Add EmitFrontendCommandLines user default

Sources/SWBBuildService/Messages.swift

@@ -312,7 +312,8 @@ private struct SetSessionUserPreferencesMsg: MessageHandler {
             enableBuildSystemCaching: message.enableBuildSystemCaching,
             activityTextShorteningLevel: message.activityTextShorteningLevel,
             usePerConfigurationBuildLocations: message.usePerConfigurationBuildLocations,
-            allowsExternalToolExecution: message.allowsExternalToolExecution ?? UserPreferences.allowsExternalToolExecutionDefaultValue)
+            allowsExternalToolExecution: message.allowsExternalToolExecution ?? UserPreferences.allowsExternalToolExecutionDefaultValue,
+            emitFrontendCommandLines: message.emitFrontendCommandLines ?? false)
         )
 
         return VoidResponse()

Sources/SWBCore/WorkspaceContext.swift

@@ -109,6 +109,9 @@ public struct UserPreferences: Sendable {
     /// Whether dynamic tasks are allowed to request processes be spawned as external tools.
     public let allowsExternalToolExecution: Bool
 
+    /// Whether the frontend command lines for compiler invocations should be emitted to the build log.
+    public let emitFrontendCommandLines: Bool
+
     public static var allowsExternalToolExecutionDefaultValue: Bool {
         #if RC_PLAYGROUNDS
         return true
@@ -123,7 +126,8 @@ public struct UserPreferences: Sendable {
         enableBuildSystemCaching: UserDefaults.enableBuildSystemCaching,
         activityTextShorteningLevel: UserDefaults.activityTextShorteningLevel,
         usePerConfigurationBuildLocations: UserDefaults.usePerConfigurationBuildLocations,
-        allowsExternalToolExecution: UserDefaults.allowsExternalToolExecution
+        allowsExternalToolExecution: UserDefaults.allowsExternalToolExecution,
+        emitFrontendCommandLines: UserDefaults.emitFrontendCommandLines
     )
 
     public init(
@@ -132,14 +136,16 @@ public struct UserPreferences: Sendable {
         enableBuildSystemCaching: Bool,
         activityTextShorteningLevel: ActivityTextShorteningLevel,
         usePerConfigurationBuildLocations: Bool?,
-        allowsExternalToolExecution: Bool
+        allowsExternalToolExecution: Bool,
+        emitFrontendCommandLines: Bool
     ) {
         self.enableDebugActivityLogs = enableDebugActivityLogs
         self.enableBuildDebugging = enableBuildDebugging
         self.enableBuildSystemCaching = enableBuildSystemCaching
         self.activityTextShorteningLevel = activityTextShorteningLevel
         self.usePerConfigurationBuildLocations = usePerConfigurationBuildLocations
         self.allowsExternalToolExecution = allowsExternalToolExecution
+        self.emitFrontendCommandLines = emitFrontendCommandLines
     }
 }
 

Sources/SWBProtocol/Message.swift

@@ -656,6 +656,7 @@ public struct SetSessionUserPreferencesRequest: SessionMessage, RequestMessage,
     public let activityTextShorteningLevel: ActivityTextShorteningLevel
     public let usePerConfigurationBuildLocations: Bool?
     public let allowsExternalToolExecution: Bool?
+    public let emitFrontendCommandLines: Bool?
 
     public init(sessionHandle: String, enableDebugActivityLogs: Bool, enableBuildDebugging: Bool, enableBuildSystemCaching: Bool, activityTextShorteningLevel: ActivityTextShorteningLevel, usePerConfigurationBuildLocations: Bool?) {
         self.sessionHandle = sessionHandle
@@ -665,16 +666,18 @@ public struct SetSessionUserPreferencesRequest: SessionMessage, RequestMessage,
         self.activityTextShorteningLevel = activityTextShorteningLevel
         self.usePerConfigurationBuildLocations = usePerConfigurationBuildLocations
         self.allowsExternalToolExecution = nil
+        self.emitFrontendCommandLines = nil
     }
 
