Centralize dependency diagnostics in ValidateDependencies action

Instead of emitting diagnostics directly, individual tasks emit .dependencies files which are read by a per-target action which aggregates them. This avoids duplication of diagnostics across tasks.

rdar://156174696

Author: neonichu

Sources/SWBCore/Dependencies.swift

@@ -63,7 +63,7 @@ public struct ModuleDependency: Hashable, Sendable, SerializableCodable {
 }
 
 public struct ModuleDependenciesContext: Sendable, SerializableCodable {
-    var validate: BooleanWarningLevel
+    public var validate: BooleanWarningLevel
     var moduleDependencies: [ModuleDependency]
     var fixItContext: FixItContext?
 
@@ -235,3 +235,34 @@ public struct ModuleDependenciesContext: Sendable, SerializableCodable {
         }
     }
 }
+
+public struct DependencyValidationInfo: Hashable, Sendable, Codable {
+    public struct Import: Hashable, Sendable, Codable {
+        public let dependency: ModuleDependency
+        public let importLocations: [Diagnostic.Location]
+    }
+
+    public enum Payload: Hashable, Sendable, Codable {
+        case clangDependencies(files: [String])
+        case swiftDependencies(imports: [Import])
+        case unsupported
+    }
+
+    public let payload: Payload
+
+    public init(files: [Path]?) {
+        if let files {
+            self.payload = .clangDependencies(files: files.map { $0.str })
+        } else {
+            self.payload = .unsupported
+        }
+    }
+
+    public init(imports: [(ModuleDependency, importLocations: [SWBUtil.Diagnostic.Location])]?) {
+        if let imports {
+            self.payload = .swiftDependencies(imports: imports.map { Import(dependency: $0.0, importLocations: $0.importLocations) })
+        } else {
+            self.payload = .unsupported
+        }
+    }
+}

Sources/SWBCore/PlannedTaskAction.swift

@@ -346,6 +346,7 @@ public protocol TaskActionCreationDelegate
     func createSignatureCollectionTaskAction() -> any PlannedTaskAction
     func createClangModuleVerifierInputGeneratorTaskAction() -> any PlannedTaskAction
     func createProcessSDKImportsTaskAction() -> any PlannedTaskAction
+    func createValidateDependenciesTaskAction() -> any PlannedTaskAction
 }
 
 extension TaskActionCreationDelegate {

Sources/SWBCore/SpecImplementations/RegisterSpecs.swift

@@ -126,6 +126,7 @@ public struct BuiltinSpecsExtension: SpecificationsExtension {
             RegisterExecutionPolicyExceptionToolSpec.self,
             SwiftHeaderToolSpec.self,
             TAPIMergeToolSpec.self,
+            ValidateDependenciesSpec.self,
             ValidateDevelopmentAssets.self,
             ConstructStubExecutorFileListToolSpec.self,
             GateSpec.self,

Sources/SWBCore/SpecImplementations/Tools/CCompiler.swift

@@ -434,8 +434,9 @@ public struct ClangTaskPayload: ClangModuleVerifierPayloadType, DependencyInfoEd
 
     public let moduleDependenciesContext: ModuleDependenciesContext?
     public let traceFilePath: Path?
+    public let dependencyValidationOutputPath: Path?
 
-    fileprivate init(serializedDiagnosticsPath: Path?, indexingPayload: ClangIndexingPayload?, explicitModulesPayload: ClangExplicitModulesPayload? = nil, outputObjectFilePath: Path? = nil, fileNameMapPath: Path? = nil, developerPathString: String? = nil, moduleDependenciesContext: ModuleDependenciesContext? = nil, traceFilePath: Path? = nil) {
+    fileprivate init(serializedDiagnosticsPath: Path?, indexingPayload: ClangIndexingPayload?, explicitModulesPayload: ClangExplicitModulesPayload? = nil, outputObjectFilePath: Path? = nil, fileNameMapPath: Path? = nil, developerPathString: String? = nil, moduleDependenciesContext: ModuleDependenciesContext? = nil, traceFilePath: Path? = nil, dependencyValidationOutputPath: Path? = nil) {
         if let developerPathString, explicitModulesPayload == nil {
             self.dependencyInfoEditPayload = .init(removablePaths: [], removableBasenames: [], developerPath: Path(developerPathString))
         } else {
@@ -448,10 +449,11 @@ public struct ClangTaskPayload: ClangModuleVerifierPayloadType, DependencyInfoEd
         self.fileNameMapPath = fileNameMapPath
         self.moduleDependenciesContext = moduleDependenciesContext
         self.traceFilePath = traceFilePath
+        self.dependencyValidationOutputPath = dependencyValidationOutputPath
     }
 
