Lower Swift version requirement to 5.0

.travis.yml

@@ -3,17 +3,8 @@ language: generic
 addons:
   apt:
     packages:
-      - build-essential
       - clang
-      - curl
-      - gpg-agent
-      - libcurl4
       - libicu-dev
-      - libpython2.7
-      - libxml2
-      - libz-dev
-      - pkg-config
-      - software-properties-common
   homebrew:
     packages:
       - swiftformat
@@ -34,20 +25,47 @@ jobs:
       osx_image: xcode11
       script: make pretest
 
-    - stage: test
+    - &linux
+      stage: test
       name: Ubuntu 18.04 / Swift 5.1
       os: linux
       dist: bionic
+      env:
+        - LINUX_TOOLCHAIN_URL=https://swift.org/builds/swift-5.1-branch/ubuntu1804/swift-5.1-DEVELOPMENT-SNAPSHOT-2019-08-17-a/swift-5.1-DEVELOPMENT-SNAPSHOT-2019-08-17-a-ubuntu18.04.tar.gz
       before_install: export PATH="${TRAVIS_BUILD_DIR}/usr/bin":"${PATH}"
-      install: make toolchain-bionic
+      install: make LINUX_TOOLCHAIN_URL=$LINUX_TOOLCHAIN_URL toolchain
       script: make test
 
-    - stage: test
+    - <<: *linux
+      name: Ubuntu 18.04 / Swift 5.0
+      env:
+        - LINUX_TOOLCHAIN_URL=https://swift.org/builds/swift-5.0.2-release/ubuntu1804/swift-5.0.2-RELEASE/swift-5.0.2-RELEASE-ubuntu18.04.tar.gz
+      script: make test-nosanitize
+
+    - <<: *linux
+      name: Ubuntu 16.04 / Swift 5.1
+      dist: xenial
+      env:
+        - LINUX_TOOLCHAIN_URL=https://swift.org/builds/swift-5.1-branch/ubuntu1604/swift-5.1-DEVELOPMENT-SNAPSHOT-2019-08-17-a/swift-5.1-DEVELOPMENT-SNAPSHOT-2019-08-17-a-ubuntu16.04.tar.gz
+
+    - <<: *linux
+      name: Ubuntu 16.04 / Swift 5.0
+      dist: xenial
+      env:
+        - LINUX_TOOLCHAIN_URL=https://swift.org/builds/swift-5.0.2-release/ubuntu1604/swift-5.0.2-RELEASE/swift-5.0.2-RELEASE-ubuntu16.04.tar.gz
+      script: make test-nosanitize
+
+    - &macos
+      stage: test
       name: macOS 10.14 / Xcode 11.0
       os: osx
       osx_image: xcode11
       script: make test
 
+    - <<: *macos
+      name: macOS 10.14 / Xcode 10.3
+      osx_image: xcode10.3
+
     - stage: release
       name: Documentation
       os: osx

Makefile

@@ -5,9 +5,9 @@ SHELL = /bin/sh
 MODULES = Futures FuturesSync
 FOLDERS = Sources Tests
 
-LINUX_DEV_TOOLCHAIN_URL = https://swift.org/builds/swift-5.1-branch/ubuntu1804/swift-5.1-DEVELOPMENT-SNAPSHOT-2019-08-17-a/swift-5.1-DEVELOPMENT-SNAPSHOT-2019-08-17-a-ubuntu18.04.tar.gz
-LINUX_DEV_IMAGE_NAME = swift-futures
-LINUX_DEV_IMAGE_TAG = 5.1-dev
+LINUX_TOOLCHAIN_URL = https://swift.org/builds/swift-5.1-branch/ubuntu1804/swift-5.1-DEVELOPMENT-SNAPSHOT-2019-08-17-a/swift-5.1-DEVELOPMENT-SNAPSHOT-2019-08-17-a-ubuntu18.04.tar.gz
+LINUX_IMAGE_NAME = swift-futures
+LINUX_IMAGE_TAG = 5.1-dev
 
 SWIFT := $(shell command -v swift 2>/dev/null)
 SWIFTFORMAT := $(shell command -v swiftformat 2>/dev/null)
@@ -25,6 +25,9 @@ build-release:
 test:
 	$(SWIFT) test --configuration debug --sanitize thread
 
+test-nosanitize:
+	$(SWIFT) test --configuration debug
+
 test-release:
 	$(SWIFT) test --configuration release
 
@@ -37,7 +40,7 @@ clean:
 precommit: gyb tests format lint
 pretest: gyb tests format pristine lint
 
-.PHONY: build test build-release test-release repl clean precommit pretest
+.PHONY: build build-release test test-nosanitize test-release repl clean precommit pretest
 
 
 xcodeproj:
@@ -81,10 +84,10 @@ endif
 .PHONY: docs
 
 
-toolchain-bionic:
-	Scripts/install-toolchain.sh "$(LINUX_DEV_TOOLCHAIN_URL)"
+toolchain:
+	Scripts/install-toolchain.sh "$(LINUX_TOOLCHAIN_URL)"
 
