Enforce use of throwing AbsolutePath initializer (#353)

In support of swiftlang/swift-package-manager#5797

Author: neonichu

Sources/TSCBasic/FileSystem.swift

@@ -187,13 +187,13 @@ public protocol FileSystem: AnyObject {
     func changeCurrentWorkingDirectory(to path: AbsolutePath) throws
 
     /// Get the home directory of current user
-    var homeDirectory: AbsolutePath { get }
+    var homeDirectory: AbsolutePath { get throws }
 
     /// Get the caches directory of current user
     var cachesDirectory: AbsolutePath? { get }
 
     /// Get the temp directory
-    var tempDirectory: AbsolutePath { get }
+    var tempDirectory: AbsolutePath { get throws }
 
     /// Create the given directory.
     func createDirectory(_ path: AbsolutePath) throws
@@ -317,7 +317,9 @@ private class LocalFileSystem: FileSystem {
     }
 
     func isFile(_ path: AbsolutePath) -> Bool {
-        let path = resolveSymlinks(path)
+        guard let path = try? resolveSymlinks(path) else {
+            return false
+        }
         let attrs = try? FileManager.default.attributesOfItem(atPath: path.pathString)
         return attrs?[.type] as? FileAttributeType == .typeRegular
     }
@@ -353,7 +355,7 @@ private class LocalFileSystem: FileSystem {
         let fsr: UnsafePointer<Int8> = cwdStr.fileSystemRepresentation
         defer { fsr.deallocate() }
 
-        return try? AbsolutePath(validating: String(cString: fsr))
+        return try? AbsolutePath(String(cString: fsr))
 #endif
     }
 
@@ -368,19 +370,23 @@ private class LocalFileSystem: FileSystem {
     }
 
     var homeDirectory: AbsolutePath {
-        return AbsolutePath(NSHomeDirectory())
+        get throws {
+            return try AbsolutePath(validating: NSHomeDirectory())
+        }
     }
 
     var cachesDirectory: AbsolutePath? {
-        return FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first.flatMap { AbsolutePath($0.path) }
+        return FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first.flatMap { try? AbsolutePath(validating: $0.path) }
     }
 
     var tempDirectory: AbsolutePath {
-        let override = ProcessEnv.vars["TMPDIR"] ?? ProcessEnv.vars["TEMP"] ?? ProcessEnv.vars["TMP"]
-        if let path = override.flatMap({ try? AbsolutePath(validating: $0) }) {
-            return path
+        get throws {
+            let override = ProcessEnv.vars["TMPDIR"] ?? ProcessEnv.vars["TEMP"] ?? ProcessEnv.vars["TMP"]
+            if let path = override.flatMap({ try? AbsolutePath(validating: $0) }) {
+                return path
+            }
+            return try AbsolutePath(validating: NSTemporaryDirectory())
         }
-        return AbsolutePath(NSTemporaryDirectory())
     }
 
     func getDirectoryContents(_ path: AbsolutePath) throws -> [String] {
@@ -664,7 +670,7 @@ public class InMemoryFileSystem: FileSystem {
             case .directory, .file:
                 return node
             case .symlink(let destination):
-                let destination = AbsolutePath(destination, relativeTo: path.parentDirectory)
+                let destination = try AbsolutePath(validating: destination, relativeTo: path.parentDirectory)
                 return followSymlink ? try getNodeInternal(destination) : node
             case .none:
                 return nil
@@ -745,24 +751,28 @@ public class InMemoryFileSystem: FileSystem {
 
     /// Virtualized current working directory.
     public var currentWorkingDirectory: AbsolutePath? {
-        return AbsolutePath("/")
+        return try? AbsolutePath(validating: "/")
     }
 
     public func changeCurrentWorkingDirectory(to path: AbsolutePath) throws {
         throw FileSystemError(.unsupported, path)
     }
 
     public var homeDirectory: AbsolutePath {
-        // FIXME: Maybe we should allow setting this when creating the fs.
-        return AbsolutePath("/home/user")
+        get throws {
+            // FIXME: Maybe we should allow setting this when creating the fs.
+            return try AbsolutePath(validating: "/home/user")
+        }
     }
 
     public var cachesDirectory: AbsolutePath? {
-        return self.homeDirectory.appending(component: "caches")
+        return try? self.homeDirectory.appending(component: "caches")
     }
 
     public var tempDirectory: AbsolutePath {
-        return AbsolutePath("/tmp")
+        get throws {
+            return try AbsolutePath(validating: "/tmp")
+        }
     }
 
     public func getDirectoryContents(_ path: AbsolutePath) throws -> [String] {
@@ -978,7 +988,7 @@ public class InMemoryFileSystem: FileSystem {
     public func withLock<T>(on path: AbsolutePath, type: FileLock.LockType = .exclusive, _ body: () throws -> T) throws -> T {
         let resolvedPath: AbsolutePath = try lock.withLock {
             if case let .symlink(destination) = try getNode(path)?.contents {
-                return AbsolutePath(destination, relativeTo: path.parentDirectory)
+                return try AbsolutePath(validating: destination, relativeTo: path.parentDirectory)
             } else {
                 return path
             }
@@ -1023,48 +1033,69 @@ public class RerootedFileSystemView: FileSystem {
     }
 
