Update Kotlin to 2.0 (#900)

- update Kotlin from 1.7.10 to 2.0.21
  - Kotlin 1.6 dependencies in Gradle lock files are expected because kotlinc,
    which is also used by some tests, internally uses some 1.6 dependencies
    for backwards compatibility reasons.
- update kotlinx-html and kotlinx-serialization
- adapt Kotlin code where necessary
- use Kotlin stdlib Path APIs where possible
- fix IntelliJ Kotlin inspection warnings
- reformat code with `./gradlew spotlessApply`
  - ktfmt adds lots of trailing commas
- Add workaround to fix IntelliJ "unresolved reference" errors

pkl-cli/src/main/kotlin/org/pkl/cli/CliEvaluator.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,11 +21,11 @@ import java.io.Writer
 import java.net.URI
 import java.nio.file.Path
 import java.nio.file.StandardOpenOption
+import kotlin.io.path.createParentDirectories
 import kotlin.io.path.exists
 import kotlin.io.path.isDirectory
 import org.pkl.commons.cli.CliCommand
 import org.pkl.commons.cli.CliException
-import org.pkl.commons.createParentDirectories
 import org.pkl.commons.currentWorkingDir
 import org.pkl.commons.writeString
 import org.pkl.core.Closeables
@@ -165,13 +165,13 @@ constructor(
                 options.moduleOutputSeparator + '\n',
                 Charsets.UTF_8,
                 StandardOpenOption.WRITE,
-                StandardOpenOption.APPEND
+                StandardOpenOption.APPEND,
               )
               outputFile.writeString(
                 output,
                 Charsets.UTF_8,
                 StandardOpenOption.WRITE,
-                StandardOpenOption.APPEND
+                StandardOpenOption.APPEND,
               )
             }
           }

pkl-cli/src/main/kotlin/org/pkl/cli/CliEvaluatorOptions.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -80,6 +80,6 @@ data class CliEvaluatorOptions(
 ) {
 
   companion object {
-    val defaults = CliEvaluatorOptions(CliBaseOptions())
+    val defaults: CliEvaluatorOptions = CliEvaluatorOptions(CliBaseOptions())
   }
 }

pkl-cli/src/main/kotlin/org/pkl/cli/CliImportAnalyzer.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,8 @@
 package org.pkl.cli
 
 import java.io.Writer
+import kotlin.io.path.createParentDirectories
 import org.pkl.commons.cli.CliCommand
-import org.pkl.commons.createParentDirectories
 import org.pkl.commons.writeString
 import org.pkl.core.Closeables
 import org.pkl.core.ModuleSource
@@ -26,7 +26,7 @@ class CliImportAnalyzer
 @JvmOverloads
 constructor(
   private val options: CliImportAnalyzerOptions,
-  private val consoleWriter: Writer = System.out.writer()
+  private val consoleWriter: Writer = System.out.writer(),
 ) : CliCommand(options.base) {
 
   override fun doRun() {

pkl-cli/src/main/kotlin/org/pkl/cli/CliServer.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,7 +22,7 @@ import org.pkl.core.messaging.ProtocolException
 import org.pkl.server.Server
 
 class CliServer(options: CliBaseOptions) : CliCommand(options) {
-  override fun doRun() =
+  override fun doRun(): Unit =
     try {
       val server = Server.stream(System.`in`, System.out)
       server.use { it.start() }

pkl-cli/src/main/kotlin/org/pkl/cli/repl/ReplCommands.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,7 +20,7 @@ private val cmdRegex = Regex(":(\\p{Alpha}*)(\\p{Space}*)(.*)", RegexOption.DOT_
 internal fun getMatchingCommands(input: String): List<ParsedCommand> {
   val match = cmdRegex.matchEntire(input) ?: return listOf()
   val (cmd, ws, arg) = match.destructured
-  return Command.values()
+  return Command.entries
     .filter { it.toString().lowercase().startsWith(cmd) }
     .map { ParsedCommand(it, cmd, ws, arg) }
 }
@@ -29,7 +29,7 @@ internal data class ParsedCommand(
   val type: Command,
   val cmd: String,
   val ws: String,
-  val arg: String
+  val arg: String,
 )
 
 internal enum class Command {

pkl-cli/src/main/kotlin/org/pkl/cli/repl/ReplCompleters.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -40,7 +40,7 @@ internal abstract class JLineFileNameCompleter : Completer {
   override fun complete(
     reader: LineReader,
     commandLine: ParsedLine,
-    candidates: MutableList<Candidate>
+    candidates: MutableList<Candidate>,
   ) {
     val buffer = commandLine.word().substring(0, commandLine.wordCursor())
     val current: Path
@@ -78,7 +78,7 @@ internal abstract class JLineFileNameCompleter : Completer {
                     null,
                     if (reader.isSet(LineReader.Option.AUTO_REMOVE_SLASH)) sep else null,
                     null,
-                    false
+                    false,
                   )
                 )
               } else {
@@ -90,7 +90,7 @@ internal abstract class JLineFileNameCompleter : Completer {
                     null,
                     null,
                     null,
-                    true
+                    true,
                   )
                 )
               }
@@ -122,7 +122,7 @@ internal abstract class JLineFileNameCompleter : Completer {
     terminal: Terminal,
     path: Path,
     resolver: StyleResolver,
-    separator: String
+    separator: String,
   ): String {
     val builder = AttributedStringBuilder()
     val name = path.fileName.toString()
@@ -162,7 +162,7 @@ internal class FileCompleter(override val userDir: Path) : JLineFileNameComplete
   override fun complete(
     reader: LineReader,
     commandLine: ParsedLine,
-    candidates: MutableList<Candidate>
+    candidates: MutableList<Candidate>,
   ) {
     val loadCmd =
       getMatchingCommands(commandLine.line()).find { it.type == Command.Load && it.ws.isNotEmpty() }
@@ -174,7 +174,7 @@ internal class FileCompleter(override val userDir: Path) : JLineFileNameComplete
 
 internal object CommandCompleter : Completer {
   private val commandCandidates: List<Candidate> =
-    Command.values().map { Candidate(":" + it.toString().lowercase()) }
+    Command.entries.map { Candidate(":" + it.toString().lowercase()) }
 
   override fun complete(reader: LineReader, line: ParsedLine, candidates: MutableList<Candidate>) {
     if (line.wordIndex() == 0) candidates.addAll(commandCandidates)