-.PHONY: toolchain-bionic
+.PHONY: toolchain
 
 
 _docker:
@@ -93,15 +96,15 @@ ifndef DOCKER
 endif
 
 linuximage: _docker
-	$(DOCKER) build --tag '$(LINUX_DEV_IMAGE_NAME):$(LINUX_DEV_IMAGE_TAG)' --build-arg TOOLCHAIN_URL="$(LINUX_DEV_TOOLCHAIN_URL)" .
+	$(DOCKER) build --tag '$(LINUX_IMAGE_NAME):$(LINUX_IMAGE_TAG)' --build-arg TOOLCHAIN_URL="$(LINUX_TOOLCHAIN_URL)" .
 
 linuxtest: _docker
 	cwd=$$(pwd); \
-	$(DOCKER) run -it --rm --privileged --volume "$${cwd}:/src" '$(LINUX_DEV_IMAGE_NAME):$(LINUX_DEV_IMAGE_TAG)' test --configuration debug --sanitize thread
+	$(DOCKER) run -it --rm --privileged --volume "$${cwd}:/src" '$(LINUX_IMAGE_NAME):$(LINUX_IMAGE_TAG)' test --configuration debug --sanitize thread
 
 linuxrepl: _docker
 	cwd=$$(pwd); \
-	$(DOCKER) run -it --rm --privileged --volume "$${cwd}:/src" '$(LINUX_DEV_IMAGE_NAME):$(LINUX_DEV_IMAGE_TAG)' run --repl --configuration debug
+	$(DOCKER) run -it --rm --privileged --volume "$${cwd}:/src" '$(LINUX_IMAGE_NAME):$(LINUX_IMAGE_TAG)' run --repl --configuration debug
 
 .PHONY: _docker linuximage linuxtest linuxrepl
 

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.1
+// swift-tools-version:5.0
 
 import PackageDescription
 

README.md

@@ -12,7 +12,7 @@ cancellation and threading, trivial.
 <p>
 <img src="https://img.shields.io/travis/dfunckt/swift-futures/master">
 <img src="https://img.shields.io/github/v/release/dfunckt/swift-futures?sort=semver">
-<img src="https://img.shields.io/badge/swift-%3E%3D5.1-orange">
+<img src="https://img.shields.io/badge/swift-%3E%3D5.0-orange">
 <img src="https://img.shields.io/badge/platform-Linux%20macOS%20iOS%20tvOS%20watchOS-blue">
 </p>
 
@@ -185,7 +185,7 @@ func isPronic(_ n: Int) -> Bool {
 
 ### Requirements
 
-Futures requires *Swift 5.1* (or newer) and can be deployed to any of the
+Futures requires *Swift 5.0* (or newer) and can be deployed to any of the
 following platforms:
 
