Swift Package manager : static build failing after software updates

Question

Problem Description

One project I'm working on isn't building since I updated Xcode. Note that I am building the exécutable with swift build (not Xcode).

Details

The command that is failing is : swift build -Xswiftc -static-stdlib -Xswiftc -DDEBUG

I am trying to make a static build. When just try swift build, it works.

The error

I'm copying the beginning of the error output only (the rest is too long):

ld: warning: directory not found for option '-L/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift_static/macosx'
ld: warning: Could not find auto-linked library 'swiftFoundation'
ld: warning: Could not find auto-linked library 'swiftDarwin'
ld: warning: Could not find auto-linked library 'swiftCoreFoundation'
ld: warning: Could not find auto-linked library 'swiftIOKit'
ld: warning: Could not find auto-linked library 'swiftQuartzCore'
ld: warning: Could not find auto-linked library 'swiftCore'
ld: warning: Could not find auto-linked library 'swiftCoreGraphics'
ld: warning: Could not find auto-linked library 'swiftObjectiveC'
ld: warning: Could not find auto-linked library 'swiftDispatch'
ld: warning: Could not find auto-linked library 'swiftCoreData'
ld: warning: Could not find auto-linked library 'swiftSwiftOnoneSupport'
ld: warning: Could not find auto-linked library 'swiftXPC'
ld: warning: Could not find auto-linked library 'swiftMetal'
ld: warning: Could not find auto-linked library 'swiftAppKit'
ld: warning: Could not find auto-linked library 'swiftCoreImage'
Undefined symbols for architecture x86_64:

Package.swift

Note that I've renamed the project and library names for anonymity.

// swift-tools-version:4.0
// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription

let package = Package(
    name: "PROJECT",
    dependencies: [
        // Dependencies declare other packages that this package depends on.
        // .package(url: /* package url */, from: "1.0.0"),
        .package(url: "../Lib1", .branch("master")),
        .package(url: "../Lib2", .branch("master")),
        .package(url: "../Lib3", .branch("master")),
        .package(url: "../Lib4", .branch("master")),
    ],
    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: "PROJECT",
            dependencies: ["Lib1", "Lib2", "Lib3", "Lib4"]),
    ]
)

Swift version after update

Running

swift -version

in the command line returns :

Apple Swift version 5.0 (swiftlang-1001.0.69.5 clang-1001.0.46.3)
Target: x86_64-apple-darwin18.2.0

Answer 1

Static building isn't supported on new versions of MacOS. See answer here :

https://forums.swift.org/t/swift-package-manager-static-build-failing-after-software-updates/25694