Make ParsableCommand.run() a mutating method (#163)

natecook1000 · nuclearace · web-flow · commit aad1ac085b72 · 2020-06-02T14:07:16.000-05:00
Co-authored-by: Erik Little &lt;nuclear.ace@gmail.com&gt;
diff --git a/Documentation/01 Getting Started.md b/Documentation/01 Getting Started.md
@@ -52,7 +52,7 @@ struct Count: ParsableCommand {
     @Argument()
     var outputFile: String
     
-    func run() throws {
+    mutating func run() throws {
         print("""
             Counting words in '\(inputFile)' \
             and writing the result into '\(outputFile)'.
@@ -91,7 +91,7 @@ struct Count: ParsableCommand {
     @Option()
     var outputFile: String
     
-    func run() throws {
+    mutating func run() throws {
         print("""
             Counting words in '\(inputFile)' \
             and writing the result into '\(outputFile)'.
@@ -135,7 +135,7 @@ struct Count: ParsableCommand {
     @Flag()
     var verbose: Bool
     
-    func run() throws {
+    mutating func run() throws {
         if verbose {
             print("""
                 Counting words in '\(inputFile)' \
@@ -177,7 +177,7 @@ struct Count: ParsableCommand {
     @Flag(name: .shortAndLong)
     var verbose: Bool
     
-    func run() throws { ... }
+    mutating func run() throws { ... }
 }
 ```
 
@@ -211,7 +211,7 @@ struct Count: ParsableCommand {
     @Flag(name: .shortAndLong, help: "Print status updates while counting.")
     var verbose: Bool
 
-    func run() throws { ... }
+    mutating func run() throws { ... }
 }
 ```
 
@@ -246,7 +246,7 @@ struct Count: ParsableCommand {
     @Flag(name: .shortAndLong, help: "Print status updates while counting.")
     var verbose: Bool
 
-    func run() throws {
+    mutating func run() throws {
         if verbose {
             print("""
                 Counting words in '\(inputFile)' \
diff --git a/Documentation/02 Arguments, Options, and Flags.md b/Documentation/02 Arguments, Options, and Flags.md
@@ -143,7 +143,7 @@ enum ReleaseMode: String, ExpressibleByArgument {
 struct Example: ParsableCommand {
     @Option() var mode: ReleaseMode
     
-    func run() throws {
+    mutating func run() throws {
         print(mode)
     }
 }
@@ -194,7 +194,7 @@ struct Example: ParsableCommand {
     @Flag(default: nil, inversion: .prefixedEnableDisable)
     var requiredElement: Bool
     
-    func run() throws {
+    mutating func run() throws {
         print(index, requiredElement)
     }
 }
@@ -230,7 +230,7 @@ struct Example: ParsableCommand {
     
     @Flag() var colors: [Color]
     
-    func run() throws {
+    mutating func run() throws {
         print(cacheMethod)
         print(colors)
     }
@@ -254,7 +254,7 @@ struct Example: ParsableCommand {
     @Flag(name: .shortAndLong)
     var verbose: Int
     
-    func run() throws {
+    mutating func run() throws {
         print("Verbosity level: \(verbose)")
     }
 }
@@ -281,7 +281,7 @@ struct Example: ParsableCommand {
     @Option() var name: String
     @Argument() var file: String?
     
-    func run() throws {
+    mutating func run() throws {
         print("Verbose: \(verbose), name: \(name), file: \(file ?? "none")")
     }
 }
@@ -327,7 +327,7 @@ struct Example: ParsableCommand {
     @Option() var file: [String]
     @Flag() var verbose: Bool
     
-    func run() throws {
+    mutating func run() throws {
         print("Verbose: \(verbose), files: \(file)")
     }
 }
@@ -378,7 +378,7 @@ struct Example: ParsableCommand {
     @Flag() var verbose: Bool
     @Argument() var files: [String]
     
-    func run() throws {
+    mutating func run() throws {
         print("Verbose: \(verbose), files: \(files)")
     }
 }
diff --git a/Documentation/03 Commands and Subcommands.md b/Documentation/03 Commands and Subcommands.md
@@ -74,7 +74,7 @@ extension Math {
         @OptionGroup()
         var options: Math.Options
         
