Add uninstallation functionality to the launcher (#1089)

build.sbt

@@ -808,20 +808,20 @@ lazy val parser = (project in file("lib/scala/parser"))
     fork := true,
     Cargo.rustVersion := rustVersion,
     Compile / compile / compileInputs := (Compile / compile / compileInputs)
-      .dependsOn(Cargo("build --project parser"))
-      .value,
+        .dependsOn(Cargo("build --project parser"))
+        .value,
     javaOptions += {
       val root = baseDirectory.value.getParentFile.getParentFile.getParentFile
       s"-Djava.library.path=$root/target/rust/debug"
     },
     libraryDependencies ++= Seq(
-      "com.storm-enroute" %% "scalameter" % scalameterVersion % "bench",
-      "org.scalatest" %%% "scalatest"     % scalatestVersion % Test,
-    ),
+        "com.storm-enroute" %% "scalameter" % scalameterVersion % "bench",
+        "org.scalatest"    %%% "scalatest"  % scalatestVersion  % Test
+      ),
     testFrameworks := List(
-      new TestFramework("org.scalatest.tools.Framework"),
-      new TestFramework("org.scalameter.ScalaMeterFramework")
-    ),
+        new TestFramework("org.scalatest.tools.Framework"),
+        new TestFramework("org.scalameter.ScalaMeterFramework")
+      )
   )
   .dependsOn(ast)
 
@@ -870,7 +870,7 @@ lazy val runtime = (project in file("engine/runtime"))
       ),
     bootstrap := CopyTruffleJAR.bootstrapJARs.value,
     Global / onLoad := EnvironmentCheck.addVersionCheck(
-        graalVersion,
+        s"GraalVM CE $graalVersion",
         javaVersion
       )((Global / onLoad).value)
   )

engine/launcher/src/main/scala/org/enso/launcher/FileSystem.scala

@@ -2,7 +2,12 @@ package org.enso.launcher
 
 import java.io.PrintWriter
 import java.nio.file.attribute.{PosixFilePermission, PosixFilePermissions}
-import java.nio.file.{Files, Path, StandardCopyOption}
+import java.nio.file.{
+  DirectoryNotEmptyException,
+  Files,
+  Path,
+  StandardCopyOption
+}
 import java.util
 
 import org.apache.commons.io.FileUtils
@@ -144,6 +149,34 @@ object FileSystem {
   def removeDirectory(dir: Path): Unit =
     FileUtils.deleteDirectory(dir.toFile)
 
+  /**
+    * Removes a directory recursively, does not fail if it does not exist.
+    */
+  def removeDirectoryIfExists(dir: Path): Unit =
+    if (Files.exists(dir))
+      FileUtils.deleteDirectory(dir.toFile)
+
+  /**
+    * Removes a directory only if it is empty.
+    *
+    * Returned value indicates if the directory has been removed.
+    */
+  def removeDirectoryIfEmpty(dir: Path): Boolean =
+    try {
+      Files.delete(dir)
+      true
+    } catch {
+      case _: DirectoryNotEmptyException =>
+        false
+    }
+
+  /**
+    * Removes a file, if it exists, does not fail if it does not exist.
+    */
+  def removeFileIfExists(path: Path): Unit =
+    if (Files.exists(path))
+      Files.delete(path)
+
   /**
     * Registers the directory to be removed when the program exits normally.
     *

engine/launcher/src/main/scala/org/enso/launcher/GlobalConfigurationManager.scala

@@ -39,5 +39,5 @@ object GlobalConfigurationManager {
   /**
     * Name of the main global configuration file.
     */
-  val globalConfigName: String = "global-config.yml"
+  val globalConfigName: String = "global-config.yaml"
 }

engine/launcher/src/main/scala/org/enso/launcher/cli/InternalOpts.scala

@@ -6,7 +6,8 @@ import java.nio.file.{Files, NoSuchFileException, Path}
 import org.enso.cli.Opts
 import org.enso.cli.Opts.implicits._
 import cats.implicits._
-import org.enso.launcher.OS
+import org.enso.launcher.{FileSystem, OS}
+import org.enso.launcher.FileSystem.PathSyntax
 