     public func serialize<T: Serializer>(to serializer: T) {
-        serializer.serializeAggregate(8) {
+        serializer.serializeAggregate(9) {
             serializer.serialize(serializedDiagnosticsPath)
             serializer.serialize(indexingPayload)
             serializer.serialize(explicitModulesPayload)
@@ -460,11 +462,12 @@ public struct ClangTaskPayload: ClangModuleVerifierPayloadType, DependencyInfoEd
             serializer.serialize(dependencyInfoEditPayload)
             serializer.serialize(moduleDependenciesContext)
             serializer.serialize(traceFilePath)
+            serializer.serialize(dependencyValidationOutputPath)
         }
     }
 
     public init(from deserializer: any Deserializer) throws {
-        try deserializer.beginAggregate(8)
+        try deserializer.beginAggregate(9)
         self.serializedDiagnosticsPath = try deserializer.deserialize()
         self.indexingPayload = try deserializer.deserialize()
         self.explicitModulesPayload = try deserializer.deserialize()
@@ -473,6 +476,7 @@ public struct ClangTaskPayload: ClangModuleVerifierPayloadType, DependencyInfoEd
         self.dependencyInfoEditPayload = try deserializer.deserialize()
         self.moduleDependenciesContext = try deserializer.deserialize()
         self.traceFilePath = try deserializer.deserialize()
+        self.dependencyValidationOutputPath = try deserializer.deserialize()
     }
 }
 
@@ -1165,10 +1169,14 @@ public class ClangCompilerSpec : CompilerSpec, SpecIdentifierType, GCCCompatible
             dependencyData = nil
         }
 
+        let extraOutputs: [any PlannedNode]
         let moduleDependenciesContext = cbc.producer.moduleDependenciesContext
+        let dependencyValidationOutputPath: Path?
         let traceFilePath: Path?
         if clangInfo?.hasFeature("print-headers-direct-per-file") ?? false,
             (moduleDependenciesContext?.validate ?? .defaultValue) != .no {
+            dependencyValidationOutputPath = Path(outputNode.path.str + ".dependencies")
+
             let file = Path(outputNode.path.str + ".trace.json")
             commandLine += [
                 "-Xclang", "-header-include-file",
@@ -1177,8 +1185,12 @@ public class ClangCompilerSpec : CompilerSpec, SpecIdentifierType, GCCCompatible
                 "-Xclang", "-header-include-format=json"
             ]
             traceFilePath = file
+
+            extraOutputs = [MakePlannedPathNode(dependencyValidationOutputPath!), MakePlannedPathNode(traceFilePath!)]
         } else {
+            dependencyValidationOutputPath = nil
             traceFilePath = nil
+            extraOutputs = []
         }
 
         // Add the diagnostics serialization flag.  We currently place the diagnostics file right next to the output object file.
@@ -1293,7 +1305,8 @@ public class ClangCompilerSpec : CompilerSpec, SpecIdentifierType, GCCCompatible
             fileNameMapPath: verifierPayload?.fileNameMapPath,
             developerPathString: recordSystemHeaderDepsOutsideSysroot ? cbc.scope.evaluate(BuiltinMacros.DEVELOPER_DIR).str : nil,
             moduleDependenciesContext: moduleDependenciesContext,
-            traceFilePath: traceFilePath
+            traceFilePath: traceFilePath,
+            dependencyValidationOutputPath: dependencyValidationOutputPath
         )
 
         var inputNodes: [any PlannedNode] = inputDeps.map { delegate.createNode($0) }
@@ -1357,7 +1370,7 @@ public class ClangCompilerSpec : CompilerSpec, SpecIdentifierType, GCCCompatible
         }
 
