Implement topologicalSort inside BuildSystemManager using dependency information

Sources/BuildSystemIntegration/SwiftPMBuildSystem.swift

@@ -210,10 +210,8 @@ package actor SwiftPMBuildSystem {
   /// Maps source and header files to the target that include them.
   private var fileToTargets: [DocumentURI: Set<BuildTargetIdentifier>] = [:]
 
-  /// Maps target ids to their SwiftPM build target as well as the depth at which they occur in the build
-  /// graph. Top level targets on which no other target depends have a depth of `1`. Targets with dependencies have a
-  /// greater depth.
-  private var targets: [BuildTargetIdentifier: (buildTarget: SwiftBuildTarget, depth: Int)] = [:]
+  /// Maps target ids to their SwiftPM build target.
+  private var swiftPMTargets: [BuildTargetIdentifier: SwiftBuildTarget] = [:]
 
   private var targetDependencies: [BuildTargetIdentifier: Set<BuildTargetIdentifier>] = [:]
 
@@ -442,7 +440,7 @@ extension SwiftPMBuildSystem {
     /// properties because otherwise we might end up in an inconsistent state
     /// with only some properties modified.
 
-    self.targets = [:]
+    self.swiftPMTargets = [:]
     self.fileToTargets = [:]
     self.targetDependencies = [:]
 
@@ -451,10 +449,7 @@ extension SwiftPMBuildSystem {
       guard let targetIdentifier else {
         return
       }
-      var depth = depth
-      if let existingDepth = targets[targetIdentifier]?.depth {
-        depth = max(existingDepth, depth)
-      } else {
+      if swiftPMTargets[targetIdentifier] == nil {
         for source in buildTarget.sources + buildTarget.headers {
           fileToTargets[DocumentURI(source), default: []].insert(targetIdentifier)
         }
@@ -464,7 +459,7 @@ extension SwiftPMBuildSystem {
       {
         self.targetDependencies[parentIdentifier, default: []].insert(targetIdentifier)
       }
-      targets[targetIdentifier] = (buildTarget, depth)
+      swiftPMTargets[targetIdentifier] = buildTarget
     }
 
     await messageHandler?.sendNotificationToSourceKitLSP(DidChangeBuildTargetNotification(changes: nil))
@@ -523,9 +518,9 @@ extension SwiftPMBuildSystem: BuildSystemIntegration.BuiltInBuildSystem {
   }
 
   package func buildTargets(request: BuildTargetsRequest) async throws -> BuildTargetsResponse {
-    let targets = self.targets.map { (targetId, target) in
+    let targets = self.swiftPMTargets.map { (targetId, target) in
       var tags: [BuildTargetTag] = [.test]
-      if target.depth != 1 {
+      if !target.isPartOfRootPackage {
         tags.append(.dependency)
       }
       return BuildTarget(
@@ -547,10 +542,10 @@ extension SwiftPMBuildSystem: BuildSystemIntegration.BuiltInBuildSystem {
     // TODO: Query The SwiftPM build system for the document's language and add it to SourceItem.data
     // (https://github.com/swiftlang/sourcekit-lsp/issues/1267)
     for target in request.targets {
-      guard let swiftPMTarget = self.targets[target] else {
+      guard let swiftPMTarget = self.swiftPMTargets[target] else {
         continue
       }
-      let sources = swiftPMTarget.buildTarget.sources.map {
+      let sources = swiftPMTarget.sources.map {
         SourceItem(uri: DocumentURI($0), kind: .file, generated: false)
       }
       result.append(SourcesItem(target: target, sources: sources))
@@ -568,13 +563,13 @@ extension SwiftPMBuildSystem: BuildSystemIntegration.BuiltInBuildSystem {
       return try settings(forPackageManifest: path)
     }
 
-    guard let buildTarget = self.targets[request.target]?.buildTarget else {
+    guard let swiftPMTarget = self.swiftPMTargets[request.target] else {
       logger.fault("Did not find target \(request.target.forLogging)")
       return nil
     }
 
-    if !buildTarget.sources.lazy.map(DocumentURI.init).contains(request.textDocument.uri),
-      let substituteFile = buildTarget.sources.sorted(by: { $0.path < $1.path }).first
+    if !swiftPMTarget.sources.lazy.map(DocumentURI.init).contains(request.textDocument.uri),
+      let substituteFile = swiftPMTarget.sources.sorted(by: { $0.path < $1.path }).first
     {
       logger.info("Getting compiler arguments for \(url) using substitute file \(substituteFile)")
       // If `url` is not part of the target's source, it's most likely a header file. Fake compiler arguments for it
@@ -585,7 +580,7 @@ extension SwiftPMBuildSystem: BuildSystemIntegration.BuiltInBuildSystem {
       // getting its compiler arguments and then patching up the compiler arguments by replacing the substitute file
       // with the `.cpp` file.
       let buildSettings = FileBuildSettings(
-        compilerArguments: try await compilerArguments(for: DocumentURI(substituteFile), in: buildTarget),
+        compilerArguments: try await compilerArguments(for: DocumentURI(substituteFile), in: swiftPMTarget),
         workingDirectory: projectRoot.pathString
       ).patching(newFile: try resolveSymlinks(path).pathString, originalFile: substituteFile.absoluteString)
       return SourceKitOptionsResponse(
@@ -595,7 +590,7 @@ extension SwiftPMBuildSystem: BuildSystemIntegration.BuiltInBuildSystem {
     }
 
     return SourceKitOptionsResponse(
-      compilerArguments: try await compilerArguments(for: request.textDocument.uri, in: buildTarget),
+      compilerArguments: try await compilerArguments(for: request.textDocument.uri, in: swiftPMTarget),
       workingDirectory: projectRoot.pathString
     )
   }
@@ -635,14 +630,6 @@ extension SwiftPMBuildSystem: BuildSystemIntegration.BuiltInBuildSystem {
     await self.packageLoadingQueue.async {}.valuePropagatingCancellation
   }
 
-  package func topologicalSort(of targets: [BuildTargetIdentifier]) -> [BuildTargetIdentifier]? {
-    return targets.sorted { (lhs: BuildTargetIdentifier, rhs: BuildTargetIdentifier) -> Bool in
-      let lhsDepth = self.targets[lhs]?.depth ?? 0
-      let rhsDepth = self.targets[rhs]?.depth ?? 0
-      return lhsDepth > rhsDepth
-    }
-  }
-
   package func prepare(request: PrepareTargetsRequest) async throws -> VoidResponse {
     // TODO: Support preparation of multiple targets at once. (https://github.com/swiftlang/sourcekit-lsp/issues/1262)
     for target in request.targets {
@@ -804,21 +791,6 @@ extension SwiftPMBuildSystem: BuildSystemIntegration.BuiltInBuildSystem {
     }
   }
 
-  package func sourceFiles() -> [SourceFileInfo] {
-    var sourceFiles: [DocumentURI: SourceFileInfo] = [:]
-    for (buildTarget, depth) in self.targets.values {
-      for sourceFile in buildTarget.sources {
-        let uri = DocumentURI(sourceFile)
-        sourceFiles[uri] = SourceFileInfo(
-          uri: uri,
-          isPartOfRootProject: depth == 1 || (sourceFiles[uri]?.isPartOfRootProject ?? false),
-          mayContainTests: true
-        )
-      }
-    }
-    return sourceFiles.values.sorted { $0.uri.pseudoPath < $1.uri.pseudoPath }
-  }
-
   package func addSourceFilesDidChangeCallback(_ callback: @Sendable @escaping () async -> Void) async {
     testFilesDidChangeCallbacks.append(callback)
   }