 /**
   * Implements internal options that the launcher may use when running another
@@ -28,9 +29,18 @@ import org.enso.launcher.OS
   *    launcher attempts several retries, because it may take some time for the
   *    executable to be unlocked (especially as on Windows software like an
   *    antivirus may block it for some more time after terminating).
+  * 2. Finish Uninstall
+  *    After uninstalling the distribution, we need to remove the executable,
+  *    but for the same reasons as above, we need a workaround. The uninstaller
+  *    creates a copy of itself in a temporary directory (which will be removed
+  *    when the system removes temporary files) and uses it to remove the
+  *    original binary. It then can also remove the (now empty) installation
+  *    directory if necessary.
   */
 object InternalOpts {
-  private val REMOVE_OLD_EXECUTABLE = "internal-remove-old-executable"
+  private val REMOVE_OLD_EXECUTABLE   = "internal-remove-old-executable"
+  private val FINISH_UNINSTALL        = "internal-finish-uninstall"
+  private val FINISH_UNINSTALL_PARENT = "internal-finish-uninstall-parent"
 
   /**
     * Additional top level options that are internal to the launcher and should
@@ -48,11 +58,38 @@ object InternalOpts {
       )
       .hidden
 
-    removeOldExecutableOpt map {
-      case Some(oldExecutablePath) =>
-        removeOldExecutable(oldExecutablePath)
-        sys.exit(0)
-      case None =>
+    val finishUninstallOpt = Opts
+      .optionalParameter[Path](
+        FINISH_UNINSTALL,
+        "PATH",
+        "Removes the old executable."
+      )
+      .hidden
+    val finishUninstallParentOpt = Opts
+      .optionalParameter[Path](
+        FINISH_UNINSTALL_PARENT,
+        "PATH",
+        s"Removes the possible parent directories of the old executable. " +
+        s"To be used only in conjunction with $FINISH_UNINSTALL. Has no " +
+        s"effect if used without that option."
+      )
+      .hidden
+
+    (
+      removeOldExecutableOpt,
+      finishUninstallOpt,
+      finishUninstallParentOpt
+    ) mapN {
+      (removeOldExecutableOpt, finishUninstallOpt, finishUninstallParentOpt) =>
+        removeOldExecutableOpt.foreach { oldExecutablePath =>
+          removeOldExecutable(oldExecutablePath)
+          sys.exit(0)
+        }
+
+        finishUninstallOpt.foreach { executablePath =>
+          finishUninstall(executablePath, finishUninstallParentOpt)
+          sys.exit(0)
+        }
     }
   }
 
@@ -63,6 +100,10 @@ object InternalOpts {
   def runWithNewLauncher(pathToNewLauncher: Path): Runner =
     new Runner(pathToNewLauncher)
 
+  /**
+    * A helper class used for running the workarounds using another launcher
+    * executable.
+    */
   class Runner private[InternalOpts] (pathToNewLauncher: Path) {
 
     /**
@@ -80,38 +121,89 @@ object InternalOpts {
       )
       runDetachedAndExit(command)
     }
+
+    /**
+      * Tells the temporary launcher to remove the original launcher executable
+      * and possibly its parent directory.
+      *
+      * The parent directory is removed if it is empty or only contains an empty
+      * `bin` directory. This is used for cases when the executable is inside of
+      * the data directory and the data directory cannot be fully removed before
+      * the executable has been removed.
+      *
+      * @param executablePath path to the old executable
+      * @param parentToRemove path to the parent directory
+      */
+    def finishUninstall(
+      executablePath: Path,
+      parentToRemove: Option[Path]
+    ): Nothing = {
+      val parentParam = parentToRemove.map(parent =>
+        Seq(s"--$FINISH_UNINSTALL_PARENT", parent.toAbsolutePath.toString)
+      )
+      val command = Seq(
+          pathToNewLauncher.toAbsolutePath.toString,
+          s"--$FINISH_UNINSTALL",
+          executablePath.toAbsolutePath.toString
+        ) ++ parentParam.getOrElse(Seq())
+      runDetachedAndExit(command)
+    }
   }
 
