- Limit the fix to tools-version 5.9

- Add minimum deployment target to example

Author: neonichu

Fixtures/Miscellaneous/Plugins/IncorrectDependencies/Package.swift

@@ -1,8 +1,11 @@
-// swift-tools-version:5.8
+// swift-tools-version:5.9
 import PackageDescription
 
 let package = Package(
     name: "111920845-sample",
+    platforms: [
+        .macOS(.v10_15), // example uses swift concurrency which is only available in 10.15 or newer
+    ],
     products: [
         .executable(name: "MyPluginExecutable", targets: ["MyPluginExecutable"]),
         .plugin(name: "MyPlugin", targets: ["MyPlugin"]),

Sources/Build/BuildPlan.swift

@@ -695,14 +695,22 @@ public class BuildPlan: SPMBuildCore.BuildPlan {
         libraryBinaryPaths: Set<AbsolutePath>,
         availableTools: [String: AbsolutePath]
     ) {
+        /* Prior to tools-version 5.9, we used to errorneously recursively traverse plugin dependencies and statically include their
+         targets. For compatibility reasons, we preserve that behavior for older tools-versions. */
+        let shouldExcludePlugins: Bool
+        if let toolsVersion = self.graph.package(for: product)?.manifest.toolsVersion {
+            shouldExcludePlugins = toolsVersion >= .v5_9
+        } else {
+            shouldExcludePlugins = false
+        }
 
         // Sort the product targets in topological order.
         let nodes: [ResolvedTarget.Dependency] = product.targets.map { .target($0, conditions: []) }
         let allTargets = try topologicalSort(nodes, successors: { dependency in
             switch dependency {
             // Include all the dependencies of a target.
             case .target(let target, _):
-                if [.macro, .plugin].contains(target.type) {
+                if shouldExcludePlugins, [.macro, .plugin].contains(target.type) {
                     return []
                 }
                 return target.dependencies.filter { $0.satisfies(self.buildEnvironment) }
@@ -714,10 +722,13 @@ public class BuildPlan: SPMBuildCore.BuildPlan {
                     return []
                 }
 
+                let productDependencies: [ResolvedTarget.Dependency] = product.targets.map { .target($0, conditions: []) }
                 switch product.type {
                 case .library(.automatic), .library(.static):
-                    return product.targets.map { .target($0, conditions: []) }
-                case .library(.dynamic), .test, .executable, .snippet, .macro, .plugin:
+                    return productDependencies
+                case .plugin:
+                    return shouldExcludePlugins ? [] : productDependencies
+                case .library(.dynamic), .test, .executable, .snippet, .macro:
                     return []
                 }
             }