   @inlinable
-  @Sendable
   public func filter(_ predicate: @escaping @Sendable (Value) -> Bool) -> Gen<Value> {
     return self.compactMap { predicate($0) ? $0 : nil }
   }
 
   /// Uses a weighted distribution to randomly select one of the generators in the list.
   @inlinable
-  @Sendable
   public static func frequency(_ distribution: (Int, Gen)...) -> Gen {
     return frequency(distribution)
   }
 
   /// Uses a weighted distribution to randomly select one of the generators in the list.
   @inlinable
-  @Sendable
   public static func frequency(_ distribution: [(Int, Gen)]) -> Gen {
     // TODO: Add `!distribution.isEmpty` precondition?
     let generators = distribution.flatMap { Array(repeating: $1, count: $0) }
@@ -123,25 +114,23 @@ extension Gen {
   }
 }
 
-extension Gen where Value: FixedWidthInteger & Sendable {
+extension Gen where Value: FixedWidthInteger {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func int(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in Value.random(in: range, using: &rng) }
   }
 }
 
-extension Gen where Value: BinaryFloatingPoint & Sendable, Value.RawSignificand: FixedWidthInteger {
+extension Gen where Value: BinaryFloatingPoint, Value.RawSignificand: FixedWidthInteger {
   /// Returns a generator of random values within the specified range.
   ///
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func float(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in Value.random(in: range, using: &rng) }
   }
@@ -153,7 +142,6 @@ extension Gen<Int> {
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func int(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
@@ -165,7 +153,6 @@ extension Gen<Int8> {
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func int8(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
@@ -177,7 +164,6 @@ extension Gen<Int16> {
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func int16(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
@@ -189,7 +175,6 @@ extension Gen<Int32> {
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func int32(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
@@ -201,7 +186,6 @@ extension Gen<Int64> {
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func int64(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
@@ -213,7 +197,6 @@ extension Gen<UInt> {
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func uint(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
@@ -225,7 +208,6 @@ extension Gen<UInt8> {
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func uint8(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
@@ -237,7 +219,6 @@ extension Gen<UInt16> {
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func uint16(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
@@ -249,7 +230,6 @@ extension Gen<UInt32> {
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func uint32(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
@@ -261,7 +241,6 @@ extension Gen<UInt64> {
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func uint64(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
@@ -273,7 +252,6 @@ extension Gen<Double> {
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func double(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
@@ -285,7 +263,6 @@ extension Gen<Float> {
   /// - Parameter range: The range in which to create a random value. `range` must be finite.
   /// - Returns: A generator of random values within the bounds of range.
   @inlinable
-  @Sendable
   public static func float32(in range: ClosedRange<Value>) -> Gen {
     return Gen { rng in .random(in: range, using: &rng) }
   }
@@ -298,7 +275,6 @@ extension Gen<Float> {
     /// - Parameter range: The range in which to create a random value. `range` must be finite.
     /// - Returns: A generator of random values within the bounds of range.
     @inlinable
-    @Sendable
     public static func float80(in range: ClosedRange<Value>) -> Gen {
       return Gen { rng in .random(in: range, using: &rng) }
     }
@@ -314,7 +290,6 @@ extension Gen<Float> {
     /// - Parameter range: The range in which to create a random value. `range` must be finite.
     /// - Returns: A generator of random values within the bounds of range.
     @inlinable
-    @Sendable
     public static func cgFloat(in range: ClosedRange<Value>) -> Gen {
       return Gen { rng in .random(in: range, using: &rng) }
     }
@@ -331,7 +306,6 @@ extension Gen {
   ///
   /// - Parameter collection: A collection.
   @inlinable
-  @Sendable
   public static func element<C>(of collection: C) -> Gen
   where C: Collection & Sendable, Value == C.Element? {
     return Gen { rng in collection.randomElement(using: &rng) }
@@ -341,7 +315,6 @@ extension Gen {
   ///
   /// - Parameter collection: A collection.
   @inlinable
-  @Sendable
   public static func shuffled<C>(_ collection: C) -> Gen
   where C: Collection & Sendable, Value == [C.Element] {
     return Gen { rng in collection.shuffled(using: &rng) }
@@ -352,13 +325,13 @@ extension Gen where Value: Collection, Value.Element: Sendable {
   /// Produces a generator of random elements of this generator's collection.
   @inlinable
   public var element: Gen<Value.Element?> {
-    return self.flatMap(Gen<Value.Element?>.element)
+    self.flatMap { Gen<Value.Element?>.element(of: $0) }
   }
 