-  private def removeOldExecutable(oldExecutablePath: Path): Unit = {
-    val retryBaseAmount = 30
-    @scala.annotation.tailrec
-    def tryDeleting(retries: Int): Unit = {
-      try {
-        Files.delete(oldExecutablePath)
-      } catch {
-        case _: NoSuchFileException =>
-        case e: IOException =>
-          if (retries == retryBaseAmount) {
-            System.err.println(
-              s"Could not remove $oldExecutablePath, will retry several " +
-              s"times for 15s..."
-            )
-          }
+  private val retryBaseAmount = 30
 
-          if (retries > 0) {
-            Thread.sleep(500)
-            tryDeleting(retries - 1)
-          } else {
-            e.printStackTrace()
-            System.err.println(
-              s"Cannot delete old executable at $oldExecutablePath after " +
-              s"multiple retries. Please try removing it manually."
-            )
-          }
-      }
+  /**
+    * Tries to remove the file at `oldExecutablePath`, retrying several times if
+    * needed.
+    *
+    * On failure retries every 0.5s for 15s in total. That retry mechanism is in
+    * place, because a running executable cannot be removed and it may take some
+    * time for the process to fully terminate (theoretically this time can be
+    * extended indefinitely, for example if anti-virus software blocks the
+    * executable for scanning, so this may still fail).
+    */
+  @scala.annotation.tailrec
+  private def tryDeleting(oldExecutablePath: Path, retries: Int = 30): Unit = {
+    try {
+      Files.delete(oldExecutablePath)
+    } catch {
+      case _: NoSuchFileException =>
+      case e: IOException =>
+        def firstTime = retries == retryBaseAmount
+        if (firstTime) {
+          System.err.println(
+            s"Could not remove $oldExecutablePath, will retry several " +
+            s"times for 15s..."
+          )
+        }
+
+        if (retries > 0) {
+          Thread.sleep(500)
+          tryDeleting(oldExecutablePath, retries - 1)
+        } else {
+          e.printStackTrace()
+          System.err.println(
+            s"Cannot delete old executable at $oldExecutablePath after " +
+            s"multiple retries. Please try removing it manually."
+          )
+        }
     }
+  }
 
-    tryDeleting(retryBaseAmount)
+  private def removeOldExecutable(oldExecutablePath: Path): Unit =
+    tryDeleting(oldExecutablePath)
+
+  private def finishUninstall(
+    executablePath: Path,
+    parentToRemove: Option[Path]
+  ): Unit = {
+    tryDeleting(executablePath)
+    parentToRemove.foreach { parent =>
+      val bin = parent / "bin"
+      if (Files.exists(bin))
+        FileSystem.removeDirectoryIfEmpty(bin)
+      FileSystem.removeDirectoryIfEmpty(parent)
+    }
   }
 
   private def runDetachedAndExit(command: Seq[String]): Nothing = {

engine/launcher/src/main/scala/org/enso/launcher/cli/Main.scala

@@ -12,7 +12,8 @@ import org.enso.launcher.components.runner.LanguageServerOptions
 import org.enso.launcher.installation.DistributionInstaller.BundleAction
 import org.enso.launcher.installation.{
   DistributionInstaller,
-  DistributionManager
+  DistributionManager,
+  DistributionUninstaller
 }
 import org.enso.launcher.{Launcher, Logger}
 
@@ -251,7 +252,11 @@ object Main {
     }
 
   private def installEngineCommand: Subcommand[Config => Unit] =
-    Subcommand("engine") {
+    Subcommand(
+      "engine",
+      "Installs the specified engine version, defaulting to the latest if " +
+      "unspecified."
+    ) {
       val version = Opts.optionalArgument[SemVer](
         "VERSION",
         "VERSION specifies the engine version to install. If not provided, the" +
@@ -268,7 +273,10 @@ object Main {
     }
 
   private def installDistributionCommand: Subcommand[Config => Unit] =
-    Subcommand("distribution") {
+    Subcommand(
+      "distribution",
+      "Installs Enso on the system, deactivating portable mode."
+    ) {
 
       implicit val bundleActionParser: Argument[BundleAction] = {
         case "move"   => DistributionInstaller.MoveBundles.asRight
@@ -319,7 +327,11 @@ object Main {
     }
 
   private def uninstallEngineCommand: Subcommand[Config => Unit] =
-    Subcommand("engine") {
+    Subcommand(
+      "engine",
+      "Uninstalls the provided engine version. If the corresponding runtime " +
+      "is not used by any remaining engine installations, it is also removed."
+    ) {
       val version = Opts.positionalArgument[SemVer]("VERSION")
       version map { version => (config: Config) =>
         Launcher(config).uninstallEngine(version)
@@ -327,10 +339,18 @@ object Main {
     }
 
