Make the default logger subsystem configurable

Author: owenv

Package.swift

@@ -72,6 +72,7 @@ var targets: [Target] = [
     name: "LanguageServerProtocolTests",
     dependencies: [
       "LanguageServerProtocol",
+      "SKLogging",
       "ToolsProtocolsTestSupport",
     ],
     swiftSettings: globalSwiftSettings
@@ -95,6 +96,7 @@ var targets: [Target] = [
     name: "LanguageServerProtocolTransportTests",
     dependencies: [
       "LanguageServerProtocolTransport",
+      "SKLogging",
       "ToolsProtocolsTestSupport",
     ],
     swiftSettings: globalSwiftSettings
@@ -119,7 +121,6 @@ var targets: [Target] = [
     ],
     exclude: ["CMakeLists.txt"],
     swiftSettings: globalSwiftSettings + lspLoggingSwiftSettings + [
-      .define("SKLOGGING_FOR_PLUGIN"),
       .unsafeFlags([
         "-module-alias", "SwiftExtensions=_SwiftExtensionsForPlugin",
       ]),

Sources/SKLogging/LoggingScope.swift

@@ -11,8 +11,13 @@
 //===----------------------------------------------------------------------===//
 
 import Foundation
+@_spi(SourceKitLSP) import SwiftExtensions
+
+public final class LoggingScope {
+
+  /// The name of the default logging subsystem if no task-local value is set.
+  fileprivate static let defaultSubsystem: ThreadSafeBox<String?> = .init(initialValue: nil)
 
-@_spi(SourceKitLSP) public final class LoggingScope {
   /// The name of the current logging subsystem or `nil` if no logging scope is set.
   @TaskLocal fileprivate static var _subsystem: String?
 
@@ -21,17 +26,23 @@ import Foundation
 
   /// The name of the current logging subsystem.
   @_spi(SourceKitLSP) public static var subsystem: String {
-    #if SKLOGGING_FOR_PLUGIN
-    return _subsystem ?? "org.swift.sourcekit-lsp.plugin"
-    #else
-    return _subsystem ?? "org.swift.sourcekit-lsp"
-    #endif
+    if let _subsystem {
+      return _subsystem
+    } else if let defaultSubsystem = defaultSubsystem.value {
+      return defaultSubsystem
+    } else {
+      fatalError("SKLogging: default subsystem was not configured before first use")
+    }
   }
 
   /// The name of the current logging scope.
   @_spi(SourceKitLSP) public static var scope: String {
     return _scope ?? "default"
   }
+
+  public static func configureDefaultLoggingSubsystem(_ subsystem: String) {
+    LoggingScope.defaultSubsystem.withLock { $0 = subsystem }
+  }
 }
 
 /// Logs all messages created from the operation to the given subsystem.

Tests/LanguageServerProtocolTests/ConnectionTests.swift

@@ -12,13 +12,15 @@
 
 import LanguageServerProtocol
 import ToolsProtocolsTestSupport
+import SKLogging
 import XCTest
 
 class ConnectionTests: XCTestCase {
 
   var connection: TestLocalConnection! = nil
 
   override func setUp() {
+    LoggingScope.configureDefaultLoggingSubsystem("org.swift.swift-tools-protocols-tests")
     connection = TestLocalConnection(allowUnexpectedNotification: false)
   }
 

Tests/LanguageServerProtocolTransportTests/ConnectionPerfTests.swift

@@ -12,13 +12,15 @@
 
 import LanguageServerProtocolTransport
 import ToolsProtocolsTestSupport
+import SKLogging
 import XCTest
 
 class ConnectionPerfTests: PerfTestCase {
 
   var connection: TestJSONRPCConnection! = nil
 
   override func setUp() {
+    LoggingScope.configureDefaultLoggingSubsystem("org.swift.swift-tools-protocols-tests")
     connection = TestJSONRPCConnection()
   }
 

Tests/SKLoggingTests/LoggingTests.swift

@@ -70,6 +70,11 @@ private func assertLogging(
 }
 
 final class LoggingTests: XCTestCase {
+
+  override func setUp() async throws {
+    LoggingScope.configureDefaultLoggingSubsystem("org.swift.swift-tools-protocols-tests")
+  }
+
   func testLoggingFormat() async throws {
     let expectation = self.expectation(description: "message logged")
     // nonisolated(unsafe) because we only have a single call to `logger.log` and that cannot race.
@@ -85,7 +90,7 @@ final class LoggingTests: XCTestCase {
     logger.log(level: .error, "my message")
     try await fulfillmentOfOrThrow(expectation)
     XCTAssert(
-      message.starts(with: "[org.swift.sourcekit-lsp:test] error"),
+      message.starts(with: "[org.swift.swift-tools-protocols-tests:test] error"),
       "Message did not have expected header. Received \n\(message)"
     )
     XCTAssert(message.hasSuffix("\nmy message\n---"), "Message did not have expected body. Received \n\(message)")

Tests/SwiftExtensionsTests/AsyncUtilsTests.swift

@@ -22,6 +22,10 @@ import Android
 #endif
 
 final class AsyncUtilsTests: XCTestCase {
+  override func setUp() async throws {
+    LoggingScope.configureDefaultLoggingSubsystem("org.swift.swift-tools-protocols-tests")
+  }
+
   func testWithTimeout() async throws {
     let expectation = self.expectation(description: "withTimeout body finished")
     await assertThrowsError(