     /// Adjust the input path for the underlying file system.
-    private func formUnderlyingPath(_ path: AbsolutePath) -> AbsolutePath {
+    private func formUnderlyingPath(_ path: AbsolutePath) throws -> AbsolutePath {
         if path == AbsolutePath.root {
             return root
         } else {
             // FIXME: Optimize?
-            return AbsolutePath(String(path.pathString.dropFirst(1)), relativeTo: root)
+            return try AbsolutePath(validating: String(path.pathString.dropFirst(1)), relativeTo: root)
         }
     }
 
     // MARK: FileSystem Implementation
 
     public func exists(_ path: AbsolutePath, followSymlink: Bool) -> Bool {
-        return underlyingFileSystem.exists(formUnderlyingPath(path), followSymlink: followSymlink)
+        guard let underlying = try? formUnderlyingPath(path) else {
+            return false
+        }
+        return underlyingFileSystem.exists(underlying, followSymlink: followSymlink)
     }
 
     public func isDirectory(_ path: AbsolutePath) -> Bool {
-        return underlyingFileSystem.isDirectory(formUnderlyingPath(path))
+        guard let underlying = try? formUnderlyingPath(path) else {
+            return false
+        }
+        return underlyingFileSystem.isDirectory(underlying)
     }
 
     public func isFile(_ path: AbsolutePath) -> Bool {
-        return underlyingFileSystem.isFile(formUnderlyingPath(path))
+        guard let underlying = try? formUnderlyingPath(path) else {
+            return false
+        }
+        return underlyingFileSystem.isFile(underlying)
     }
 
     public func isSymlink(_ path: AbsolutePath) -> Bool {
-        return underlyingFileSystem.isSymlink(formUnderlyingPath(path))
+        guard let underlying = try? formUnderlyingPath(path) else {
+            return false
+        }
+        return underlyingFileSystem.isSymlink(underlying)
     }
 
     public func isReadable(_ path: AbsolutePath) -> Bool {
-        return underlyingFileSystem.isReadable(formUnderlyingPath(path))
+        guard let underlying = try? formUnderlyingPath(path) else {
+            return false
+        }
+        return underlyingFileSystem.isReadable(underlying)
     }
 
     public func isWritable(_ path: AbsolutePath) -> Bool {
-        return underlyingFileSystem.isWritable(formUnderlyingPath(path))
+        guard let underlying = try? formUnderlyingPath(path) else {
+            return false
+        }
+        return underlyingFileSystem.isWritable(underlying)
     }
 
     public func isExecutableFile(_ path: AbsolutePath) -> Bool {
-        return underlyingFileSystem.isExecutableFile(formUnderlyingPath(path))
+        guard let underlying = try? formUnderlyingPath(path) else {
+            return false
+        }
+        return underlyingFileSystem.isExecutableFile(underlying)
     }
 
     /// Virtualized current working directory.
     public var currentWorkingDirectory: AbsolutePath? {
-        return AbsolutePath("/")
+        return try? AbsolutePath(validating: "/")
     }
 
     public func changeCurrentWorkingDirectory(to path: AbsolutePath) throws {
@@ -1088,13 +1119,13 @@ public class RerootedFileSystemView: FileSystem {
     }
 
     public func createDirectory(_ path: AbsolutePath, recursive: Bool) throws {
-        let path = formUnderlyingPath(path)
+        let path = try formUnderlyingPath(path)
         return try underlyingFileSystem.createDirectory(path, recursive: recursive)
     }
 
     public func createSymbolicLink(_ path: AbsolutePath, pointingAt destination: AbsolutePath, relative: Bool) throws {
-        let path = formUnderlyingPath(path)
-        let destination = formUnderlyingPath(destination)
+        let path = try formUnderlyingPath(path)
+        let destination = try formUnderlyingPath(destination)
         return try underlyingFileSystem.createSymbolicLink(path, pointingAt: destination, relative: relative)
     }
 
