Fix Windows build failure

Windows has `ProcessResult.ExitStatus.abnormal` instead of ` `ProcessResult.ExitStatus.signalled`

Author: ahoppen

Sources/SKSupport/CMakeLists.txt

@@ -14,6 +14,7 @@ add_library(SKSupport STATIC
   Process+WaitUntilExitWithCancellation.swift
   Random.swift
   Result.swift
+  SwitchableProcessResultExitStatus.swift
   ThreadSafeBox.swift
   WorkspaceType.swift
 )

Sources/SKSupport/SwitchableProcessResultExitStatus.swift

@@ -0,0 +1,45 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+// We need to import all of TSCBasic because otherwise we can't refer to Process.ExitStatus (rdar://127577691)
+import struct TSCBasic.ProcessResult
+
+/// Same as `ProcessResult.ExitStatus` in tools-support-core but has the same cases on all platforms and is thus easier
+/// to switch over
+public enum SwitchableProcessResultExitStatus {
+  /// The process was terminated normally with a exit code.
+  case terminated(code: Int32)
+  /// The process was terminated abnormally.
+  case abnormal(exception: UInt32)
+  /// The process was terminated due to a signal.
+  case signalled(signal: Int32)
+}
+
+extension ProcessResult.ExitStatus {
+  public var exhaustivelySwitchable: SwitchableProcessResultExitStatus {
+    #if os(Windows)
+    switch self {
+    case .terminated(let code):
+      return .terminated(code: code)
+    case .abnormal(let exception):
+      return .abnormal(exception: exception)
+    }
+    #else
+    switch self {
+    case .terminated(let code):
+      return .terminated(code: code)
+    case .signalled(let signal):
+      return .signalled(signal: signal)
+    }
+    #endif
+  }
+}

Sources/SemanticIndex/UpdateIndexStoreTaskDescription.swift

@@ -15,6 +15,7 @@ import Foundation
 import LSPLogging
 import LanguageServerProtocol
 import SKCore
+import SKSupport
 
 import struct TSCBasic.AbsolutePath
 import class TSCBasic.Process
@@ -198,7 +199,7 @@ public struct UpdateIndexStoreTaskDescription: TaskDescriptionProtocol {
       }
     try process.launch()
     let result = try await process.waitUntilExitSendingSigIntOnTaskCancellation()
-    switch result.exitStatus {
+    switch result.exitStatus.exhaustivelySwitchable {
     case .terminated(code: 0):
       break
     case .terminated(code: let code):
@@ -224,6 +225,11 @@ public struct UpdateIndexStoreTaskDescription: TaskDescriptionProtocol {
         logger.error("Updating index store for Swift file \(uri.forLogging) signaled \(signal)")
         BuildSettingsLogger.log(level: .error, settings: buildSettings, for: uri)
       }
+    case .abnormal(exception: let exception):
+      if !Task.isCancelled {
+        logger.error("Updating index store for Swift file \(uri.forLogging) exited abnormally \(exception)")
+        BuildSettingsLogger.log(level: .error, settings: buildSettings, for: uri)
+      }
     }
   }
 }