         // Finally, create the task.
-        delegate.createTask(type: self, dependencyData: dependencyData, payload: payload, ruleInfo: ruleInfo, additionalSignatureData: additionalSignatureData, commandLine: commandLine, additionalOutput: additionalOutput, environment: environmentBindings, workingDirectory: compilerWorkingDirectory(cbc), inputs: inputNodes + extraInputs, outputs: [outputNode], action: action ?? delegate.taskActionCreationDelegate.createDeferredExecutionTaskActionIfRequested(userPreferences: cbc.producer.userPreferences), execDescription: resolveExecutionDescription(cbc, delegate), enableSandboxing: enableSandboxing, additionalTaskOrderingOptions: [.compilationForIndexableSourceFile], usesExecutionInputs: usesExecutionInputs, showEnvironment: true, priority: .preferred)
+        delegate.createTask(type: self, dependencyData: dependencyData, payload: payload, ruleInfo: ruleInfo, additionalSignatureData: additionalSignatureData, commandLine: commandLine, additionalOutput: additionalOutput, environment: environmentBindings, workingDirectory: compilerWorkingDirectory(cbc), inputs: inputNodes + extraInputs, outputs: [outputNode] + extraOutputs, action: action ?? delegate.taskActionCreationDelegate.createDeferredExecutionTaskActionIfRequested(userPreferences: cbc.producer.userPreferences), execDescription: resolveExecutionDescription(cbc, delegate), enableSandboxing: enableSandboxing, additionalTaskOrderingOptions: [.compilationForIndexableSourceFile], usesExecutionInputs: usesExecutionInputs, showEnvironment: true, priority: .preferred)
 
         // If the object file verifier is enabled and we are building with explicit modules, also create a job to produce adjacent objects using implicit modules, then compare the results.
         if cbc.scope.evaluate(BuiltinMacros.CLANG_ENABLE_EXPLICIT_MODULES_OBJECT_FILE_VERIFIER) && action != nil {

Sources/SWBCore/SpecImplementations/Tools/SwiftCompiler.swift

@@ -273,6 +273,29 @@ public struct SwiftSourceFileIndexingInfo: SourceFileIndexingInfo {
     }
 }
 
+public struct SwiftDependencyValidationPayload: Serializable, Encodable, Sendable {
+    public let dependencyValidationOutputPath: Path
+    public let moduleDependenciesContext: ModuleDependenciesContext
+
+    public init(dependencyValidationOutputPath: Path, moduleDependenciesContext: ModuleDependenciesContext) {
+        self.dependencyValidationOutputPath = dependencyValidationOutputPath
+        self.moduleDependenciesContext = moduleDependenciesContext
+    }
+
+    public func serialize<T: Serializer>(to serializer: T) {
+        serializer.serializeAggregate(2) {
+            serializer.serialize(dependencyValidationOutputPath)
+            serializer.serialize(moduleDependenciesContext)
+        }
+    }
+
+    public init(from deserializer: any Deserializer) throws {
+        try deserializer.beginAggregate(2)
+        self.dependencyValidationOutputPath = try deserializer.deserialize()
+        self.moduleDependenciesContext = try deserializer.deserialize()
+    }
+}
+
 /// The minimal data we need to serialize to reconstruct `generatePreviewInfo`
 public struct SwiftPreviewPayload: Serializable, Encodable, Sendable {
     public let architecture: String
@@ -446,9 +469,9 @@ public struct SwiftTaskPayload: ParentTaskPayload {
     /// The preview build style in effect (dynamic replacement or XOJIT), if any.
     public let previewStyle: PreviewStyleMessagePayload?
 
-    public let moduleDependenciesContext: ModuleDependenciesContext?
+    public let dependencyValidationPayload: SwiftDependencyValidationPayload?
 
