Improved errors for R.swift 5 (mac-cain13#469)

* Collect all commandline argument errors, and show them at once

* Only touch file when running generate command. To prevent warnings when using --help or --version

* Move Rswift environment validation to separate file

Sources/RswiftCore/CallInformation.swift

@@ -26,11 +26,11 @@ public struct CallInformation {
   let scriptOutputFiles: [String]
   let lastRunURL: URL
 
-  private let buildProductsDirURL: URL
-  private let developerDirURL: URL
-  private let sourceRootURL: URL
-  private let sdkRootURL: URL
-  private let platformURL: URL
+  let buildProductsDirURL: URL
+  let developerDirURL: URL
+  let sourceRootURL: URL
+  let sdkRootURL: URL
+  let platformURL: URL
 
   public init(
     outputURL: URL,

Sources/RswiftCore/EnvironmentValidation.swift

@@ -0,0 +1,61 @@
+//
+//  EnvironmentValidation.swift
+//  Commander
+//
+//  Created by Tom Lokhorst on 2018-12-12.
+//
+
+import Foundation
+
+public func validateRswiftEnvironment(
+  outputURL: URL,
+  sourceRootPath: String,
+  scriptInputFiles: [String],
+  scriptOutputFiles: [String],
+  lastRunURL: URL,
+  podsRoot: String?,
+  commandLineArguments: [String]) -> [String]
+{
+  var errors: [String] = []
+  var outputIsDirectory = false
+
+  if outputURL.pathExtension != "swift" {
+    outputIsDirectory = true
+
+    var error = "Output path must specify a file, it should not be a directory."
+    if FileManager.default.directoryExists(atPath: outputURL.path) {
+      let rswiftGeneratedFile = outputURL.appendingPathComponent("R.generated.swift").path
+      let commandParts = commandLineArguments
+        .map { $0.replacingOccurrences(of: podsRoot ?? "", with: "$PODS_ROOT") }
+        .map { $0.replacingOccurrences(of: outputURL.path, with: rswiftGeneratedFile) }
+        .map { $0.replacingOccurrences(of: sourceRootPath, with: "$SRCROOT") }
+        .map { $0.contains(" ") ? "\"\($0)\"" : $0 }
+      error += "\nExample: " + commandParts.joined(separator: " ")
+    }
+
+    errors.append(error)
+  }
+
+  if !scriptInputFiles.contains(lastRunURL.path) {
+    errors.append("Build phase Intput Files does not contain '$TEMP_DIR/\(lastRunURL.lastPathComponent)'.")
+  }
+
+  if !scriptOutputFiles.contains(outputURL.path) {
+    var prettyPath = outputURL.path.replacingOccurrences(of: sourceRootPath, with: "$SRCROOT")
+    if outputIsDirectory {
+      prettyPath += "/R.generated.swift"
+    }
+    errors.append("Build phase Output Files do not contain '\(prettyPath)'.")
+  }
+
+  return errors
+}
+
+extension FileManager {
+  func directoryExists(atPath path: String) -> Bool {
+    var isDir: ObjCBool = false
+    let exists = fileExists(atPath: path, isDirectory: &isDir)
+
+    return exists && isDir.boolValue
+  }
+}

Sources/RswiftCore/RswiftCore.swift

@@ -13,21 +13,6 @@ import XcodeEdit
 public struct RswiftCore {
 
   static public func run(_ callInformation: CallInformation) throws {
-    guard callInformation.scriptInputFiles.contains(callInformation.lastRunURL.path) else {
-      fail("Missing '$(TEMP_DIR)/\(callInformation.lastRunURL.lastPathComponent)' from Input Files. See upgrading to R.swift 5.0: http://bit.ly/2PsO9IF")
-      exit(EXIT_FAILURE)
-    }
-
-    guard callInformation.outputURL.pathExtension == "swift" else {
-      fail("Output path must be a specific Swift file, folders are not allowed anymore. See upgrading to R.swift 5.0: http://bit.ly/2PsO9IF")
-      exit(EXIT_FAILURE)
-    }
-
-    guard callInformation.scriptOutputFiles.contains(callInformation.outputURL.path) else {
-      fail("Build phase output files do not contain '\(callInformation.outputURL.path)'. See upgrading to R.swift 5.0: http://bit.ly/2PsO9IF")
-      exit(EXIT_FAILURE)
-    }
-
     do {
       let xcodeproj = try Xcodeproj(url: callInformation.xcodeprojURL)
       let ignoreFile = (try? IgnoreFile(ignoreFileURL: callInformation.rswiftIgnoreURL)) ?? IgnoreFile()