   /// Produces a generator of shuffled arrays of this generator's collection.
   @inlinable
   public var shuffled: Gen<[Value.Element]> {
-    return self.flatMap(Gen<[Value.Element]>.shuffled)
+    self.flatMap { Gen<[Value.Element]>.shuffled($0) }
   }
 }
 
@@ -376,7 +349,6 @@ extension Gen {
   /// - Parameter count: The size of the random collection.
   /// - Returns: A generator of collections.
   @inlinable
-  @Sendable
   public func collection<C>(of count: Gen<Int>) -> Gen<C>
   where C: RangeReplaceableCollection, C.Element == Value {
     return count.flatMap { count in
@@ -398,7 +370,6 @@ extension Gen {
   /// - Parameter count: The size of the random array.
   /// - Returns: A generator of arrays.
   @inlinable
-  @Sendable
   public func array(of count: Gen<Int>) -> Gen<[Value]> {
     return count.flatMap { count in
       guard count > 0 else { return .always([]) }
@@ -418,7 +389,6 @@ extension Gen {
   /// - Parameter count: The size of the random dictionary.
   /// - Returns: A generator of dictionaries.
   @inlinable
-  @Sendable
   public func dictionary<K, V>(ofAtMost count: Gen<Int>) -> Gen<[K: V]> where Value == (K, V) {
     return count.flatMap { count in
       guard count > 0 else { return .always([:]) }
@@ -439,7 +409,6 @@ extension Gen {
   /// - Parameter count: The size of the random set.
   /// - Returns: A generator of sets.
   @inlinable
-  @Sendable
   public func set<S>(ofAtMost count: Gen<Int>) -> Gen<S> where S: SetAlgebra, S.Element == Value {
     return count.flatMap { count in
       guard count > 0 else { return .always(S()) }
@@ -470,7 +439,6 @@ extension Gen {
   ///
   /// - Returns: A generator of failable values.
   @inlinable
-  @Sendable
   public func asResult<Failure>(withFailure gen: Gen<Failure>) -> Gen<Result<Value, Failure>> {
     return Gen<Result<Value, Failure>>.frequency(
       (1, gen.map { Result.failure($0) }),
@@ -485,7 +453,6 @@ extension Gen where Value: Hashable {
   /// - Parameter count: The size of the random set.
   /// - Returns: A generator of sets.
   @inlinable
-  @Sendable
   public func set(ofAtMost count: Gen<Int>) -> Gen<Set<Value>> {
     return count.flatMap { count in
       guard count > 0 else { return .always([]) }
@@ -506,7 +473,6 @@ extension Gen<UnicodeScalar> {
   /// - Parameter range: The range in which to create a random unicode scalar. `range` must be finite.
   /// - Returns: A generator of random unicode scalars within the bounds of range.
   @inlinable
-  @Sendable
   public static func unicodeScalar(in range: ClosedRange<Value>) -> Gen {
     return Gen<UInt32>
       .int(in: range.lowerBound.value...range.upperBound.value)
@@ -521,7 +487,6 @@ extension Gen<Character> {
   /// - Parameter range: The range in which to create a random character. `range` must be finite.
   /// - Returns: A generator of random characters within the bounds of range.
   @inlinable
-  @Sendable
   public static func character(in range: ClosedRange<Value>) -> Gen {
     return Gen<UnicodeScalar>
       .unicodeScalar(
@@ -564,7 +529,6 @@ extension Gen<Character> {
   /// - Parameter count: The size of the random string.
   /// - Returns: A generator of strings.
   @inlinable
-  @Sendable
   public func string(of count: Gen<Int>) -> Gen<String> {
     return self
       .map { String($0) }
diff --git a/Sources/Gen/Zip.swift b/Sources/Gen/Zip.swift
index 24cb696..3c6839c 100644
--- a/Sources/Gen/Zip.swift
+++ b/Sources/Gen/Zip.swift
@@ -5,7 +5,6 @@
 ///   - b: A generator of `B`s.
 /// - Returns: A generator of `(A, B)` pairs.
 @inlinable
-@Sendable
 public func zip<A, B>(_ a: Gen<A>, _ b: Gen<B>) -> Gen<(A, B)> {
   return Gen<(A, B)> { rng in
     (a._run(&rng), b._run(&rng))
@@ -13,7 +12,6 @@ public func zip<A, B>(_ a: Gen<A>, _ b: Gen<B>) -> Gen<(A, B)> {
 }
 