-    public init(sessionHandle: String, enableDebugActivityLogs: Bool, enableBuildDebugging: Bool, enableBuildSystemCaching: Bool, activityTextShorteningLevel: ActivityTextShorteningLevel, usePerConfigurationBuildLocations: Bool?, allowsExternalToolExecution: Bool) {
+    public init(sessionHandle: String, enableDebugActivityLogs: Bool, enableBuildDebugging: Bool, enableBuildSystemCaching: Bool, activityTextShorteningLevel: ActivityTextShorteningLevel, usePerConfigurationBuildLocations: Bool?, allowsExternalToolExecution: Bool, emitFrontendCommandLines: Bool? = nil) {
         self.sessionHandle = sessionHandle
         self.enableDebugActivityLogs = enableDebugActivityLogs
         self.enableBuildDebugging = enableBuildDebugging
         self.enableBuildSystemCaching = enableBuildSystemCaching
         self.activityTextShorteningLevel = activityTextShorteningLevel
         self.usePerConfigurationBuildLocations = usePerConfigurationBuildLocations
         self.allowsExternalToolExecution = allowsExternalToolExecution
+        self.emitFrontendCommandLines = emitFrontendCommandLines
     }
 }
 

Sources/SWBTaskConstruction/ProductPlanning/BuildPlan.swift

@@ -287,7 +287,7 @@ package final class BuildPlan: StaleFileRemovalContext {
         self.invalidationPaths = Array(invalidationPaths.sorted(by: \.str))
         self.recursiveSearchPathResults = globalProductPlan.recursiveSearchPathResolver.allResults
         self.copiedPathMap = copiedPathMap
-        self.emitFrontendCommandLines = productPlanResultContexts.map { $0.productPlan.taskProducerContext.emitFrontendCommandLines }.reduce(false, { $0 || $1 })
+        self.emitFrontendCommandLines = planRequest.workspaceContext.userPreferences.emitFrontendCommandLines || productPlanResultContexts.map { $0.productPlan.taskProducerContext.emitFrontendCommandLines }.reduce(false, { $0 || $1 })
     }
 
     static func unexpectedDuplicateTasksWithIdentifier(_ tasks: [any PlannedTask], _ workspace: Workspace, _ delegate: any TaskPlanningDelegate) {

Sources/SWBTestSupport/TestWorkspaces.swift

@@ -1599,15 +1599,17 @@ extension UserPreferences {
         enableBuildSystemCaching: true,
         activityTextShorteningLevel: .default,
         usePerConfigurationBuildLocations: nil,
-        allowsExternalToolExecution: false)
+        allowsExternalToolExecution: false,
+        emitFrontendCommandLines: false)
 
     package func with(
         enableDebugActivityLogs: Bool? = nil,
         enableBuildDebugging: Bool? = nil,
         enableBuildSystemCaching: Bool? = nil,
         activityTextShorteningLevel: ActivityTextShorteningLevel? = nil,
         usePerConfigurationBuildLocations: Bool?? = .none,
-        allowsExternalToolExecution: Bool? = nil
+        allowsExternalToolExecution: Bool? = nil,
+        emitFrontendCommandLines: Bool? = nil
     ) -> UserPreferences {
         let usePerConfigurationBuildLocationsValue: Bool?
         switch usePerConfigurationBuildLocations {
@@ -1625,7 +1627,8 @@ extension UserPreferences {
             enableBuildSystemCaching: enableBuildSystemCaching ?? self.enableBuildSystemCaching,
             activityTextShorteningLevel: activityTextShorteningLevel ?? self.activityTextShorteningLevel,
             usePerConfigurationBuildLocations: usePerConfigurationBuildLocationsValue,
-            allowsExternalToolExecution: allowsExternalToolExecution ?? self.allowsExternalToolExecution
+            allowsExternalToolExecution: allowsExternalToolExecution ?? self.allowsExternalToolExecution,
+            emitFrontendCommandLines: emitFrontendCommandLines ?? self.emitFrontendCommandLines
         )
     }
 }

Sources/SWBUtil/UserDefaults.swift

@@ -253,6 +253,11 @@ public enum UserDefaults: Sendable {
         return string(forKey: "CompilationCachingDiskSizeLimit")
     }
 
+    /// Whether the frontend command lines for compiler invocations should be emitted to the build log.
+    public static var emitFrontendCommandLines: Bool {
+        return bool(forKey: "EmitFrontendCommandLines")
+    }
+
     /// Provides the default level of QoS support within Swift Build for global queues that are not tied to specific build requests.
     public static var undeterminedQoS: SWBQoS {
         // With 'unspecified' the QoS of the caller is influencing the QoS to be used for the enqueued work item.