   private def uninstallDistributionCommand: Subcommand[Config => Unit] =
-    Subcommand("distribution") {
-      Opts.pure(()) map { (_: Unit) => (_: Config) =>
-        Logger.error("Not implemented yet.")
-        sys.exit(1)
+    Subcommand(
+      "distribution",
+      "Uninstalls whole Enso distribution and all components managed by " +
+      "it. If `auto-confirm` is set, it will not attempt to remove the " +
+      "ENSO_DATA_DIRECTORY and ENSO_CONFIG_DIRECTORY if they contain any " +
+      "unexpected files."
+    ) {
+      Opts.pure(()) map { (_: Unit) => (config: Config) =>
+        new DistributionUninstaller(
+          DistributionManager,
+          autoConfirm = config.autoConfirm
+        ).uninstall()
       }
     }
 

engine/launcher/src/main/scala/org/enso/launcher/installation/DistributionUninstaller.scala

@@ -0,0 +1,281 @@
+package org.enso.launcher.installation
+
+import java.nio.file.{Files, Path}
+
+import org.apache.commons.io.FileUtils
+import org.enso.cli.CLIOutput
+import org.enso.launcher.FileSystem.PathSyntax
+import org.enso.launcher.cli.InternalOpts
+import org.enso.launcher.{FileSystem, GlobalConfigurationManager, Logger, OS}
+
+/**
+  * Allows to [[uninstall]] an installed distribution.
+  *
+  * @param manager a distribution manager instance which defines locations for
+  *                the distribution that will be uninstalled
+  * @param autoConfirm if set to true, the uninstaller will use defaults
+  *                    instead of asking questions
+  */
+class DistributionUninstaller(
+  manager: DistributionManager,
+  autoConfirm: Boolean
+) {
+
+  /**
+    * Uninstalls a locally installed (non-portable) distribution.
+    *
+    * Removes the launcher executable and the ENSO_DATA_DIRECTORY and
+    * ENSO_CONFIG_DIRECTORY directories (unless they contain unexpected files).
+    * If unexpected files are encountered and [[autoConfirm]] is set, the files
+    * are preserved and the directories are not removed (but the expected
+    * contents are cleaned anyway), otherwise the program asks if the unexpected
+    * files should be removed.
+    */
+  def uninstall(): Unit = {
+    checkPortable()
+    askConfirmation()
+    if (OS.isWindows) uninstallWindows()
+    else uninstallUNIX()
+  }
+
+  /**
+    * Uninstall strategy for OSes that can remove running executables.
+    *
+    * Simply removes each component, starting with the ones that can potentially
+    * be nested (as config and the binary can be inside of the data directory
+    * if the user wishes so).
+    */
+  private def uninstallUNIX(): Unit = {
+    uninstallConfig()
+    uninstallExecutableUNIX()
+    uninstallDataContents(deferDataRootRemoval = false)
+    Logger.info("Successfully uninstalled the distribution.")
+  }
+
+  /**
+    * Uninstall strategy for Windows, where it is not possible to remove a
+    * running executable.
+    *
+    * The executable has to be removed last as the program must terminate to do
+    * so. If the executable is inside of the data directory, the directory is
+    * cleaned, but its removal is deferred and it will be removed just after the
+    * executable at the end.
+    */
+  private def uninstallWindows(): Unit = {
+    val deferRootRemoval = isBinaryInsideData
+    uninstallConfig()
+    uninstallDataContents(deferRootRemoval)
+    Logger.info(
+      "Successfully uninstalled the distribution but for the launcher " +
+      "executable. It will be removed in a moment after this program " +
+      "terminates."
+    )
+    uninstallExecutableWindows(
+      if (deferRootRemoval) Some(manager.paths.dataRoot) else None
+    )
+  }
+
+  /**
+    * Checks if the launcher is running in portable mode and terminates
+    * execution if it does.
+    *
+    * It prints an explanation that uninstall can only be used with non-portable
+    * mode and a tip on how the portable distribution can be easily removed
+    * manually.
+    */
+  private def checkPortable(): Unit = {
+    if (manager.isRunningPortable) {
+      Logger.warn(
+        "The Enso distribution you are currently running is in portable " +
+        "mode, so it cannot be uninstalled."
+      )
+      Logger.info(
+        s"If you still want to remove it, you can just remove the " +
+        s"`${manager.paths.dataRoot}` directory."
+      )
+      sys.exit(1)
+    }
+  }
+
+  /**
+    * Prints an explanation of what will be uninstalled and which directories
+    * will be removed and asks the user if they want to proceed.
+    */
+  private def askConfirmation(): Unit = {
+    Logger.info(
+      s"Uninstalling this distribution will remove the launcher located at " +
+      s"`${manager.env.getPathToRunningExecutable}`, all engine and runtime " +
+      s"components and configuration managed by this distribution."
+    )
+    Logger.info(
+      s"ENSO_DATA_DIRECTORY (${manager.paths.dataRoot}) and " +
+      s"ENSO_CONFIG_DIRECTORY (${manager.paths.config}) will be removed " +
+      s"unless they contain unexpected files."
+    )
+    if (!autoConfirm) {
+      val proceed =
+        CLIOutput.askConfirmation("Do you want to proceed?", yesDefault = true)
+      if (!proceed) {
+        Logger.warn("Installation has been cancelled on user request.")
+        sys.exit(1)
+      }
+    }
+  }
+
+  /**
+    * True if the currently running executable is inside of the data root.
