Fix error message for invalid subcommands

zio-cli/shared/src/main/scala/zio/cli/Command.scala

@@ -3,7 +3,7 @@ package zio.cli
 import zio.cli.HelpDoc.h1
 import zio.cli.ValidationErrorType.CommandMismatch
 import zio.cli.oauth2.OAuth2PlatformSpecific
-import zio.{IO, ZIO}
+import zio.{Chunk, IO, ZIO}
 
 /**
  * A `Command` represents a command in a command-line application. Every command-line application will have at least one
@@ -35,6 +35,8 @@ sealed trait Command[+A] extends Parameter with Named { self =>
  subcommands.copy(parent = subcommands.parent.withHelp(help)).asInstanceOf[Command[A]]
  }
 
+ def getSubcommands: Map[String, Command[_]]
+
  def helpDoc: HelpDoc
 
  final def map[B](f: A => B): Command[B] = Command.Map(self, f)
@@ -158,6 +160,8 @@ object Command {
  UsageSynopsis.Named(List(self.name), None) + self.options.synopsis + self.args.synopsis
 
  def pipeline = ("", List(options, args))
+
+ def getSubcommands: Predef.Map[String, Command[_]] = Predef.Map(self.name -> self)
  }
 
  final case class Map[A, B](command: Command[A], f: A => B) extends Command[B] with Pipeline with Wrap { self =>
@@ -178,6 +182,8 @@ object Command {
  override def wrapped: Command[A] = self.command
 
  def pipeline = ("", List(command))
+
+ def getSubcommands: Predef.Map[String, Command[_]] = self.command.getSubcommands
  }
 
  final case class OrElse[A](left: Command[A], right: Command[A]) extends Command[A] with Alternatives { self =>
@@ -195,6 +201,7 @@ object Command {
 
  override val alternatives = List(left, right)
 
+ def getSubcommands: Predef.Map[String, Command[_]] = self.left.getSubcommands ++ self.right.getSubcommands
  }
 
  final case class Subcommands[A, B](parent: Command[A], child: Command[B]) extends Command[(A, B)] with Pipeline {
@@ -282,14 +289,32 @@ object Command {
 
  self.parent
  .parse(args, conf)
+ .debug("Subcommand parent parse")
  .flatMap {
  case CommandDirective.BuiltIn(BuiltInOption.ShowHelp(_, _)) =>
  helpDirectiveForChild orElse helpDirectiveForParent
  case CommandDirective.BuiltIn(BuiltInOption.ShowWizard(_)) =>
  wizardDirectiveForChild orElse wizardDirectiveForParent
  case builtIn @ CommandDirective.BuiltIn(_) => ZIO.succeed(builtIn)
  case CommandDirective.UserDefined(leftover, a) if leftover.nonEmpty =>
- self.child.parse(leftover, conf).map(_.map((a, _)))
+ self.child
+ .parse(leftover, conf)
+ .mapBoth(
+ {
+ case ValidationError(CommandMismatch, _) =>
+ val parentName = self.names.headOption.getOrElse("")
+ val subCommandNames = Chunk.fromIterable(self.getSubcommands.keys).map(n => s"'$n'")
+ val oneOf = if (subCommandNames.size == 1) "" else " one of"
+ ValidationError(
+ CommandMismatch,
+ HelpDoc.p(
+ s"Invalid subcommand for ${parentName}. Use$oneOf ${subCommandNames.mkString(", ")}"
+ )
+ )
+ case other: ValidationError => other
+ },
+ _.map((a, _))
+ )
  case _ =>
  helpDirectiveForParent
  }
@@ -302,6 +327,8 @@ object Command {
  lazy val synopsis: UsageSynopsis = self.parent.synopsis + self.child.synopsis
 
  def pipeline = ("", List(parent, child))
+
+ def getSubcommands: Predef.Map[String, Command[_]] = self.child.getSubcommands
  }
 
  /**

zio-cli/shared/src/test/scala/zio/cli/CommandSpec.scala

@@ -117,6 +117,13 @@ object CommandSpec extends ZIOSpecDefault {
  assertZIO(git.parse(List("git", "log"), CliConfig.default))(
  equalTo(CommandDirective.UserDefined(Nil, ()))
  )
+ },
+ test("test unknown sub command error message") {
+ assertZIO(git.parse(List("git", "abc"), CliConfig.default).flip.map { e =>
+ e.error
+ })(
+ equalTo(HelpDoc.p("Invalid subcommand for git. Use one of 'remote', 'log'"))
+ )
  }
  )
  }: _*),
@@ -149,6 +156,13 @@ object CommandSpec extends ZIOSpecDefault {
  equalTo(ValidationErrorType.CommandMismatch)
  )
  },
+ test("test unknown sub command error message") {
+ assertZIO(git.parse(List("git", "abc"), CliConfig.default).flip.map { e =>
+ e.error
+ })(
+ equalTo(HelpDoc.p("Invalid subcommand for git. Use 'rebase'"))
+ )
+ },
  test("test without sub command") {
  git.parse(List("git"), CliConfig.default).map { result =>
  assertTrue {