Adopt Kotlin collection literals across src and test

build.gradle.kts

@@ -6,7 +6,6 @@ import dev.detekt.gradle.Detekt
 import dev.detekt.gradle.extensions.DetektExtension
 import org.gradle.api.tasks.testing.logging.TestExceptionFormat
 import org.gradle.api.tasks.testing.logging.TestLogEvent
-import org.gradle.kotlin.dsl.withType
 
 plugins {
   alias(libs.plugins.kotlin.jvm)
@@ -46,12 +45,13 @@ dependencies {
   kover(project(kotestModule))
 }
 
-dokka {
-  moduleName.set("ReadingBat")
-  pluginsConfiguration.html {
-    homepageLink.set(repoUrl)
-    footerMessage.set(projectName)
-  }
+// Dokka config is root-level (aggregate docs); the plugin is applied via the plugins {} block
+// above. It can't go in allprojects {} — subprojects don't have the Dokka plugin applied until
+// the subprojects {} block below runs, so the `dokka` extension wouldn't exist yet there.
+configureDokka()
+
+allprojects {
+  configureVersions()
 }
 
 subprojects {
@@ -68,7 +68,6 @@ subprojects {
   configureKotlinter()
   configureDetekt()
   configureSecrets()
-  configureVersions()
 }
 
 fun Project.configureKotlin() {
@@ -83,6 +82,15 @@ fun Project.configureKotlin() {
   kotlin {
     jvmToolchain(jvmTargetVersion.toInt())
 
+    // Collection literals (`val x: List<Int> = [1, 2, 3]`) are an experimental Kotlin 2.4
+    // feature gated behind this flag. Removing it breaks every `[...]` literal in the
+    // sources. Note this flag applies to project sources only -- it is NOT in effect for
+    // the JSR-223 script engine that evaluates the content DSL at runtime, so DSL content
+    // files must keep using listOf()/mutableListOf().
+    compilerOptions {
+      freeCompilerArgs.add("-Xcollection-literals")
+    }
+
     sourceSets.all {
       listOf(
         "kotlin.ExperimentalStdlibApi",
@@ -202,6 +210,16 @@ fun Project.configureTesting() {
   }
 }
 
+fun Project.configureDokka() {
+  dokka {
+    moduleName.set("ReadingBat")
+    pluginsConfiguration.html {
+      homepageLink.set(repoUrl)
+      footerMessage.set(projectName)
+    }
+  }
+}
+
 fun Project.configureVersions() {
   // A pre-release qualifier is a `.` or `-` delimiter followed by a known unstable
   // keyword. `m\d` matches milestones (`-M1`/`.M2`) without catching stable classifiers

gradle/libs.versions.toml

@@ -6,37 +6,37 @@ jvm = "17"
 # Plugin versions
 buildconfig = "6.0.10"
 detekt = "2.0.0-alpha.5"
-kotlin = "2.4.0"
-kotlinter = "5.5.0"
-kover = "0.9.8"
+kotlin = "2.4.10"
+kotlinter = "5.6.0"
+kover = "0.9.9"
 dokka = "2.2.0"
 maven-publish = "0.37.0"
 versions = "0.54.0"
 
 # Library versions
-cloud = "1.28.6"
+cloud = "1.29.0"
 commons = "1.15.0"
 exposed = "1.3.1"
 flexmark = "0.64.8"
-flyway = "12.11.0"
+flyway = "13.0.0"
 github-api = "1.330"
 hikari = "7.1.0"
 java-scriptengine = "2.0.0"
 khealth = "3.0.1"
-kotest = "6.2.2"
+kotest = "6.2.3"
 ktor = "3.5.1"
 logback = "1.5.38"
 logging = "7.0.12"
 pgjdbc = "0.8.9"
 playwright = "1.61.0"
 postgres = "42.7.13"
 prometheus = "0.16.0"
-prometheus-proxy = "3.2.0"
+prometheus-proxy = "4.0.0"
 python = "2.7.4"
 resend = "4.13.0"
 serialization = "1.11.0"
 testcontainers = "1.21.4"
-utils = "3.1.0"
+utils = "3.2.1"
 