 - macOS 10.12+
@@ -218,7 +218,7 @@ exports two separate modules:
 Here is an example `Package.swift`:
 
 ```swift
-// swift-tools-version:5.1
+// swift-tools-version:5.0
 import PackageDescription
 
 let package = Package(

Sources/Futures/Channel.swift

@@ -53,14 +53,13 @@ extension Channel {
     public enum Unbuffered<Item>: ChannelProtocol {
         public typealias Buffer = _Private.SlotBounded<Item>
         public typealias Park = _Private.SPSCPark
-        @usableFromInline typealias _Impl = _Private.Impl<Self>
     }
 
     /// Creates a bounded, single-slot, single-sender (AKA "rendez-vous")
     /// channel. Unbuffered channels are safe to use from any executor.
     @inlinable
     public static func makeUnbuffered<T>(itemType _: T.Type = T.self) -> Pipe<Unbuffered<T>> {
-        let impl = Unbuffered<T>._Impl(buffer: .init(), park: .init())
+        let impl = _Private.Impl<Unbuffered<T>>(buffer: .init(), park: .init())
         return .init(tx: .init(impl), rx: .init(impl))
     }
 }
@@ -73,14 +72,13 @@ extension Channel {
     public enum Passthrough<Item>: UnboundedChannelProtocol {
         public typealias Buffer = _Private.SlotUnbounded<Item>
         public typealias Park = _Private.SPSCPark
-        @usableFromInline typealias _Impl = _Private.Impl<Self>
     }
 
     /// Creates an unbounded, single-slot, single-sender (AKA "passthrough")
     /// channel. Passthrough channels must only be used from a single executor.
     @inlinable
     public static func makePassthrough<T>(itemType _: T.Type = T.self) -> Pipe<Passthrough<T>> {
-        let impl = Passthrough<T>._Impl(buffer: .init(), park: .init())
+        let impl = _Private.Impl<Passthrough<T>>(buffer: .init(), park: .init())
         return .init(tx: .init(impl), rx: .init(impl))
     }
 }
@@ -93,14 +91,13 @@ extension Channel {
     public enum Buffered<Item>: ChannelProtocol {
         public typealias Buffer = _Private.SPSCBufferBounded<Item>
         public typealias Park = _Private.SPSCPark
-        @usableFromInline typealias _Impl = _Private.Impl<Self>
     }
 
     /// Creates a bounded, buffered, single-sender channel with the specified
     /// capacity. Buffered channels are safe to use from any executor.
     @inlinable
     public static func makeBuffered<T>(itemType _: T.Type = T.self, capacity: Int) -> Pipe<Buffered<T>> {
-        let impl = Buffered<T>._Impl(buffer: .init(capacity: capacity), park: .init())
+        let impl = _Private.Impl<Buffered<T>>(buffer: .init(capacity: capacity), park: .init())
         return .init(tx: .init(impl), rx: .init(impl))
     }
 }
@@ -113,14 +110,13 @@ extension Channel {
     public enum BufferedUnbounded<Item>: UnboundedChannelProtocol {
         public typealias Buffer = _Private.SPSCBufferUnbounded<Item>
         public typealias Park = _Private.SPSCPark
-        @usableFromInline typealias _Impl = _Private.Impl<Self>
     }
 
     /// Creates an unbounded, buffered, single-sender channel. Buffered channels
     /// are safe to use from any executor.
     @inlinable
     public static func makeBuffered<T>(itemType _: T.Type = T.self) -> Pipe<BufferedUnbounded<T>> {
-        let impl = BufferedUnbounded<T>._Impl(buffer: .init(), park: .init())
+        let impl = _Private.Impl<BufferedUnbounded<T>>(buffer: .init(), park: .init())
         return .init(tx: .init(impl), rx: .init(impl))
     }
 }
@@ -133,14 +129,13 @@ extension Channel {
     public enum Shared<Item>: ChannelProtocol {
         public typealias Buffer = _Private.MPSCBufferBounded<Item>
         public typealias Park = _Private.MPSCPark
-        @usableFromInline typealias _Impl = _Private.Impl<Self>
     }
 
     /// Creates a bounded, buffered, multiple-sender channel with the specified
     /// capacity. Shared channels are safe to use from any executor.
     @inlinable
     public static func makeShared<T>(itemType _: T.Type = T.self, capacity: Int) -> Pipe<Shared<T>> {
-        let impl = Shared<T>._Impl(buffer: .init(capacity: capacity), park: .init())
+        let impl = _Private.Impl<Shared<T>>(buffer: .init(capacity: capacity), park: .init())
         return .init(tx: .init(impl), rx: .init(impl))
     }
 }
@@ -153,14 +148,13 @@ extension Channel {
     public enum SharedUnbounded<Item>: UnboundedChannelProtocol {
         public typealias Buffer = _Private.MPSCBufferUnbounded<Item>
         public typealias Park = _Private.MPSCPark
-        @usableFromInline typealias _Impl = _Private.Impl<Self>
     }
 
     /// Creates an unbounded, buffered, multiple-sender channel. Shared channels
     /// are safe to use from any executor.
     @inlinable
     public static func makeShared<T>(itemType _: T.Type = T.self) -> Pipe<SharedUnbounded<T>> {
-        let impl = SharedUnbounded<T>._Impl(buffer: .init(), park: .init())
+        let impl = _Private.Impl<SharedUnbounded<T>>(buffer: .init(), park: .init())
         return .init(tx: .init(impl), rx: .init(impl))
     }
 }

Sources/Futures/Internal/TaskScheduler.swift

@@ -184,17 +184,17 @@ private final class _ReadyQueue<F: FutureProtocol> {
         }
 
         var future: F? {
-            get { withUnsafeMutablePointerToHeader { $0.pointee.future } }
+            get { return withUnsafeMutablePointerToHeader { $0.pointee.future } }
             set { withUnsafeMutablePointerToHeader { $0.pointee.future = newValue } }
         }
 
         var prevActive: Node? {
-            get { withUnsafeMutablePointerToHeader { $0.pointee.prevActive } }
+            get { return withUnsafeMutablePointerToHeader { $0.pointee.prevActive } }
             set { withUnsafeMutablePointerToHeader { $0.pointee.prevActive = newValue } }
         }
 
         var nextActive: Node? {
-            get { withUnsafeMutablePointerToHeader { $0.pointee.nextActive } }
+            get { return withUnsafeMutablePointerToHeader { $0.pointee.nextActive } }
             set { withUnsafeMutablePointerToHeader { $0.pointee.nextActive = newValue } }
         }
 

Sources/Futures/Result.swift

@@ -13,7 +13,7 @@ extension AnyFuture {
     public init<T>(_ pollFn: @escaping (inout Context) throws -> Poll<T>) where Output == Result<T, Error> {
         self.init { context in
             do {
-                return try pollFn(&context).map(Result.success)
+                return try pollFn(&context).map { .success($0) }
             } catch {
                 return .ready(.failure(error))
             }
@@ -27,7 +27,7 @@ extension AnyStream {
         self.init { context in
             do {
                 return try pollNextFn(&context).map {
-                    $0.map(Result.success)
+                    $0.map { .success($0) }
                 }
             } catch {
                 return .ready(.failure(error))