 @inlinable
-@Sendable
 public func zip<A, B, C>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -25,7 +23,6 @@ public func zip<A, B, C>(
 }
 
 @inlinable
-@Sendable
 public func zip<A, B, C, D>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -38,7 +35,6 @@ public func zip<A, B, C, D>(
 }
 
 @inlinable
-@Sendable
 public func zip<A, B, C, D, E>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -52,7 +48,6 @@ public func zip<A, B, C, D, E>(
 }
 
 @inlinable
-@Sendable
 public func zip<A, B, C, D, E, F>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -67,7 +62,6 @@ public func zip<A, B, C, D, E, F>(
 }
 
 @inlinable
-@Sendable
 public func zip<A, B, C, D, E, F, G>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -83,7 +77,6 @@ public func zip<A, B, C, D, E, F, G>(
 }
 
 @inlinable
-@Sendable
 public func zip<A, B, C, D, E, F, G, H>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -100,7 +93,6 @@ public func zip<A, B, C, D, E, F, G, H>(
 }
 
 @inlinable
-@Sendable
 public func zip<A, B, C, D, E, F, G, H, I>(
   _ a: Gen<A>,
   _ b: Gen<B>,
@@ -118,7 +110,6 @@ public func zip<A, B, C, D, E, F, G, H, I>(
 }
 
 @inlinable
-@Sendable
 public func zip<A, B, C, D, E, F, G, H, I, J>(
   _ a: Gen<A>,
   _ b: Gen<B>,

From 09e9641b2214b94f830e4c43de3a1900a9dd2318 Mon Sep 17 00:00:00 2001
From: seanmrich <sean.rich.register@mac.com>
Date: Fri, 11 Oct 2024 06:19:12 -0400
Subject: [PATCH 4/5] Update ci.yml

---
 .github/workflows/ci.yml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7d06236..32ebf68 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -29,6 +29,8 @@ jobs:
     container: swift:${{ matrix.swift }}
     steps:
     - uses: actions/checkout@v4
+    - name: Install dependencies
+      run: apt-get update && apt-get install -y make
     - name: Run tests
       run: make test-linux
     - name: Build for release

From afb216f138a00b9e04f1ed29df5186fb5a6716df Mon Sep 17 00:00:00 2001
From: seanmrich <sean.rich.register@mac.com>
Date: Fri, 11 Oct 2024 06:31:25 -0400
Subject: [PATCH 5/5] Update ci.yml

---
 .github/workflows/ci.yml | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 32ebf68..74d27e2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -29,9 +29,7 @@ jobs:
     container: swift:${{ matrix.swift }}
     steps:
     - uses: actions/checkout@v4
-    - name: Install dependencies
-      run: apt-get update && apt-get install -y make
     - name: Run tests
-      run: make test-linux
-    - name: Build for release
-      run: make build-release-linux
+      run: swift test --parallel
+    - name: Run tests (release)
+      run: swift test -c release --parallel