 [libraries]
 # Serialization

readingbat-core/src/main/kotlin/com/readingbat/common/FunctionInfo.kt

@@ -289,7 +289,7 @@ class FunctionInfo(
      */
     internal fun splitTopLevelCommas(csv: String): List<String> {
       if (csv.isBlank()) return emptyList()
-      val elements = mutableListOf<String>()
+      val elements: MutableList<String> = []
       val current = StringBuilder()
       var quoteChar: Char? = null
       for (c in csv) {

readingbat-core/src/main/kotlin/com/readingbat/common/Metrics.kt

@@ -199,80 +199,80 @@ class Metrics {
     SamplerGaugeCollector(
       "request_timing_map_size",
       "Request timing map size",
-      labelNames = listOf(AGENT_ID),
-      labelValues = listOf(agentLaunchId()),
+      labelNames = [AGENT_ID],
+      labelValues = [agentLaunchId()],
       data = { requestTimingMap.size.toDouble() },
     )
 
     SamplerGaugeCollector(
       "geo_map_size",
       "IP Geo map size",
-      labelNames = listOf(AGENT_ID),
-      labelValues = listOf(agentLaunchId()),
+      labelNames = [AGENT_ID],
+      labelValues = [agentLaunchId()],
       data = { geoInfoMap.size.toDouble() },
     )
 
     SamplerGaugeCollector(
       "content_map_size",
       "Content map size",
-      labelNames = listOf(AGENT_ID),
-      labelValues = listOf(agentLaunchId()),
+      labelNames = [AGENT_ID],
+      labelValues = [agentLaunchId()],
       data = { contentSource().contentMap.size.toDouble() },
     )
 
     SamplerGaugeCollector(
       "user_id_cache_size",
       "User ID cache size",
-      labelNames = listOf(AGENT_ID),
-      labelValues = listOf(agentLaunchId()),
+      labelNames = [AGENT_ID],
+      labelValues = [agentLaunchId()],
       data = { userIdCache.size.toDouble() },
     )
 
     SamplerGaugeCollector(
       "user_email_cache_size",
       "User email cache size size",
-      labelNames = listOf(AGENT_ID),
-      labelValues = listOf(agentLaunchId()),
+      labelNames = [AGENT_ID],
+      labelValues = [agentLaunchId()],
       data = { emailCache.size.toDouble() },
     )
 
     SamplerGaugeCollector(
       "sources_cache_size",
       "Sources cache size",
-      labelNames = listOf(AGENT_ID),
-      labelValues = listOf(agentLaunchId()),
+      labelNames = [AGENT_ID],
+      labelValues = [agentLaunchId()],
       data = { contentSource().functionInfoMap.size.toDouble() },
     )
 
     SamplerGaugeCollector(
       "websocket_connection_list_size",
       "Websocket connection list size",
-      labelNames = listOf(AGENT_ID),
-      labelValues = listOf(agentLaunchId()),
+      labelNames = [AGENT_ID],
+      labelValues = [agentLaunchId()],
       data = { answerWsConnections.size.toDouble() },
     )
 
     SamplerGaugeCollector(
       "active_users_1min_count",
       "Active users in last 1 min count",
-      labelNames = listOf(AGENT_ID),
-      labelValues = listOf(agentLaunchId()),
+      labelNames = [AGENT_ID],
+      labelValues = [agentLaunchId()],
       data = { activeSessions(1.minutes).toDouble() },
     )
 
     SamplerGaugeCollector(
       "active_users_15mins_count",
       "Active users in last 15 mins count",
-      labelNames = listOf(AGENT_ID),
-      labelValues = listOf(agentLaunchId()),
+      labelNames = [AGENT_ID],
+      labelValues = [agentLaunchId()],
       data = { activeSessions(15.minutes).toDouble() },
     )
 