-    init(moduleName: String, indexingPayload: SwiftIndexingPayload, previewPayload: SwiftPreviewPayload?, localizationPayload: SwiftLocalizationPayload?, numExpectedCompileSubtasks: Int, driverPayload: SwiftDriverPayload?, previewStyle: PreviewStyle?, moduleDependenciesContext: ModuleDependenciesContext?) {
+    init(moduleName: String, indexingPayload: SwiftIndexingPayload, previewPayload: SwiftPreviewPayload?, localizationPayload: SwiftLocalizationPayload?, numExpectedCompileSubtasks: Int, driverPayload: SwiftDriverPayload?, previewStyle: PreviewStyle?, dependencyValidationPayload: SwiftDependencyValidationPayload?) {
         self.moduleName = moduleName
         self.indexingPayload = indexingPayload
         self.previewPayload = previewPayload
@@ -463,7 +486,7 @@ public struct SwiftTaskPayload: ParentTaskPayload {
         case nil:
             self.previewStyle = nil
         }
-        self.moduleDependenciesContext = moduleDependenciesContext
+        self.dependencyValidationPayload = dependencyValidationPayload
     }
 
     public func serialize<T: Serializer>(to serializer: T) {
@@ -475,7 +498,7 @@ public struct SwiftTaskPayload: ParentTaskPayload {
             serializer.serialize(numExpectedCompileSubtasks)
             serializer.serialize(driverPayload)
             serializer.serialize(previewStyle)
-            serializer.serialize(moduleDependenciesContext)
+            serializer.serialize(dependencyValidationPayload)
         }
     }
 
@@ -488,7 +511,7 @@ public struct SwiftTaskPayload: ParentTaskPayload {
         self.numExpectedCompileSubtasks = try deserializer.deserialize()
         self.driverPayload = try deserializer.deserialize()
         self.previewStyle = try deserializer.deserialize()
-        self.moduleDependenciesContext = try deserializer.deserialize()
+        self.dependencyValidationPayload = try deserializer.deserialize()
     }
 }
 
@@ -2283,6 +2306,20 @@ public final class SwiftCompilerSpec : CompilerSpec, SpecIdentifierType, SwiftDi
                 moduleOutputPaths.append(moduleWrapOutput)
             }
 
+            let dependencyValidationPayload: SwiftDependencyValidationPayload?
+            if let context = cbc.producer.moduleDependenciesContext, let outputPath = objectOutputPaths.first, context.validate != .no {
+                let primarySwiftBaseName = cbc.scope.evaluate(BuiltinMacros.TARGET_NAME) + compilationMode.moduleBaseNameSuffix + "-primary"
+                let dependencyValidationOutputPath = outputPath.dirname.join(primarySwiftBaseName + ".dependencies")
+                extraOutputPaths.append(dependencyValidationOutputPath)
+
+                dependencyValidationPayload = .init(
+                    dependencyValidationOutputPath: dependencyValidationOutputPath,
+                    moduleDependenciesContext: context
+                )
+            } else {
+                dependencyValidationPayload = nil
+            }
+
             // The rule info.
             //
             // NOTE: If this changes, be sure to update the log parser to extract the variant and arch properly.
@@ -2312,7 +2349,7 @@ public final class SwiftCompilerSpec : CompilerSpec, SpecIdentifierType, SwiftDi
                 numExpectedCompileSubtasks: isUsingWholeModuleOptimization ? 1 : cbc.inputs.count,
                 driverPayload: await driverPayload(uniqueID: String(args.hashValue), scope: cbc.scope, delegate: delegate, compilationMode: compilationMode, isUsingWholeModuleOptimization: isUsingWholeModuleOptimization, args: args, tempDirPath: objectFileDir, explicitModulesTempDirPath: Path(cbc.scope.evaluate(BuiltinMacros.SWIFT_EXPLICIT_MODULES_OUTPUT_PATH)), variant: variant, arch: arch + compilationMode.moduleBaseNameSuffix, commandLine: ["builtin-SwiftDriver", "--"] + args, ruleInfo: ruleInfo(compilationMode.ruleNameIntegratedDriver, targetName), casOptions: casOptions, linkerResponseFilePath: moduleLinkerArgsPath),
                 previewStyle: cbc.scope.previewStyle,
-                moduleDependenciesContext: cbc.producer.moduleDependenciesContext
+                dependencyValidationPayload: dependencyValidationPayload
             )
 
             // Finally, assemble the input and output paths and create the Swift compiler command.

