Remove null byte after home directory on Windows

This works around https://github.com/apple/swift-corelibs-foundation/issues/5041, which caused a null byte to be incorrectly added after the user name's home directory, causing, among others, directory iteration to recurse indefinitely, always adding another level of the user's name.

Author: ahoppen

Package.swift

@@ -31,6 +31,7 @@ let package = Package(
         "SKOptions",
         "SKSupport",
         "SourceKitLSP",
+        "SwiftExtensions",
         "ToolchainRegistry",
         .product(name: "ArgumentParser", package: "swift-argument-parser"),
         .product(name: "SwiftToolsSupport-auto", package: "swift-tools-support-core"),

Sources/Diagnose/DiagnoseCommand.swift

@@ -254,7 +254,9 @@ package struct DiagnoseCommand: AsyncParsableCommand {
     let destinationDir = bundlePath.appendingPathComponent("logs")
     try FileManager.default.createDirectory(at: destinationDir, withIntermediateDirectories: true)
 
-    let logFileDirectoryURL = URL(fileURLWithPath: ("~/.sourcekit-lsp/logs" as NSString).expandingTildeInPath)
+    let logFileDirectoryURL = FileManager.default.sanitizedHomeDirectoryForCurrentUser
+      .appendingPathComponent(".sourcekit-lsp")
+      .appendingPathComponent("logs")
     let enumerator = FileManager.default.enumerator(at: logFileDirectoryURL, includingPropertiesForKeys: nil)
     while let fileUrl = enumerator?.nextObject() as? URL {
       guard fileUrl.lastPathComponent.hasPrefix("sourcekit-lsp") else {

Sources/SKSupport/FileSystem.swift

@@ -11,20 +11,19 @@
 //===----------------------------------------------------------------------===//
 
 import Foundation
+import SwiftExtensions
 
 import struct TSCBasic.AbsolutePath
 
-/// The home directory of the current user (same as returned by Foundation's `NSHomeDirectory` method).
-package var homeDirectoryForCurrentUser: AbsolutePath {
-  try! AbsolutePath(validating: NSHomeDirectory())
-}
-
 extension AbsolutePath {
 
   /// Inititializes an absolute path from a string, expanding a leading `~` to `homeDirectoryForCurrentUser` first.
   package init(expandingTilde path: String) throws {
     if path.first == "~" {
-      try self.init(homeDirectoryForCurrentUser, validating: String(path.dropFirst(2)))
+      try self.init(
+        AbsolutePath(validating: FileManager.default.sanitizedHomeDirectoryForCurrentUser.path),
+        validating: String(path.dropFirst(2))
+      )
     } else {
       try self.init(validating: path)
     }

Sources/SwiftExtensions/CMakeLists.txt

@@ -5,6 +5,7 @@ add_library(SwiftExtensions STATIC
   AsyncUtils.swift
   Collection+Only.swift
   Collection+PartitionIntoBatches.swift
+  FileManager+SanitizedHomeDirectoryOfCurrentUser.swift
   NSLock+WithLock.swift
   PipeAsStringHandler.swift
   ResultExtensions.swift

Sources/SwiftExtensions/FileManager+SanitizedHomeDirectoryOfCurrentUser.swift

@@ -0,0 +1,28 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2019 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
+//
+//===----------------------------------------------------------------------===//
+
+import Foundation
+
+extension FileManager {
+  /// Same as `homeDirectoryForCurrentUser` but works around
+  /// https://github.com/apple/swift-corelibs-foundation/issues/5041, which causes a null byte
+  package var sanitizedHomeDirectoryForCurrentUser: URL {
+    let homeDirectory = FileManager.default.homeDirectoryForCurrentUser
+    #if os(Windows)
+    if homeDirectory.lastPathComponent.hasSuffix("\0") {
+      let newLastPathComponent = String(homeDirectory.lastPathComponent.dropLast())
+      return homeDirectory.deletingLastPathComponent().appendingPathComponent(newLastPathComponent)
+    }
+    #endif
+    return homeDirectory
+  }
+}

Sources/sourcekit-lsp/CMakeLists.txt

@@ -10,6 +10,7 @@ target_link_libraries(sourcekit-lsp PRIVATE
   SKOptions
   SKSupport
   SourceKitLSP
+  SwiftExtensions
   ToolchainRegistry
   ArgumentParser
   TSCBasic)

Sources/sourcekit-lsp/SourceKitLSP.swift

@@ -21,6 +21,7 @@ import SKLogging
 import SKOptions
 import SKSupport
 import SourceKitLSP
+import SwiftExtensions
 import ToolchainRegistry
 
 import struct TSCBasic.AbsolutePath
@@ -238,7 +239,9 @@ struct SourceKitLSP: AsyncParsableCommand {
     var options = SourceKitLSPOptions.merging(
       base: commandLineOptions(),
       override: SourceKitLSPOptions(
-        path: URL(fileURLWithPath: ("~/.sourcekit-lsp/config.json" as NSString).expandingTildeInPath)
+        path: FileManager.default.sanitizedHomeDirectoryForCurrentUser
+          .appendingPathComponent(".sourcekit-lsp")
+          .appendingPathComponent("config.json")
       )
     )
     #if canImport(Darwin)
@@ -282,7 +285,9 @@ struct SourceKitLSP: AsyncParsableCommand {
     let realStdoutHandle = FileHandle(fileDescriptor: realStdout, closeOnDealloc: false)
 
     // Directory should match the directory we are searching for logs in `DiagnoseCommand.addNonDarwinLogs`.
-    let logFileDirectoryURL = URL(fileURLWithPath: ("~/.sourcekit-lsp/logs" as NSString).expandingTildeInPath)
+    let logFileDirectoryURL = FileManager.default.sanitizedHomeDirectoryForCurrentUser
+      .appendingPathComponent(".sourcekit-lsp")
+      .appendingPathComponent("logs")
     await setUpGlobalLogFileHandler(
       logFileDirectory: logFileDirectoryURL,
       logFileMaxBytes: 5_000_000,