-        func run() {
+        mutating func run() {
             let result = options.values.reduce(0, +)
             print(format(result: result, usingHex: options.hexadecimalOutput))
         }
@@ -87,7 +87,7 @@ extension Math {
         @OptionGroup()
         var options: Math.Options
         
-        func run() {
+        mutating func run() {
             let result = options.values.reduce(1, *)
             print(format(result: result, usingHex: options.hexadecimalOutput))
         }
@@ -130,7 +130,7 @@ extension Math.Statistics {
         func calculateMedian() -> Double { ... }
         func calculateMode() -> [Double] { ... }
     
-        func run() {
+        mutating func run() {
             switch kind {
             case .mean:
                 print(calculateMean())
@@ -153,7 +153,7 @@ extension Math.Statistics {
         @Argument(help: "A group of floating-point values to operate on.")
         var values: [Double]
         
-        func run() {
+        mutating func run() {
             if values.isEmpty {
                 print(0.0)
             } else {
diff --git a/Documentation/04 Customizing Help.md b/Documentation/04 Customizing Help.md
@@ -87,7 +87,7 @@ struct Repeat: ParsableCommand {
     @Argument(help: "The phrase to repeat.")
     var phrase: String
     
-    func run() throws {
+    mutating func run() throws {
         while true { print(phrase) }
     }
 }
@@ -131,7 +131,7 @@ struct Example: ParsableCommand {
     @Option(name: .shortAndLong, help: "The number of history entries to show.")
     var historyDepth: Int
     
-    func run() throws {
+    mutating func run() throws {
         printHistory(depth: historyDepth)
     }
 }
diff --git a/Documentation/05 Validation and Errors.md b/Documentation/05 Validation and Errors.md
@@ -32,7 +32,7 @@ struct Select: ParsableCommand {
         }
     }
     
-    func run() {
+    mutating func run() {
         print(elements.shuffled().prefix(count).joined(separator: "\n"))
     }
 }
@@ -66,7 +66,7 @@ The `ValidationError` type is a special `ArgumentParser` error — a validation
 struct LineCount: ParsableCommand {
     @Argument() var file: String
     
-    func run() throws {
+    mutating func run() throws {
         let contents = try String(contentsOfFile: file, encoding: .utf8)
         let lines = contents.split(separator: "\n")
         print(lines.count)
@@ -94,7 +94,7 @@ struct RuntimeError: Error, CustomStringConvertible {
 struct Example: ParsableCommand {
     @Argument() var inputFile: String
     