+    *
+    * This is checked, because on Windows this will make removing data root more
+    * complicated.
+    */
+  private def isBinaryInsideData: Boolean = {
+    val binaryPath =
+      manager.env.getPathToRunningExecutable.toAbsolutePath.normalize
+    val dataPath = manager.paths.dataRoot.toAbsolutePath.normalize
+    binaryPath.startsWith(dataPath)
+  }
+
+  /**
+    * Removes the configuration file and the ENSO_CONFIG_DIRECTORY if it does
+    * not contain any other files (or if the user agreed to remove them too).
+    */
+  private def uninstallConfig(): Unit = {
+    FileSystem.removeFileIfExists(
+      manager.paths.config / GlobalConfigurationManager.globalConfigName
+    )
+    val remaining =
+      FileSystem.listDirectory(manager.paths.config).map(_.getFileName.toString)
+    handleRemainingFiles(
+      manager.LocallyInstalledDirectories.ENSO_CONFIG_DIRECTORY,
+      manager.paths.config,
+      remaining
+    )
+    FileSystem.removeDirectoryIfEmpty(manager.paths.config)
+  }
+
+  /**
+    * Files that are expected to be inside of the data root.
+    */
+  private val knownDataFiles = Seq("README.md", "NOTICE")
+
+  /**
+    * Directories that are expected to be inside of the data root.
+    */
+  private val knownDataDirectories = Seq("tmp", "components-licences", "config")
+
+  /**
+    * Removes all files contained in the ENSO_DATA_DIRECTORY and possibly the
+    * directory itself.
+    *
+    * If `deferDataRootRemoval` is set, the directory itself is not removed
+    * because removing the `bin` directory may block this action. Other files
+    * and directories are removed nonetheless,so only the `bin` directory and
+    * the root itself are removed at the end.
+    */
+  private def uninstallDataContents(deferDataRootRemoval: Boolean): Unit = {
+    FileSystem.removeDirectory(manager.paths.engines)
+    FileSystem.removeDirectory(manager.paths.runtimes)
+
+    val dataRoot = manager.paths.dataRoot
+    for (dirName <- knownDataDirectories) {
+      FileSystem.removeDirectoryIfExists(dataRoot / dirName)
+    }
+    for (fileName <- knownDataFiles) {
+      FileSystem.removeFileIfExists(dataRoot / fileName)
+    }
+
+    if (!deferDataRootRemoval) {
+      val nestedBinDirectory = dataRoot / "bin"
+      if (Files.exists(nestedBinDirectory))
+        FileSystem.removeDirectoryIfEmpty(nestedBinDirectory)
+    }
+
+    val ignoredFiles = if (deferDataRootRemoval) Set("bin") else Set()
+    val remainingFiles = FileSystem
+        .listDirectory(dataRoot)
+        .map(_.getFileName.toString)
+        .toSet -- ignoredFiles
+    if (remainingFiles.nonEmpty) {
+      handleRemainingFiles(
+        manager.LocallyInstalledDirectories.ENSO_DATA_DIRECTORY,
+        dataRoot.toAbsolutePath.normalize,
+        remainingFiles.toSeq
+      )
+    }
+
+    if (!deferDataRootRemoval) {
+      FileSystem.removeDirectoryIfEmpty(dataRoot)
+    }
+  }
+
+  /**
+    * Common logic for handling unexpected files in ENSO_DATA_DIRECTORY and
+    * ENSO_CONFIG_DIRECTORY.
+    *
+    * It asks the user if they want to remove these files unless `auto-confirm`
+    * is set, in which case it just prints a warning.
+    *
+    * @param directoryName name of the directory
+    * @param path path to the directory
+    * @param remainingFiles sequence of filenames that are present in that
+    *                       directory but are not expected
+    */
+  private def handleRemainingFiles(
+    directoryName: String,
+    path: Path,
+    remainingFiles: Seq[String]
+  ): Unit =
+    if (remainingFiles.nonEmpty) {
+      def remainingFilesList =
+        remainingFiles.map(fileName => s"`$fileName`").mkString(", ")
+      if (autoConfirm) {
+        Logger.warn(
+          s"$directoryName ($path) contains unexpected files: " +
+          s"$remainingFilesList, so it will not be removed."
+        )
+      } else {
+        Logger.warn(
+          s"$directoryName ($path) contains unexpected files: " +
+          s"$remainingFilesList."
+        )
+        def confirmation =
+          CLIOutput.askConfirmation(
+            s"Do you want to remove the $directoryName containing these files?"
+          )
+        if (confirmation) {
+          for (fileName <- remainingFiles) {
+            FileUtils.forceDelete((path / fileName).toFile)
+          }
+        }
+      }
+    }
+
+  /**
+    * Uninstalls the executable on platforms that allow for removing running
+    * files.
+    *
+    * Simply removes the file.
+    */
+  private def uninstallExecutableUNIX(): Unit = {
+    FileSystem.removeFileIfExists(manager.env.getPathToRunningExecutable)
+  }
+
+  /**
+    * Uninstalls the executable on Windows where it is impossible to remove an
+    * executable that is running.
+    *
+    * Uses a workaround implemented in [[InternalOpts]]. Has to be run at the
+    * very end as it has to terminate the current executable.
+    */
+  private def uninstallExecutableWindows(
+    parentToRemove: Option[Path]
+  ): Nothing = {
+    val temporaryLauncher =
+      Files.createTempDirectory("enso-uninstall") / OS.executableName("enso")
+    val oldLauncher = manager.env.getPathToRunningExecutable
+    Files.copy(oldLauncher, temporaryLauncher)
+    InternalOpts
+      .runWithNewLauncher(temporaryLauncher)
+      .finishUninstall(oldLauncher, parentToRemove)
+  }
+}

