Fixup help options for built-in flags (#474)

- Fixes a bug where built-in flags such as --help and --version were not
  properly marked with isOptional which resulted in them appearing in
  generated content (such as completion scripts and manuals) as required
  arguments.

Author: rauhul

Sources/ArgumentParser/Usage/HelpGenerator.swift

@@ -307,7 +307,10 @@ internal extension BidirectionalCollection where Element == ParsableCommand.Type
       else { return nil }
     return ArgumentDefinition(
       kind: .named([.long("version")]),
-      help: .init(help: "Show the version.", key: InputKey(rawValue: "")),
+      help: .init(
+        options: [.isOptional],
+        help: "Show the version.",
+        key: InputKey(rawValue: "")),
       completion: .default,
       update: .nullary({ _, _, _ in })
     )
@@ -318,7 +321,10 @@ internal extension BidirectionalCollection where Element == ParsableCommand.Type
     guard !names.isEmpty else { return nil }
     return ArgumentDefinition(
       kind: .named(names),
-      help: .init(help: "Show help information.", key: InputKey(rawValue: "")),
+      help: .init(
+        options: [.isOptional],
+        help: "Show help information.",
+        key: InputKey(rawValue: "")),
       completion: .default,
       update: .nullary({ _, _, _ in })
     )
@@ -328,6 +334,7 @@ internal extension BidirectionalCollection where Element == ParsableCommand.Type
     return ArgumentDefinition(
       kind: .named([.long("experimental-dump-help")]),
       help: .init(
+        options: [.isOptional],
         help: ArgumentHelp("Dump help information as JSON."),
         key: InputKey(rawValue: "")),
       completion: .default,

Tests/ArgumentParserGenerateManualTests/CountLinesGenerateManualTests.swift

@@ -29,7 +29,7 @@ final class CountLinesGenerateManualTests: XCTestCase {
       .Ar input-file
       .Op Fl -prefix Ar prefix
       .Op Fl -verbose
-      .Fl -help
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Ar input-file
@@ -71,7 +71,7 @@ final class CountLinesGenerateManualTests: XCTestCase {
       .Ar input-file
       .Op Fl -prefix Ar prefix
       .Op Fl -verbose
-      .Fl -help
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Ar input-file

Tests/ArgumentParserGenerateManualTests/MathGenerateManualTests.swift

@@ -26,8 +26,8 @@ final class MathGenerateManualTests: XCTestCase {
       .Sh SYNOPSIS
       .Nm
       .Ar subcommand
-      .Fl -version
-      .Fl -help
+      .Op Fl -version
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Fl -version
@@ -131,8 +131,8 @@ final class MathGenerateManualTests: XCTestCase {
       .Sh SYNOPSIS
       .Nm
       .Ar subcommand
-      .Fl -version
-      .Fl -help
+      .Op Fl -version
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Fl -version
@@ -168,8 +168,8 @@ final class MathGenerateManualTests: XCTestCase {
       .Nm
       .Op Fl -hex-output
       .Op Ar values...
-      .Fl -version
-      .Fl -help
+      .Op Fl -version
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Fl x , -hex-output
@@ -205,8 +205,8 @@ final class MathGenerateManualTests: XCTestCase {
       .Nm
       .Op Fl -hex-output
       .Op Ar values...
-      .Fl -version
-      .Fl -help
+      .Op Fl -version
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Fl x , -hex-output
@@ -241,8 +241,8 @@ final class MathGenerateManualTests: XCTestCase {
       .Sh SYNOPSIS
       .Nm
       .Ar subcommand
-      .Fl -version
-      .Fl -help
+      .Op Fl -version
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Fl -version
@@ -278,8 +278,8 @@ final class MathGenerateManualTests: XCTestCase {
       .Nm
       .Op Fl -kind Ar kind
       .Op Ar values...
-      .Fl -version
-      .Fl -help
+      .Op Fl -version
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Fl -kind Ar kind
@@ -314,8 +314,8 @@ final class MathGenerateManualTests: XCTestCase {
       .Sh SYNOPSIS
       .Nm
       .Op Ar values...
-      .Fl -version
-      .Fl -help
+      .Op Fl -version
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Ar values...
@@ -358,8 +358,8 @@ final class MathGenerateManualTests: XCTestCase {
       .Op Fl -directory Ar directory
       .Op Fl -shell Ar shell
       .Op Fl -custom Ar custom
-      .Fl -version
-      .Fl -help
+      .Op Fl -version
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Ar one-of-four

Tests/ArgumentParserGenerateManualTests/RepeatGenerateManualTests.swift

@@ -26,7 +26,7 @@ final class RepeatGenerateManualTests: XCTestCase {
       .Op Fl -count Ar count
       .Op Fl -include-counter
       .Ar phrase
-      .Fl -help
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Fl -count Ar count
@@ -67,7 +67,7 @@ final class RepeatGenerateManualTests: XCTestCase {
       .Op Fl -count Ar count
       .Op Fl -include-counter
       .Ar phrase
-      .Fl -help
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Fl -count Ar count

Tests/ArgumentParserGenerateManualTests/RollDiceGenerateManualTests.swift

@@ -27,7 +27,7 @@ final class RollDiceGenerateManualTests: XCTestCase {
       .Op Fl -sides Ar m
       .Op Fl -seed Ar seed
       .Op Fl -verbose
-      .Fl -help
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Fl -times Ar n
@@ -73,7 +73,7 @@ final class RollDiceGenerateManualTests: XCTestCase {
       .Op Fl -sides Ar m
       .Op Fl -seed Ar seed
       .Op Fl -verbose
-      .Fl -help
+      .Op Fl -help
       .Sh DESCRIPTION
       .Bl -tag -width 6n
       .It Fl -times Ar n