-    func run() throws {
+    mutating func run() throws {
         if !ExampleCore.processFile(inputFile) {
             // ExampleCore.processFile(_:) prints its own errors
             // and returns `false` on failure.
diff --git a/Documentation/06 Manual Parsing and Testing.md b/Documentation/06 Manual Parsing and Testing.md
@@ -56,10 +56,10 @@ Let's see how this works by using the `Math` command and subcommands defined in
 
 ```swift
 do {
-    let command = try Math.parseAsRoot()
+    var command = try Math.parseAsRoot()
 
     switch command {
-    case let command as Math.Add:
+    case var command as Math.Add:
         print("You chose to add \(command.options.values.count) values.")
         command.run()
     default:
diff --git a/Examples/math/main.swift b/Examples/math/main.swift
@@ -57,7 +57,7 @@ extension Math {
         @OptionGroup()
         var options: Options
         
-        func run() {
+        mutating func run() {
             let result = options.values.reduce(0, +)
             print(format(result, usingHex: options.hexadecimalOutput))
         }
@@ -70,7 +70,7 @@ extension Math {
         @OptionGroup()
         var options: Options
         
-        func run() {
+        mutating func run() {
             let result = options.values.reduce(1, *)
             print(format(result, usingHex: options.hexadecimalOutput))
         }
@@ -145,7 +145,7 @@ extension Math.Statistics {
                 .map { k, _ in k }
         }
     
-        func run() {
+        mutating func run() {
             switch kind {
             case .mean:
                 print(calculateMean())
@@ -168,7 +168,7 @@ extension Math.Statistics {
         @Argument(help: "A group of floating-point values to operate on.")
         var values: [Double]
         
-        func run() {
+        mutating func run() {
             if values.isEmpty {
                 print(0.0)
             } else {
diff --git a/Examples/repeat/main.swift b/Examples/repeat/main.swift
@@ -21,7 +21,7 @@ struct Repeat: ParsableCommand {
     @Argument(help: "The phrase to repeat.")
     var phrase: String
 
-    func run() throws {
+    mutating func run() throws {
         let repeatCount = count ?? .max
 
         for i in 1...repeatCount {
diff --git a/README.md b/README.md
@@ -21,7 +21,7 @@ struct Repeat: ParsableCommand {
     @Argument(help: "The phrase to repeat.")
     var phrase: String
 
-    func run() throws {
+    mutating func run() throws {
         let repeatCount = count ?? .max
 
         for i in 1...repeatCount {
diff --git a/Sources/ArgumentParser/Parsable Types/EnumerableFlag.swift b/Sources/ArgumentParser/Parsable Types/EnumerableFlag.swift
@@ -22,7 +22,7 @@
 ///     struct Example: ParsableCommand {
 ///         @Flag() var sizes: [Size]
 ///
-///         func run() {
+///         mutating func run() {
 ///             print(sizes)
 ///         }
 ///     }
diff --git a/Sources/ArgumentParser/Parsable Types/ParsableCommand.swift b/Sources/ArgumentParser/Parsable Types/ParsableCommand.swift
@@ -28,7 +28,7 @@ public protocol ParsableCommand: ParsableArguments {
   /// application by calling the static `main()` method on the root type.
   /// This method has a default implementation that prints help text
   /// for this command.
-  func run() throws
+  mutating func run() throws
 }
 
 extension ParsableCommand {
@@ -41,7 +41,7 @@ extension ParsableCommand {
     CommandConfiguration()
   }
   
-  public func run() throws {
+  public mutating func run() throws {
     throw CleanExit.helpRequest(self)
   }
 }
@@ -91,7 +91,7 @@ extension ParsableCommand {
   ///   `arguments` is `nil`, this uses the program's command-line arguments.
   public static func main(_ arguments: [String]?) {
     do {
-      let command = try parseAsRoot(arguments)
+      var command = try parseAsRoot(arguments)
       try command.run()
     } catch {