@@ -1103,7 +1134,7 @@ public class RerootedFileSystemView: FileSystem {
     }
 
     public func writeFileContents(_ path: AbsolutePath, bytes: ByteString) throws {
-        let path = formUnderlyingPath(path)
+        let path = try formUnderlyingPath(path)
         return try underlyingFileSystem.writeFileContents(path, bytes: bytes)
     }
 

Sources/TSCBasic/Lock.swift

@@ -180,15 +180,15 @@ public final class FileLock {
 
     public static func withLock<T>(fileToLock: AbsolutePath, lockFilesDirectory: AbsolutePath? = nil, type: LockType = .exclusive, body: () throws -> T) throws -> T {
         // unless specified, we use the tempDirectory to store lock files
-        let lockFilesDirectory = lockFilesDirectory ?? localFileSystem.tempDirectory
+        let lockFilesDirectory = try lockFilesDirectory ?? localFileSystem.tempDirectory
         if !localFileSystem.exists(lockFilesDirectory) {
             throw FileSystemError(.noEntry, lockFilesDirectory)
         }
         if !localFileSystem.isDirectory(lockFilesDirectory) {
             throw FileSystemError(.notDirectory, lockFilesDirectory)
         }
         // use the parent path to generate unique filename in temp
-        var lockFileName = (resolveSymlinks(fileToLock.parentDirectory)
+        var lockFileName = try (resolveSymlinks(fileToLock.parentDirectory)
                                 .appending(component: fileToLock.basename))
                                 .components.joined(separator: "_")
                                 .replacingOccurrences(of: ":", with: "_") + ".lock"

Sources/TSCBasic/Path.swift

@@ -59,21 +59,12 @@ public struct AbsolutePath: Hashable {
         _impl = impl
     }
 
-    /// Initializes the AbsolutePath from `absStr`, which must be an absolute
-    /// path (i.e. it must begin with a path separator; this initializer does
-    /// not interpret leading `~` characters as home directory specifiers).
-    /// The input string will be normalized if needed, as described in the
-    /// documentation for AbsolutePath.
-    public init(_ absStr: String) {
-        self.init(PathImpl(normalizingAbsolutePath: absStr))
-    }
-
     /// Initializes an AbsolutePath from a string that may be either absolute
     /// or relative; if relative, `basePath` is used as the anchor; if absolute,
     /// it is used as is, and in this case `basePath` is ignored.
-    public init(_ str: String, relativeTo basePath: AbsolutePath) {
+    public init(validating str: String, relativeTo basePath: AbsolutePath) throws {
         if PathImpl(string: str).isAbsolute {
-            self.init(str)
+            try self.init(validating: str)
         } else {
 #if os(Windows)
             assert(!basePath.pathString.isEmpty)
@@ -115,7 +106,11 @@ public struct AbsolutePath: Hashable {
         self.init(absPath, RelativePath(relStr))
     }
 
-    /// Convenience initializer that verifies that the path is absolute.
+    /// Initializes the AbsolutePath from `absStr`, which must be an absolute
+    /// path (i.e. it must begin with a path separator; this initializer does
+    /// not interpret leading `~` characters as home directory specifiers).
+    /// The input string will be normalized if needed, as described in the
+    /// documentation for AbsolutePath.
     public init(validating path: String) throws {
         try self.init(PathImpl(validatingAbsolutePath: path))
     }
@@ -1065,3 +1060,17 @@ private func mayNeedNormalization(absolute string: String) -> Bool {
     }
     return false
 }
+
+// MARK: - `AbsolutePath` backwards compatibility, delete after deprecation period.
+
+extension AbsolutePath {
+    @available(*, deprecated, message: "use throwing variant instead")
+    public init(_ absStr: String) {
+        try! self.init(validating: absStr)
+    }
+
+    @available(*, deprecated, message: "use throwing variant instead")
+    public init(_ str: String, relativeTo basePath: AbsolutePath) {
+        try! self.init(validating: str, relativeTo: basePath)
+    }
+}

