Swift 包管理器：依赖 iOS 版本

Question

我正在尝试使用 xCode11 beta 7构建具有外部依赖项 ( CoreStore ) 的swift 包。我的包针对 iOS11+，它在Package.swift以下位置声明：

// swift-tools-version:5.1
// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription

let package = Package(
    name: "Storages",
    platforms: [.iOS(.v11)],
    products: [
        // Products define the executables and libraries produced by a package, and make them visible to other packages.
        .library(
            name: "Storages",
            targets: ["Storages"]),
    ],
    dependencies: [
        // Dependencies declare other packages that this package depends on.
        .package(url: "https://github.com/JohnEstropia/CoreStore.git", from: "6.3.0")
    ],
    targets: [
        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
        // Targets can depend on other targets in this package, and on products in packages which this package depends on.
        .target(
            name: "Storages",
            dependencies: [.product(name: "CoreStore")]),

        .testTarget(
            name: "StoragesTests",
            dependencies: ["Storages"]),
    ]
)

但是，当我构建它时，没有指定 iOS 版本的依赖项构建，所以我得到兼容性错误： "'uniquenessConstraints' is only available in iOS 9.0 or newer"等等。

我该如何解决？看起来是 xCode11 错误，但我不确定。

Answer 1

在我的机器上，将platforms:参数添加到清单中解决了这个问题。例如：

let package = Package(
    name: "MyLibrary",
    platforms: [.iOS("13.0")],
    // ...

Answer 2

我不确定这是否是 xCode bug，但是使用 Swift Package Manager 和 xCode 11，您必须在使用#available检查时明确指定 iOS 版本。不管库是否针对 iOS 10+，而不是

if #available(macOS 10.11, *) {
    info.append(("uniquenessConstraints", self.uniquenessConstraints))
}

你应该使用

if #available(macOS 10.11, iOS 9.0, *) {
    info.append(("uniquenessConstraints", self.uniquenessConstraints))
}

拉取请求已发布： https://github.com/JohnEstropia/CoreStore/pull/341