       exit(withError: error)
diff --git a/Sources/ArgumentParser/Usage/HelpCommand.swift b/Sources/ArgumentParser/Usage/HelpCommand.swift
@@ -18,7 +18,7 @@ struct HelpCommand: ParsableCommand {
   
   init() {}
   
-  func run() throws {
+  mutating func run() throws {
     throw CommandError(commandStack: commandStack, parserError: .helpRequested)
   }
   
diff --git a/Sources/ArgumentParserTestHelpers/TestHelpers.swift b/Sources/ArgumentParserTestHelpers/TestHelpers.swift
@@ -29,7 +29,7 @@ public protocol TestableParsableCommand: ParsableCommand, TestableParsableArgume
 }
 
 public extension TestableParsableCommand {
-  func run() throws {
+  mutating func run() throws {
     didRunExpectation.fulfill()
   }
 }
diff --git a/Tests/ArgumentParserEndToEndTests/RepeatingEndToEndTests.swift b/Tests/ArgumentParserEndToEndTests/RepeatingEndToEndTests.swift
@@ -401,7 +401,7 @@ extension RepeatingEndToEndTests {
 struct PerformanceTest: ParsableCommand {
   @Option(name: .short) var bundleIdentifiers: [String]
   
-  func run() throws { print(bundleIdentifiers) }
+  mutating func run() throws { print(bundleIdentifiers) }
 }
 
 fileprivate func argumentGenerator(_ count: Int) -> [String] {
diff --git a/Tests/ArgumentParserEndToEndTests/SubcommandEndToEndTests.swift b/Tests/ArgumentParserEndToEndTests/SubcommandEndToEndTests.swift
@@ -127,7 +127,7 @@ fileprivate struct Math: ParsableCommand {
   @Argument(help: "The first operand")
   var operands: [Int]
   
-  func run() {
+  mutating func run() {
     XCTAssertEqual(operation, .multiply)
     XCTAssertTrue(verbose)
     XCTAssertEqual(operands, [5, 11])
@@ -137,7 +137,7 @@ fileprivate struct Math: ParsableCommand {
 
 extension SubcommandEndToEndTests {
   func testParsing_SingleCommand() throws {
-    let mathCommand = try Math.parseAsRoot(["--operation", "multiply", "-v", "5", "11"])
+    var mathCommand = try Math.parseAsRoot(["--operation", "multiply", "-v", "5", "11"])
     XCTAssertFalse(mathDidRun)
     try mathCommand.run()
     XCTAssertTrue(mathDidRun)
diff --git a/Tests/ArgumentParserPackageManagerTests/PackageManager/GenerateXcodeProject.swift b/Tests/ArgumentParserPackageManagerTests/PackageManager/GenerateXcodeProject.swift
@@ -38,7 +38,7 @@ extension Package {
     @Option(help: "Path to xcconfig file")
     var xcconfigOverrides: String?
     
-    func run() {
+    mutating func run() {
       print("Generating Xcode Project.......")
     }
   }
diff --git a/Tests/ArgumentParserUnitTests/ParsableArgumentsValidationTests.swift b/Tests/ArgumentParserUnitTests/ParsableArgumentsValidationTests.swift
@@ -26,7 +26,7 @@ final class ParsableArgumentsValidationTests: XCTestCase {
       case phrase
     }
     
-    func run() throws {}
+    mutating func run() throws {}
   }
   
   private struct B: ParsableCommand {
@@ -36,7 +36,7 @@ final class ParsableArgumentsValidationTests: XCTestCase {
     @Argument(help: "The phrase to repeat.")
     var phrase: String
     
-    func run() throws {}
+    mutating func run() throws {}
   }
   
   private struct C: ParsableCommand {
@@ -50,7 +50,7 @@ final class ParsableArgumentsValidationTests: XCTestCase {
       case phrase
     }
     
-    func run() throws {}
+    mutating func run() throws {}
   }
   
   private struct D: ParsableArguments {
diff --git a/Tools/changelog-authors/main.swift b/Tools/changelog-authors/main.swift
@@ -126,7 +126,7 @@ struct ChangelogAuthors: ParsableCommand {
     return url
   }
   
-  func run() throws {
+  mutating func run() throws {
     let data = try Data(contentsOf: try comparisonURL())
     let comparison = try JSONDecoder().decode(Comparison.self, from: data)
     let authors = comparison.commits.map({ $0.author })

Original file line number	Diff line number	Diff line change
`@@ -143,7 +143,7 @@ enum ReleaseMode: String, ExpressibleByArgument {`
`143`	`143`	`struct Example: ParsableCommand {`