Sources/SWBCore/SpecImplementations/Tools/ValidateDependencies.swift

@@ -0,0 +1,64 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+public import SWBUtil
+import SWBMacro
+
+public final class ValidateDependenciesSpec: CommandLineToolSpec, SpecImplementationType, @unchecked Sendable {
+    public static let identifier = "com.apple.tools.validate-dependencies"
+
+    public static func construct(registry: SpecRegistry, proxy: SpecProxy) -> Spec {
+        return ValidateDependenciesSpec(registry: registry)
+    }
+
+    public init(registry: SpecRegistry) {
+        let proxy = SpecProxy(identifier: Self.identifier, domain: "", path: Path(""), type: Self.self, classType: nil, basedOn: nil, data: ["ExecDescription": PropertyListItem("Validate dependencies")], localizedStrings: nil)
+        super.init(createSpecParser(for: proxy, registry: registry), nil, isGeneric: false)
+    }
+
+    required init(_ parser: SpecParser, _ basedOnSpec: Spec?) {
+        super.init(parser, basedOnSpec, isGeneric: false)
+    }
+
+    override public func constructTasks(_ cbc: CommandBuildContext, _ delegate: any TaskGenerationDelegate) async {
+        fatalError("unexpected direct invocation")
+    }
+
+    public override var payloadType: (any TaskPayload.Type)? { return ValidateDependenciesPayload.self }
+
+    public func createTasks(_ cbc: CommandBuildContext, _ delegate: any TaskGenerationDelegate, dependencyInfos: [PlannedPathNode], payload: ValidateDependenciesPayload) async {
+        guard let configuredTarget = cbc.producer.configuredTarget else {
+            return
+        }
+        let output =  delegate.createVirtualNode("ValidateDependencies \(configuredTarget.guid)")
+        delegate.createTask(type: self, payload: payload, ruleInfo: ["ValidateDependencies"], commandLine: ["builtin-validate-dependencies"] + dependencyInfos.map { $0.path.str }, environment: EnvironmentBindings(), workingDirectory: cbc.producer.defaultWorkingDirectory, inputs: dependencyInfos + cbc.commandOrderingInputs, outputs: [output], action: delegate.taskActionCreationDelegate.createValidateDependenciesTaskAction(), preparesForIndexing: false, enableSandboxing: false)
+    }
+}
+
+public struct ValidateDependenciesPayload: TaskPayload, Sendable {
+    public let moduleDependenciesContext: ModuleDependenciesContext
+
+    public init(moduleDependenciesContext: ModuleDependenciesContext) {
+        self.moduleDependenciesContext = moduleDependenciesContext
+    }
+
+    public func serialize<T: Serializer>(to serializer: T) {
+        serializer.serializeAggregate(1) {
+            serializer.serialize(moduleDependenciesContext)
+        }
+    }
+
+    public init(from deserializer: any Deserializer) throws {
+        try deserializer.beginAggregate(1)
+        self.moduleDependenciesContext = try deserializer.deserialize()
+    }
+}

Sources/SWBCore/TaskGeneration.swift

@@ -189,6 +189,8 @@ public protocol CommandProducer: PlatformBuildContext, SpecLookupContext, Refere
 
     var processSDKImportsSpec: ProcessSDKImportsSpec { get }
 
+    var validateDependenciesSpec: ValidateDependenciesSpec { get }
+
     /// The default working directory to use for a task, if it doesn't have a stronger preference.
     var defaultWorkingDirectory: Path { get }