engine/launcher/src/test/scala/org/enso/launcher/NativeTest.scala

@@ -37,8 +37,10 @@ trait NativeTest extends AnyWordSpec with Matchers with TimeLimitedTests {
     override def apply(left: RunResult): MatchResult =
       MatchResult(
         left.exitCode == 0,
-        s"Run did not exit with success but exit with code ${left.exitCode}.",
-        s"Run did not fail as expected."
+        s"Run did not exit with success but exit with code ${left.exitCode}.\n" +
+        s"Its stderr was: ```${left.stderr}```.\n" +
+        s"And stdout was: ```${left.stdout}```.",
+        s"Run did not fail as expected. It printed ```${left.stdout}```."
       )
   }
 

engine/launcher/src/test/scala/org/enso/launcher/installation/InstallerSpec.scala

@@ -17,7 +17,7 @@ class InstallerSpec extends NativeTest with WithTemporaryDirectory {
     FileSystem.writeTextFile(portableRoot / ".enso.portable", "mark")
     Files.createDirectories(portableRoot / "config")
     FileSystem.writeTextFile(
-      portableRoot / "config" / "global-config.yml",
+      portableRoot / "config" / "global-config.yaml",
       "what: ever"
     )
   }
@@ -80,7 +80,7 @@ class InstallerSpec extends NativeTest with WithTemporaryDirectory {
         "The installed file should be executable."
       )
 