Sources/SwiftBuild/SWBBuildServiceSession.swift

@@ -662,10 +662,15 @@ public final class SWBBuildServiceSession: Sendable {
         _ = try await service.send(request: SetSessionUserPreferencesRequest(sessionHandle: self.uid, enableDebugActivityLogs: enableDebugActivityLogs, enableBuildDebugging: enableBuildDebugging, enableBuildSystemCaching: enableBuildSystemCaching, activityTextShorteningLevel: ActivityTextShorteningLevel(rawValue: activityTextShorteningLevel) ?? .default, usePerConfigurationBuildLocations: usePerConfigurationBuildLocations))
     }
 
+    @available(*, deprecated, renamed: "setUserPreferences(enableDebugActivityLogs:enableBuildDebugging:enableBuildSystemCaching:activityTextShorteningLevel:usePerConfigurationBuildLocations:allowsExternalToolExecution:emitFrontendCommandLines:)")
     public func setUserPreferences(enableDebugActivityLogs: Bool, enableBuildDebugging: Bool, enableBuildSystemCaching: Bool, activityTextShorteningLevel: Int, usePerConfigurationBuildLocations: Bool?, allowsExternalToolExecution: Bool) async throws {
         _ = try await service.send(request: SetSessionUserPreferencesRequest(sessionHandle: self.uid, enableDebugActivityLogs: enableDebugActivityLogs, enableBuildDebugging: enableBuildDebugging, enableBuildSystemCaching: enableBuildSystemCaching, activityTextShorteningLevel: ActivityTextShorteningLevel(rawValue: activityTextShorteningLevel) ?? .default, usePerConfigurationBuildLocations: usePerConfigurationBuildLocations, allowsExternalToolExecution: allowsExternalToolExecution))
     }
 
+    public func setUserPreferences(enableDebugActivityLogs: Bool, enableBuildDebugging: Bool, enableBuildSystemCaching: Bool, activityTextShorteningLevel: Int, usePerConfigurationBuildLocations: Bool?, allowsExternalToolExecution: Bool, emitFrontendCommandLines: Bool) async throws {
+        _ = try await service.send(request: SetSessionUserPreferencesRequest(sessionHandle: self.uid, enableDebugActivityLogs: enableDebugActivityLogs, enableBuildDebugging: enableBuildDebugging, enableBuildSystemCaching: enableBuildSystemCaching, activityTextShorteningLevel: ActivityTextShorteningLevel(rawValue: activityTextShorteningLevel) ?? .default, usePerConfigurationBuildLocations: usePerConfigurationBuildLocations, allowsExternalToolExecution: allowsExternalToolExecution, emitFrontendCommandLines: emitFrontendCommandLines))
+    }
+
     public func lookupToolchain(at path: String) async throws -> SWBToolchainIdentifier? {
         return try await service.send(request: LookupToolchainRequest(sessionHandle: self.uid, path: Path(path))).toolchainIdentifier.map { SWBToolchainIdentifier(rawValue: $0) }
     }

Sources/SwiftBuildTestSupport/TestUtilities.swift

@@ -216,7 +216,8 @@ extension SWBBuildServiceSession {
             enableBuildSystemCaching: userPreferences.enableBuildSystemCaching,
             activityTextShorteningLevel: userPreferences.activityTextShorteningLevel.rawValue,
             usePerConfigurationBuildLocations: userPreferences.usePerConfigurationBuildLocations,
-            allowsExternalToolExecution: userPreferences.allowsExternalToolExecution)
+            allowsExternalToolExecution: userPreferences.allowsExternalToolExecution,
+            emitFrontendCommandLines: userPreferences.emitFrontendCommandLines)
     }
 
     package func generateIndexingFileSettings(for request: SWBBuildRequest, targetID: String, delegate: any SWBIndexingDelegate) async throws -> SWBIndexingFileSettings {

SwiftBuild.docc/Development/build-debugging.md

@@ -15,6 +15,14 @@ defaults write org.swift.swift-build EnableDebugActivityLogs -bool YES
 This will cause Swift Build to emit more detailed note diagnostics to the build log
 which is deemed to verbose for normal usage.
 