`144`	`144`	`@Option() var mode: ReleaseMode`
`145`	`145`
`146`		`- func run() throws {`
	`146`	`+ mutating func run() throws {`
`147`	`147`	`print(mode)`
`148`	`148`	`}`
`149`	`149`	`}`
`@@ -194,7 +194,7 @@ struct Example: ParsableCommand {`
`194`	`194`	`@Flag(default: nil, inversion: .prefixedEnableDisable)`
`195`	`195`	`var requiredElement: Bool`
`196`	`196`
`197`		`- func run() throws {`
	`197`	`+ mutating func run() throws {`
`198`	`198`	`print(index, requiredElement)`
`199`	`199`	`}`
`200`	`200`	`}`
`@@ -230,7 +230,7 @@ struct Example: ParsableCommand {`
`230`	`230`
`231`	`231`	`@Flag() var colors: [Color]`
`232`	`232`
`233`		`- func run() throws {`
	`233`	`+ mutating func run() throws {`
`234`	`234`	`print(cacheMethod)`
`235`	`235`	`print(colors)`
`236`	`236`	`}`
`@@ -254,7 +254,7 @@ struct Example: ParsableCommand {`
`254`	`254`	`@Flag(name: .shortAndLong)`
`255`	`255`	`var verbose: Int`
`256`	`256`
`257`		`- func run() throws {`
	`257`	`+ mutating func run() throws {`
`258`	`258`	`print("Verbosity level: \(verbose)")`
`259`	`259`	`}`
`260`	`260`	`}`
`@@ -281,7 +281,7 @@ struct Example: ParsableCommand {`
`281`	`281`	`@Option() var name: String`
`282`	`282`	`@Argument() var file: String?`
`283`	`283`
`284`		`- func run() throws {`
	`284`	`+ mutating func run() throws {`
`285`	`285`	`print("Verbose: \(verbose), name: \(name), file: \(file ?? "none")")`
`286`	`286`	`}`
`287`	`287`	`}`
`@@ -327,7 +327,7 @@ struct Example: ParsableCommand {`
`327`	`327`	`@Option() var file: [String]`
`328`	`328`	`@Flag() var verbose: Bool`
`329`	`329`
`330`		`- func run() throws {`
	`330`	`+ mutating func run() throws {`
`331`	`331`	`print("Verbose: \(verbose), files: \(file)")`
`332`	`332`	`}`
`333`	`333`	`}`
`@@ -378,7 +378,7 @@ struct Example: ParsableCommand {`
`378`	`378`	`@Flag() var verbose: Bool`
`379`	`379`	`@Argument() var files: [String]`
`380`	`380`
`381`		`- func run() throws {`
	`381`	`+ mutating func run() throws {`
`382`	`382`	`print("Verbose: \(verbose), files: \(files)")`
`383`	`383`	`}`
`384`	`384`	`}`
Original file line number	Diff line number	Diff line change
`@@ -87,7 +87,7 @@ struct Repeat: ParsableCommand {`
`87`	`87`	`@Argument(help: "The phrase to repeat.")`
`88`	`88`	`var phrase: String`
`89`	`89`
`90`		`- func run() throws {`
	`90`	`+ mutating func run() throws {`
`91`	`91`	`while true { print(phrase) }`
`92`	`92`	`}`
`93`	`93`	`}`
`@@ -131,7 +131,7 @@ struct Example: ParsableCommand {`
`131`	`131`	`@Option(name: .shortAndLong, help: "The number of history entries to show.")`
`132`	`132`	`var historyDepth: Int`
`133`	`133`
`134`		`- func run() throws {`
	`134`	`+ mutating func run() throws {`
`135`	`135`	`printHistory(depth: historyDepth)`
`136`	`136`	`}`
`137`	`137`	`}`
Original file line number	Diff line number	Diff line change
`@@ -32,7 +32,7 @@ struct Select: ParsableCommand {`
`32`	`32`	`}`
`33`	`33`	`}`
`34`	`34`
`35`		`- func run() {`
	`35`	`+ mutating func run() {`
`36`	`36`	`print(elements.shuffled().prefix(count).joined(separator: "\n"))`
`37`	`37`	`}`
`38`	`38`	`}`
@@ -66,7 +66,7 @@ The `ValidationError` type is a special `ArgumentParser` error — a validation
`66`	`66`	`struct LineCount: ParsableCommand {`
`67`	`67`	`@Argument() var file: String`
`68`	`68`
`69`		`- func run() throws {`
	`69`	`+ mutating func run() throws {`
`70`	`70`	`let contents = try String(contentsOfFile: file, encoding: .utf8)`
`71`	`71`	`let lines = contents.split(separator: "\n")`
`72`	`72`	`print(lines.count)`
`@@ -94,7 +94,7 @@ struct RuntimeError: Error, CustomStringConvertible {`
`94`	`94`	`struct Example: ParsableCommand {`
`95`	`95`	`@Argument() var inputFile: String`
`96`	`96`
`97`		`- func run() throws {`
	`97`	`+ mutating func run() throws {`
`98`	`98`	`if !ExampleCore.processFile(inputFile) {`
`99`	`99`	`// ExampleCore.processFile(_:) prints its own errors`
`100`	`100`	// and returns `false` on failure.