-      val config = installedRoot / "config" / "global-config.yml"
+      val config = installedRoot / "config" / "global-config.yaml"
       config.toFile should exist
       readFileContent(config).stripTrailing() shouldEqual "what: ever"
 

engine/launcher/src/test/scala/org/enso/launcher/installation/UninstallerSpec.scala

@@ -0,0 +1,116 @@
+package org.enso.launcher.installation
+
+import java.nio.file.{Files, Path}
+
+import org.enso.launcher.FileSystem.PathSyntax
+import org.enso.launcher.{FileSystem, NativeTest, OS, WithTemporaryDirectory}
+
+class UninstallerSpec extends NativeTest with WithTemporaryDirectory {
+  def installedRoot: Path = getTestDirectory / "installed"
+
+  /**
+    * Prepares an installed distribution for the purposes of testing
+    * uninstallation.
+    *
+    * @param everythingInsideData if true, config and binary directory are put
+    *                             inside the data root
+    * @return returns the path to the created launcher and a mapping of
+    *         environment overrides that need to be used for it to use the
+    *         correct installation directory
+    */
+  def prepareInstalledDistribution(
+    everythingInsideData: Boolean = false
+  ): (Path, Map[String, String]) = {
+    val binDirectory =
+      if (everythingInsideData) installedRoot / "bin" else getTestDirectory
+    val configDirectory =
+      if (everythingInsideData) installedRoot / "config"
+      else getTestDirectory / "enso-config"
+    val dataDirectory    = installedRoot
+    val portableLauncher = binDirectory / OS.executableName("enso")
+    copyLauncherTo(portableLauncher)
+    Files.createDirectories(dataDirectory / "dist")
+    Files.createDirectories(configDirectory)
+    FileSystem.writeTextFile(
+      configDirectory / "global-config.yaml",
+      "what: ever"
+    )
+    FileSystem.writeTextFile(dataDirectory / "README.md", "content")
+    Files.createDirectories(dataDirectory / "tmp")
+
+    val env = Map(
+      "ENSO_DATA_DIRECTORY"   -> dataDirectory.toAbsolutePath.normalize.toString,
+      "ENSO_BIN_DIRECTORY"    -> binDirectory.toAbsolutePath.normalize.toString,
+      "ENSO_CONFIG_DIRECTORY" -> configDirectory.toAbsolutePath.normalize.toString
+    )
+    (portableLauncher, env)
+  }
+
+  "enso uninstall distribution" should {
+    "uninstall a simple distribution" in {
+      val (launcher, env) = prepareInstalledDistribution()
+
+      runLauncherAt(
+        launcher,
+        Seq("--auto-confirm", "uninstall", "distribution"),
+        env
+      ) should returnSuccess
+
+      assert(Files.notExists(installedRoot), "Should remove the data root.")
+      assert(
+        Files.notExists(getTestDirectory / "enso-config"),
+        "Should remove the configuration directory."
+      )
+      assert(Files.notExists(launcher), "Should remove the executable.")
+    }
+
+    "uninstall a distribution with config and bin inside of data" in {
+      val (launcher, env) =
+        prepareInstalledDistribution(everythingInsideData = true)
+
+      runLauncherAt(
+        launcher,
+        Seq("--auto-confirm", "uninstall", "distribution"),
+        env
+      ) should returnSuccess
+
+      assert(Files.notExists(installedRoot), "Should remove the data root.")
+    }
+
+    "not remove unknown files by default when uninstalling" in {
+      val (launcher, env) = prepareInstalledDistribution()
+      val configFile      = getTestDirectory / "enso-config" / "unknown-file"
+      FileSystem.writeTextFile(configFile, "mark")
+      val dataFile = installedRoot / "unknown-file2"
+      FileSystem.writeTextFile(dataFile, "mark")
+
+      runLauncherAt(
+        launcher,
+        Seq("--auto-confirm", "uninstall", "distribution"),
+        env
+      ) should returnSuccess
+
+      assert(
+        Files.exists(installedRoot),
+        "Should not remove the data root with extra files."
+      )
+      assert(
+        Files.exists(getTestDirectory / "enso-config"),
+        "Should not remove the configuration root with extra files."
+      )
+      assert(Files.exists(dataFile), "Should not remove unknown files.")
+      assert(Files.exists(configFile), "Should not remove unknown files.")
+      assert(
+        Files.notExists(
+          getTestDirectory / "enso-config" / "global-config.yaml"
+        ),
+        "But the known ones should be removed."
+      )
+      assert(
+        Files.notExists(installedRoot / "dist"),
+        "But the known ones should be removed."
+      )
+      assert(Files.notExists(launcher), "Should remove the executable.")
+    }
+  }
+}

