Avoid redundant traversal when computing static transitive dependencies

Each target's static transitive linked dependencies were computed by running transitiveClosure once per direct dependency. Whenever several direct dependencies reached the same subgraph, that subgraph was traversed once for each of them, which was redundant work that did not affect the result.

Seed a single transitiveClosure with all direct dependencies at once so each node is visited only once. The resulting set of dependencies is unchanged.

Author: yimajo

Sources/SWBTaskConstruction/ProductPlanning/ProductPlan.swift

@@ -561,15 +561,13 @@ package final class GlobalProductPlan: GlobalTargetInfoProvider
                     }
 
                     let linkedDependencies: [LinkedDependency] = linkageGraph.dependencies(of: configuredTarget).map { .direct($0) }
-                    let transitiveStaticDependencies: [LinkedDependency] = linkedDependencies.flatMap { origin in
-                        transitiveClosure([origin.target]) {
-                            let settings = planRequest.buildRequestContext.getCachedSettings($0.parameters, target: $0.target)
-                            guard !Self.dynamicMachOTypes.contains(settings.globalScope.evaluate(BuiltinMacros.MACH_O_TYPE)) else {
-                                return []
-                            }
-                            return linkageGraph.dependencies(of: $0)
-                        }.0.map { .staticTransitive($0) }
-                    }
+                    let transitiveStaticDependencies: [LinkedDependency] = transitiveClosure(linkedDependencies.map(\.target)) {
+                        let settings = planRequest.buildRequestContext.getCachedSettings($0.parameters, target: $0.target)
+                        guard !Self.dynamicMachOTypes.contains(settings.globalScope.evaluate(BuiltinMacros.MACH_O_TYPE)) else {
+                            return []
+                        }
+                        return linkageGraph.dependencies(of: $0)
+                    }.0.map { .staticTransitive($0) }
 
                     directlyLinkedDependenciesByTarget[configuredTarget] = OrderedSet(linkedDependencies + transitiveStaticDependencies + (bundleLoaderByTarget[configuredTarget].map { [.bundleLoader($0)] } ?? []))
                     impartedBuildPropertiesByTarget[configuredTarget] = dependencies.compactMap { $0.getImpartedBuildProperties(using: planRequest) }