+### Frontend command lines
+
+```
+defaults write org.swift.swift-build EmitFrontendCommandLines -bool YES
+```
+
+This will cause Swift Build to emit the frontend command lines for compiler invocations to the build log. It is a lighter-weight subset of `EnableDebugActivityLogs` equivalent to setting the `EMIT_FRONTEND_COMMAND_LINES` build setting persistently.
+
 ### Incremental build debugging
 
 ```

Tests/SWBBuildSystemTests/BuildOperationTests.swift

@@ -8120,6 +8120,40 @@ That command depends on command in Target 'agg2' (project \'aProject\'): script
         }
     }
 
+    @Test(.requireSDKs(.macOS), arguments: [true, false])
+    func emitFrontendCommandLines(preference: Bool) async throws {
+        // Each parameterized invocation is independent, giving the BuildDescriptionManager
+        // a fresh workspace so it plans with the correct emitFrontendCommandLines value.
+        try await withTemporaryDirectory { tmpDirPath in
+            let testWorkspace = try await TestWorkspace(
+                "Test",
+                sourceRoot: tmpDirPath.join("Test"),
+                projects: [
+                    TestProject(
+                        "aProject",
+                        groupTree: TestGroup("Sources", path: "Sources", children: [TestFile("Source.swift")]),
+                        buildConfigurations: [TestBuildConfiguration("Debug", buildSettings: [
+                            "PRODUCT_NAME": "$(TARGET_NAME)",
+                            "SWIFT_VERSION": swiftVersion,
+                            "SWIFT_USE_INTEGRATED_DRIVER": "YES",
+                        ])],
+                        targets: [TestStandardTarget("TargetA", type: .framework, buildPhases: [TestSourcesBuildPhase(["Source.swift"])])])
+                ])
+            let tester = try await BuildOperationTester(getCore(), testWorkspace, simulated: false)
+            let SRCROOT = testWorkspace.sourceRoot.join("aProject")
+            try await tester.fs.writeFileContents(SRCROOT.join("Sources/Source.swift")) { $0 <<< "struct A {}\n" }
+            tester.userPreferences = .defaultForTesting.with(emitFrontendCommandLines: preference)
+            try await tester.checkBuild(runDestination: .macOS, persistent: true) { results in
+                results.checkNoErrors()
+                results.checkTask(.matchRuleType("SwiftCompile")) { task in
+                    results.checkTaskOutput(task) { output in
+                        #expect(output.stringValue?.contains("swift-frontend") == preference)
+                    }
+                }
+            }
+        }
+    }
+
     @Test(.requireSDKs(.host))
     func swiftSDKToolsets() async throws {
         try await withTemporaryDirectory { tmpDirPath async throws -> Void in

Tests/SWBCoreTests/SettingsTests.swift

@@ -5715,4 +5715,5 @@ import SWBTestSupport
             }
         }
     }
+
 }

Tests/SWBProtocolTests/MessageSerializationTests.swift

@@ -77,6 +77,8 @@ import Testing
         assertMsgPackMessageRoundTrip(SetSessionSystemInfoRequest(sessionHandle: "theSession", operatingSystemVersion: Version(11, 1, 3), productBuildVersion: "25A573", nativeArchitecture: "arm64"))
         assertMsgPackMessageRoundTrip(SetSessionUserInfoRequest(sessionHandle: "theSession", user: "mobile", group: "mobile", uid: 501, gid: 99, home: "/root", processEnvironment: ["HOME": "/root"], buildSystemEnvironment: ["SRCROOT": "/"]))
         assertMsgPackMessageRoundTrip(SetSessionUserPreferencesRequest(sessionHandle: "theSession", enableDebugActivityLogs: true, enableBuildDebugging: true, enableBuildSystemCaching: true, activityTextShorteningLevel: .default, usePerConfigurationBuildLocations: nil))
+        assertMsgPackMessageRoundTrip(SetSessionUserPreferencesRequest(sessionHandle: "theSession", enableDebugActivityLogs: true, enableBuildDebugging: true, enableBuildSystemCaching: true, activityTextShorteningLevel: .default, usePerConfigurationBuildLocations: nil, allowsExternalToolExecution: true))
+        assertMsgPackMessageRoundTrip(SetSessionUserPreferencesRequest(sessionHandle: "theSession", enableDebugActivityLogs: true, enableBuildDebugging: true, enableBuildSystemCaching: true, activityTextShorteningLevel: .default, usePerConfigurationBuildLocations: nil, allowsExternalToolExecution: true, emitFrontendCommandLines: true))
         assertMsgPackMessageRoundTrip(ListSessionsRequest())
         assertMsgPackMessageRoundTrip(ListSessionsResponse(sessions: ["theSession": .init(name: "itsGreat", activeBuildCount: 0, activeNormalBuildCount: 0, activeIndexBuildCount: 0)]))
         assertMsgPackMessageRoundTrip(DeleteSessionRequest(sessionHandle: "theSession"))