Ability To Turn Off Formatting For Subdirectory

Documentation/Configuration.md

@@ -11,6 +11,9 @@ top-level keys and values:
 *   `version` _(number)_: The version of the configuration file. For now, this
     should always be `1`.
 
+*   `skipAll` _(boolean)_: If this is true, all other configuration 
+    options are ignored, and formatting/linting is disabled.
+
 *   `lineLength` _(number)_: The maximum allowed length of a line, in
     characters.
 

README.md

@@ -201,14 +201,21 @@ configuration, by redirecting it to a file and editing it.
 ### Configuring the Command Line Tool
 
 For any source file being checked or formatted, `swift-format` looks for a
-JSON-formatted file named `.swift-format` in the same directory. If one is
-found, then that file is loaded to determine the tool's configuration. If the
-file is not found, then it looks in the parent directory, and so on.
-
-If no configuration file is found, a default configuration is used. The
-settings in the default configuration can be viewed by running
-`swift-format dump-configuration`, which will dump it to standard
-output.
+JSON-formatted file named `.no-swift-format` in the same directory. 
+The presence of this file will disable all formatting and linting. 
+The contents of `.no-swift-format`  are ignored - it can be an empty file.
+
+If the file is not found, then it looks in the same directory for a file
+called `.swift-format`. If one is found, then that file is loaded to 
+determine the tool's configuration. 
+
+If neither configuration file is found, the search for files continues 
+in the parent directory, and so on.
+
+If no configuration file is found at any level, a default configuration 
+is used. The settings in the default configuration can be viewed by
+running `swift-format dump-configuration`, which will dump it to 
+standard output.
 
 If the `--configuration <file>` option is passed to `swift-format`, then that
 configuration will be used unconditionally and the file system will not be

Sources/SwiftFormat/API/Configuration.swift

@@ -24,8 +24,19 @@ internal let highestSupportedConfigurationVersion = 1
 /// Holds the complete set of configured values and defaults.
 public struct Configuration: Codable, Equatable {
 
+  /// Name of the configuration file to look for.
+  /// The presence of this file in a directory will cause the formatter
+  /// to use the configuration specified in that file.
+  private static let configurationFileName = ".swift-format"
+
+  /// Name of the suppression file to look for.
+  /// The presence of this file in a directory will cause the formatter
+  /// to skip formatting files in that directory and its subdirectories.
+  private static let suppressionFileName = ".no-swift-format"
+
   private enum CodingKeys: CodingKey {
     case version
+    case skipAll
     case maximumBlankLines
     case lineLength
     case spacesBeforeEndOfLineComments
@@ -59,6 +70,9 @@ public struct Configuration: Codable, Equatable {
 
   /// MARK: Common configuration
 
+  /// Is all formatting disbled?
+  public var skipAll = false
+
   /// The dictionary containing the rule names that we wish to run on. A rule is not used if it is
   /// marked as `false`, or if it is missing from the dictionary.
   public var rules: [String: Bool]
@@ -262,6 +276,13 @@ public struct Configuration: Codable, Equatable {
 
   /// Creates a new `Configuration` by loading it from a configuration file.
   public init(contentsOf url: URL) throws {
+    if url.lastPathComponent == Self.suppressionFileName {
+      var config = Configuration()
+      config.skipAll = true
+      self = config
+      return
+    }
+
     let data = try Data(contentsOf: url)
     try self.init(data: data)
   }
@@ -295,6 +316,9 @@ public struct Configuration: Codable, Equatable {
     // default-initialized instance.
     let defaults = Configuration()
 
+    self.skipAll = 
+      try container.decodeIfPresent(Bool.self, forKey: .skipAll) 
+      ?? false
     self.maximumBlankLines =
       try container.decodeIfPresent(Int.self, forKey: .maximumBlankLines)
       ?? defaults.maximumBlankLines
@@ -382,6 +406,7 @@ public struct Configuration: Codable, Equatable {
     var container = encoder.container(keyedBy: CodingKeys.self)
 
     try container.encode(version, forKey: .version)
+    try container.encode(skipAll, forKey: .skipAll)
     try container.encode(maximumBlankLines, forKey: .maximumBlankLines)
     try container.encode(lineLength, forKey: .lineLength)
     try container.encode(spacesBeforeEndOfLineComments, forKey: .spacesBeforeEndOfLineComments)
@@ -426,7 +451,11 @@ public struct Configuration: Codable, Equatable {
     }
     repeat {
       candidateDirectory.deleteLastPathComponent()
-      let candidateFile = candidateDirectory.appendingPathComponent(".swift-format")
+      let suppressingFile = candidateDirectory.appendingPathComponent(Self.suppressionFileName)
+      if FileManager.default.isReadableFile(atPath: suppressingFile.path) {
+        return suppressingFile
+      }
+      let candidateFile = candidateDirectory.appendingPathComponent(Self.configurationFileName)
       if FileManager.default.isReadableFile(atPath: candidateFile.path) {
         return candidateFile
       }

Sources/SwiftFormat/API/SwiftFormatter.swift

@@ -106,6 +106,12 @@ public final class SwiftFormatter {
     // also does not touch an empty file even if the setting to add trailing newlines is enabled.)
     guard !source.isEmpty else { return }
 
+    // If skipAll is set, just emit the source as-is.
+    guard !configuration.skipAll else {
+      outputStream.write(source)
+      return
+    }
+
     let sourceFile = try parseAndEmitDiagnostics(
       source: source,
       operatorTable: .standardOperators,

Sources/SwiftFormat/API/SwiftLinter.swift

@@ -94,6 +94,11 @@ public final class SwiftLinter {
     // also does not touch an empty file even if the setting to add trailing newlines is enabled.)
     guard !source.isEmpty else { return }
 
+    // If skipAll is set, do nothing.
+    guard !configuration.skipAll else {
+      return
+    }
+
     let sourceFile = try parseAndEmitDiagnostics(
       source: source,
       operatorTable: .standardOperators,