lib/scala/cli/src/main/scala/org/enso/cli/Command.scala

@@ -38,10 +38,11 @@ case class Command[A](
   * [[Opts.subcommands]].
   *
   * @param name name of the subcommand
+  * @param comment a help comment displayed in the commands help text
   * @param opts parsing logic for the subcommand's options
   * @tparam A type returned by the command
   */
-case class Subcommand[A](name: String)(val opts: Opts[A])
+case class Subcommand[A](name: String, comment: String)(val opts: Opts[A])
 
 object Command {
 

lib/scala/cli/src/main/scala/org/enso/cli/Opts.scala

@@ -202,11 +202,10 @@ trait Opts[A] {
     *                      entries are commands/subcommands.
     */
   def help(commandPrefix: Seq[String]): String = {
-    val tableDivider = "\t"
-    val prefix       = commandPrefix.mkString(" ")
-    val usages       = commandLines().map(s"$prefix$tableDivider" + _)
-    val firstLine    = "Usage: "
-    val padding      = " " * firstLine.length
+    val prefix    = commandPrefix.mkString(" ")
+    val usages    = commandLines().map(s"$prefix\t" + _)
+    val firstLine = "Usage: "
+    val padding   = " " * firstLine.length
     val usage =
       firstLine + usages.head +
       usages.tail.map("\n" + padding + _).mkString + "\n"

lib/scala/cli/src/main/scala/org/enso/cli/internal/SubcommandOpt.scala

@@ -87,8 +87,13 @@ class SubcommandOpt[A](subcommands: NonEmptyList[Subcommand[A]])
     subcommands.toList.flatMap(_.opts.additionalHelp()).distinct
 
   override def commandLines(): NonEmptyList[String] = {
-    def prefixedCommandLines(command: Subcommand[_]): NonEmptyList[String] =
-      command.opts.commandLines().map(command.name + " " + _)
+    def prefixedCommandLines(command: Subcommand[_]): NonEmptyList[String] = {
+      val prefix = command.name + " "
+      val suffix = s"\n\t${command.comment}"
+      command.opts
+        .commandLines()
+        .map(commandLine => prefix + commandLine + suffix)
+    }
 
     subcommands.flatMap(prefixedCommandLines)
   }

lib/scala/cli/src/test/scala/org/enso/cli/OptsSpec.scala

@@ -242,10 +242,10 @@ class OptsSpec
 
   "subcommands" should {
     val opt = Opts.subcommands(
-      Subcommand("cmd1") {
+      Subcommand("cmd1", "cmd1 help") {
         Opts.flag("flag1", "", showInUsage = true).map((1, _))
       },
-      Subcommand("cmd2") {
+      Subcommand("cmd2", "cmd1 help") {
         Opts.flag("flag2", "", showInUsage = true).map((2, _))
       }
     )

project/EnvironmentCheck.scala

@@ -24,7 +24,7 @@ object EnvironmentCheck {
     val javaSpecificationVersion =
       System.getProperty("java.vm.specification.version")
     val graalVersion =
-      System.getProperty("org.graalvm.version")
+      System.getProperty("java.vendor.version")
 
     val graalOk =
       if (graalVersion == null) {
@@ -70,10 +70,11 @@ object EnvironmentCheck {
     try {
       val versionStr = cmd.!!.trim.substring(6)
 
-      if (versionStr != expectedVersion) log.error(
-        s"Rust version mismatch. $expectedVersion is expected, " +
+      if (versionStr != expectedVersion)
+        log.error(
+          s"Rust version mismatch. $expectedVersion is expected, " +
           s"but it seems $versionStr is installed."
-      )
+        )
       versionStr == expectedVersion
     } catch {
       case _ @(_: RuntimeException | _: IOException) =>