Unused products/targets contribute to naming conflicts in SwiftPM

Using Swift
1

I like the SE-0339 feature very much. However, I found it not always applicable to use moduleAliases in some situations, here is an example:

In the first place, we have a bottom-layer package, described as follows

let package = Package(
    name: "Game",
    products: [
        .library(name: "Game", targets: ["Game"]),
        .library(name: "Utils", targets: ["Utils"]),
    ],
    targets: [
        .target(name: "Game"),
        .target(name: "Utils")
    ]
)

It just declares 2 independent targets and the corresponding products.

This package is then being used by an upper-layer package, described as follows

let package = Package(
    name: "App",
    dependencies: [.package(path: "../Game")],
    targets: [
        .executableTarget(
            name: "App",
            dependencies: [
                .target(name: "Utils"),
                .product(name: "Game", package: "Game")
            ]
        ),

        .target(name: "Utils"),
    ]
)

This package declares a target Utils, which has the same name with the one in the bottom-layer package. However, package App never references Game/Utils, so theoretically, there should not be two targets sharing a same name in the dependency graph.

Nevertheless, when we run swift build for the above example, there will be an error:

error: multiple packages ('app', 'game') declare targets with a conflicting name: 'Utils’; 
target names need to be unique across the package graph

What's worse, there's no way to workaround this issue, because there's no place to pass a moduleAliases argument to SwiftPM. If we try to do that in package App by writing

.product(name: "Game", package: "Game", moduleAliases: ["Utils": "GameUtils"])

that'll only create one additional warning, saying

warning: module alias for target 'Utils', declared in package 'app', 
does not match any recursive target dependency of product 'Game' from package 'Game'

So, is this just a bug, or a temporary implementation limitation?

1 Like
2

Either way, do you know of existing reports on the SwiftPM GitHub repository tracking this? If not, would you mind filing one?

4

Thanks, that's done Unused products/targets should not contribute to naming conflicts. · Issue #8482 · swiftlang/swift-package-manager · GitHub