Sources/TSCBasic/PathShims.swift

@@ -21,20 +21,20 @@ import TSCLibc
 import Foundation
 
 /// Returns the "real path" corresponding to `path` by resolving any symbolic links.
-public func resolveSymlinks(_ path: AbsolutePath) -> AbsolutePath {
+public func resolveSymlinks(_ path: AbsolutePath) throws -> AbsolutePath {
 #if os(Windows)
     let handle: HANDLE = path.pathString.withCString(encodedAs: UTF16.self) {
       CreateFileW($0, GENERIC_READ, DWORD(FILE_SHARE_READ), nil,
                   DWORD(OPEN_EXISTING), DWORD(FILE_FLAG_BACKUP_SEMANTICS), nil)
     }
     if handle == INVALID_HANDLE_VALUE { return path }
     defer { CloseHandle(handle) }
-    return withUnsafeTemporaryAllocation(of: WCHAR.self, capacity: 261) {
+    return try withUnsafeTemporaryAllocation(of: WCHAR.self, capacity: 261) {
       let dwLength: DWORD =
             GetFinalPathNameByHandleW(handle, $0.baseAddress!, DWORD($0.count),
                                       DWORD(FILE_NAME_NORMALIZED))
       let path = String(decodingCString: $0.baseAddress!, as: UTF16.self)
-      return try! AbsolutePath(validating: path)
+      return try AbsolutePath(path)
     }
 #else
     let pathStr = path.pathString
@@ -51,7 +51,7 @@ public func resolveSymlinks(_ path: AbsolutePath) -> AbsolutePath {
         // null-terminated UTF-8 data referenced by the given pointer.
         resultPtr.deallocate()
         // FIXME: We should measure if it's really more efficient to compare the strings first.
-        return result == pathStr ? path : AbsolutePath(result)
+        return result == pathStr ? path : try AbsolutePath(validating: result)
     }
 
     return path
@@ -72,13 +72,6 @@ public func createSymlink(_ path: AbsolutePath, pointingAt dest: AbsolutePath, r
     try FileManager.default.createSymbolicLink(atPath: path.pathString, withDestinationPath: destString)
 }
 
-/// The current working directory of the processs.
-@available(*, deprecated, renamed: "localFileSystem.currentWorkingDirectory")
-public var currentWorkingDirectory: AbsolutePath {
-    let cwdStr = FileManager.default.currentDirectoryPath
-    return AbsolutePath(cwdStr)
-}
-
 /**
  - Returns: a generator that walks the specified directory producing all
  files therein. If recursively is true will enter any directories

Sources/TSCBasic/TemporaryFile.swift

@@ -53,7 +53,7 @@ private extension TempFileError {
 ///
 /// - Returns: Path to directory in which temporary file should be created.
 public func determineTempDirectory(_ dir: AbsolutePath? = nil) throws -> AbsolutePath {
-    let tmpDir = dir ?? localFileSystem.tempDirectory
+    let tmpDir = try dir ?? localFileSystem.tempDirectory
     guard localFileSystem.isDirectory(tmpDir) else {
         throw TempFileError.couldNotFindTmpDir(tmpDir.pathString)
     }
@@ -87,7 +87,7 @@ public struct TemporaryFile {
         // Determine in which directory to create the temporary file.
         self.dir = try determineTempDirectory(dir)
         // Construct path to the temporary file.
-        let path = AbsolutePath(prefix + ".XXXXXX" + suffix, relativeTo: self.dir)
+        let path = try AbsolutePath(validating: prefix + ".XXXXXX" + suffix, relativeTo: self.dir)
 
         // Convert path to a C style string terminating with null char to be an valid input
         // to mkstemps method. The XXXXXX in this string will be replaced by a random string
@@ -98,7 +98,7 @@ public struct TemporaryFile {
         // If mkstemps failed then throw error.
         if fd == -1 { throw TempFileError(errno: errno) }
 
-        self.path = AbsolutePath(String(cString: template))
+        self.path = try AbsolutePath(validating: String(cString: template))
         fileHandle = FileHandle(fileDescriptor: fd, closeOnDealloc: true)
     }
 }
@@ -236,7 +236,7 @@ public func withTemporaryDirectory<Result>(
     dir: AbsolutePath? = nil, prefix: String = "TemporaryDirectory" , _ body: (AbsolutePath, @escaping (AbsolutePath) -> Void) throws -> Result
 ) throws -> Result {
     // Construct path to the temporary directory.
-    let templatePath = try AbsolutePath(prefix + ".XXXXXX", relativeTo: determineTempDirectory(dir))
+    let templatePath = try AbsolutePath(validating: prefix + ".XXXXXX", relativeTo: determineTempDirectory(dir))
 
     // Convert templatePath to a C style string terminating with null char to be an valid input
     // to mkdtemp method. The XXXXXX in this string will be replaced by a random string
@@ -247,7 +247,7 @@ public func withTemporaryDirectory<Result>(
         throw MakeDirectoryError(errno: errno)
     }
 
-    return try body(AbsolutePath(String(cString: template))) { path in
+    return try body(AbsolutePath(validating: String(cString: template))) { path in
         _ = try? FileManager.default.removeItem(atPath: path.pathString)
     }
 }