Merge pull request #132 from dmhts/fix-duplicate-build-products

Fix: Duplicate build products in swift-6.0-DEVELOPMENT-SNAPSHOTs

Sources/ScipioKit/DescriptionPackage.swift

@@ -241,4 +241,22 @@ struct BuildProduct: Hashable, Sendable {
     var binaryTarget: BinaryTarget? {
         target.underlyingTarget as? BinaryTarget
     }
+
+    func hash(into hasher: inout Hasher) {
+        // Important: Relevant for swift-6.0+ toolchain versions. For the versions below
+        // this change has no effect as SwiftPM provides its own proper `Hashable`
+        // implementations for both `ResolvedPackage` and `ResolvedTarget`.
+        //
+        // We cannot directly use `ResolvedModule.id` here as `id` also includes `BuildTriple`.
+        // The reason for this is that `ResolvedModule.buildTriple` is parent-dependent; more
+        // specifically, the same `ResolvedModule` will have a different build triple depending
+        // on whether it is in a root or dependency position.
+        // For more context, see `ResolvedModule.updateBuildTriplesOfDependencies`.
+        //
+        // At the same time, build triples remain irrelevant for the `Scipio` use case where the 
+        // build product must be the same regardless of the triple. Meanwhile, the target name and
+        // package identity remain relevant and unambiguously identify the build product.
+        hasher.combine(target.name)
+        hasher.combine(package.identity)
+    }
 }

Tests/ScipioKitTests/DescriptionPackageTests.swift

@@ -74,11 +74,14 @@ final class DescriptionPackageTests: XCTestCase {
         XCTAssertEqual(package.name, "TestingPackage")
 
         XCTAssertEqual(
-            Set(try package.resolveBuildProducts().map(\.target.name)),
+            try package.resolveBuildProducts().map(\.target.name),
             [
                 "Logging",
-                "TestingPackage",
-            ]
+                "MyTarget",
+                "ExecutableTarget",
+                "MyPlugin",
+            ],
+            "Order of the resolved products should be correct"
         )
     }
 

Tests/ScipioKitTests/Resources/Fixtures/TestingPackage/Package.swift

@@ -10,20 +10,38 @@ let package = Package(
         // Products define the executables and libraries a package produces, and make them visible to other packages.
         .library(
             name: "TestingPackage",
-            targets: ["TestingPackage"]),
+            targets: ["MyTarget"]
+        ),
+        .plugin(
+            name: "MyPlugin",
+            targets: ["MyPlugin"]
+        )
     ],
     dependencies: [
         .package(url: "https://github.com/apple/swift-log.git", .upToNextMinor(from: "1.4.4")),
     ],
     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 this package depends on.
+        // Directly exported targets
         .target(
-            name: "TestingPackage",
+            name: "MyTarget",
             dependencies: [
                 .product(name: "Logging", package: "swift-log"),
             ]
         ),
+        .plugin(
+            name: "MyPlugin",
+            capability: .command(
+                intent: .custom(
+                    verb: "my-plugin-verb",
+                    description: "my-plugin-description")),
+            dependencies: ["ExecutableTarget"]
+        ),
+        // Transitevly exported targets
+        .executableTarget(
+            name: "ExecutableTarget",
+            dependencies: ["MyTarget"]
+        ),
+        // Not exported (internal) targets
         .executableTarget(
             name: "InternalExecutableTarget",
             dependencies: ["InternalRegularTarget"]

Tests/ScipioKitTests/Resources/Fixtures/TestingPackage/Plugins/MyPlugin/MyPlugin.swift

@@ -0,0 +1,6 @@
+import PackagePlugin
+
+@main
+struct MyPlugin: CommandPlugin {
+    func performCommand(context: PluginContext, arguments: [String]) async throws {}
+}

Tests/ScipioKitTests/Resources/Fixtures/TestingPackage/Sources/ExecutableTarget/ExternalExecutableTarget.swift

@@ -0,0 +1,4 @@
+@main
+public struct ExecutableTarget {
+    static func main() {}
+}