Sources/RswiftCore/Util/ErrorOutput.swift

@@ -13,6 +13,6 @@ public func warn(_ warning: String) {
   print("warning: [R.swift] \(warning)")
 }
 
-func fail(_ error: String) {
+public func fail(_ error: String) {
   print("error: [R.swift] \(error)")
 }

Sources/rswift/main.swift

@@ -85,6 +85,15 @@ let generate = command(
 
   let processInfo = ProcessInfo()
 
+  // Touch last run file
+  do {
+    let tempDirPath = try ProcessInfo().environmentVariable(name: EnvironmentKeys.tempDir)
+    let lastRunFile = URL(fileURLWithPath: tempDirPath).appendingPathComponent(Rswift.lastRunFile)
+    try Date().description.write(to: lastRunFile, atomically: true, encoding: .utf8)
+  } catch {
+    warn("Failed to write out to '\(Rswift.lastRunFile)', this might cause Xcode to not run the R.swift build phase: \(error)")
+  }
+
   let xcodeprojPath = try processInfo.environmentVariable(name: EnvironmentKeys.xcodeproj)
   let targetName = try processInfo.environmentVariable(name: EnvironmentKeys.target)
   let bundleIdentifier = try processInfo.environmentVariable(name: EnvironmentKeys.bundleIdentifier)
@@ -105,6 +114,8 @@ let generate = command(
     .filter { !$0.isEmpty }
     .map { Module.custom(name: $0) }
 
+  let lastRunURL = URL(fileURLWithPath: tempDir).appendingPathComponent(Rswift.lastRunFile)
+
   let scriptInputFileCountString = try processInfo.environmentVariable(name: EnvironmentKeys.scriptInputFileCount)
   guard let scriptInputFileCount = Int(scriptInputFileCountString) else {
     throw ArgumentError.invalidType(value: scriptInputFileCountString, type: "Int", argument: EnvironmentKeys.scriptInputFileCount)
@@ -121,6 +132,22 @@ let generate = command(
     .map(EnvironmentKeys.scriptOutputFile)
     .map(processInfo.environmentVariable)
 
+  let errors = validateRswiftEnvironment(
+    outputURL: outputURL,
+    sourceRootPath: sourceRootPath,
+    scriptInputFiles: scriptInputFiles,
+    scriptOutputFiles: scriptOutputFiles,
+    lastRunURL: lastRunURL,
+    podsRoot: processInfo.environment["PODS_ROOT"],
+    commandLineArguments: CommandLine.arguments)
+  guard errors.isEmpty else {
+    for error in errors {
+      fail(error)
+    }
+    warn("For updating to R.swift 5.0, read our migration guide: https://github.com/mac-cain13/R.swift/blob/master/Documentation/Migration.md")
+    exit(EXIT_FAILURE)
+  }
+
   let callInformation = CallInformation(
     outputURL: outputURL,
     rswiftIgnoreURL: rswiftIgnoreURL,
@@ -135,7 +162,7 @@ let generate = command(
 
     scriptInputFiles: scriptInputFiles,
     scriptOutputFiles: scriptOutputFiles,
-    lastRunURL: URL(fileURLWithPath: tempDir).appendingPathComponent(Rswift.lastRunFile),
+    lastRunURL: lastRunURL,
 
     buildProductsDirURL: URL(fileURLWithPath: buildProductsDirPath),
     developerDirURL: URL(fileURLWithPath: developerDirPath),
@@ -147,15 +174,6 @@ let generate = command(
   try RswiftCore.run(callInformation)
 }
 
-// Touch last run file
-do {
-  let tempDirPath = try ProcessInfo().environmentVariable(name: EnvironmentKeys.tempDir)
-  let lastRunFile = URL(fileURLWithPath: tempDirPath).appendingPathComponent(Rswift.lastRunFile)
-  try Date().description.write(to: lastRunFile, atomically: true, encoding: .utf8)
-} catch {
-  warn("Failed to write out to '\(Rswift.lastRunFile)', this might cause Xcode to not run the R.swift build phase: \(error)")
-}
-
 // Start parsing the launch arguments
 let group = Group()
 group.addCommand("generate", "Generates R.generated.swift file", generate)