     SamplerGaugeCollector(
       "active_users_60mins_count",
       "Active users in last 60 mins count",
-      labelNames = listOf(AGENT_ID),
-      labelValues = listOf(agentLaunchId()),
+      labelNames = [AGENT_ID],
+      labelValues = [agentLaunchId()],
       data = { activeSessions(1.hours).toDouble() },
     )
   }

readingbat-core/src/main/kotlin/com/readingbat/common/Property.kt

@@ -133,7 +133,7 @@ open class KtorProperty(
   companion object {
     private val logger = KotlinLogging.logger {}
     private val initialized = AtomicBoolean(false)
-    private val instances = mutableListOf<KtorProperty>()
+    private val instances: MutableList<KtorProperty> = []
     internal val configStore = java.util.concurrent.ConcurrentHashMap<String, String>()
 
     // Names of properties that have individually had a value assigned via setProperty. Lets the
@@ -466,7 +466,7 @@ sealed class Property(
 
     /** Returns the ordered list of properties that should be initialized at application startup. */
     fun initProperties() =
-      listOf(
+      [
         DSL_FILE_NAME,
         DSL_VARIABLE_NAME,
         PROXY_HOSTNAME,
@@ -503,6 +503,6 @@ sealed class Property(
         GOOGLE_OAUTH_CLIENT_ID,
         GOOGLE_OAUTH_CLIENT_SECRET,
         SESSION_SECRET,
-      )
+      ]
   }
 }

readingbat-core/src/main/kotlin/com/readingbat/dsl/ChallengeGroup.kt

@@ -67,7 +67,7 @@ class ChallengeGroup<T : Challenge>(
   internal val groupNameSuffix: GroupName,
 ) {
   /** The ordered list of challenges in this group. */
-  val challenges = mutableListOf<T>()
+  val challenges: MutableList<T> = []
 
   private val groupPrefix by lazy { pathOf(languageName, groupName) }
   private val srcPath get() = languageGroup.srcPath
@@ -149,7 +149,7 @@ class ChallengeGroup<T : Challenge>(
   var includeFilesWithType by IncludeFilesWithType(this, languageType)
 
   private class IncludeFiles<T : Challenge>(val group: ChallengeGroup<T>, val languageType: LanguageType) {
-    val includeList = mutableListOf<PatternReturnType>()
+    val includeList: MutableList<PatternReturnType> = []
 
     operator fun getValue(thisRef: Any?, property: KProperty<*>) = includeList.toString()
 
@@ -166,7 +166,7 @@ class ChallengeGroup<T : Challenge>(
   }
 
   private class IncludeFilesWithType<T : Challenge>(val group: ChallengeGroup<T>, val languageType: LanguageType) {
-    val includeList = mutableListOf<PatternReturnType>()
+    val includeList: MutableList<PatternReturnType> = []
 
     operator fun getValue(thisRef: Any?, property: KProperty<*>): PatternReturnType = PatternReturnType("", Runtime)
 

readingbat-core/src/main/kotlin/com/readingbat/dsl/ContentDsl.kt

@@ -198,22 +198,22 @@ internal fun evalContentDsl(
  */
 internal fun addImports(code: String, variableName: String): String {
   val classImports =
-    listOf(ReadingBatServer::class, GitHubContent::class)
+    [ReadingBatServer::class, GitHubContent::class]
       // .onEach { println("Checking for ${it.javaObjectType.name}") }
       .filter { code.contains("${it.javaObjectType.simpleName}(") }   // See if the class is referenced
       .map { "import ${it.javaObjectType.name}" }                           // Convert to import stmt
       .filterNot { code.contains(it) }                                      // Do not include if import already present
       .joinToString("\n")                                          // Turn into String
 
   val funcImports =
-    listOf(::readingBatContent)
+    [::readingBatContent]
       // .onEach { println("Checking for ${it.name}") }
       .filter { code.contains("${it.name}(") }  // See if the function is referenced
       .map { "import ${it.fqMethodName}" }            // Convert to import stmt
       .filterNot { code.contains(it) }                // Do not include is import already present
       .joinToString("\n")                    // Turn into String
 
-  val imports = listOf(classImports, funcImports).filter { it.isNotBlank() }.joinToString("\n")
+  val imports = [classImports, funcImports].filter { it.isNotBlank() }.joinToString("\n")
   return """
       $imports${if (imports.isBlank()) "" else "\n\n"}$code
       $variableName

readingbat-core/src/main/kotlin/com/readingbat/dsl/LanguageGroup.kt

@@ -48,7 +48,7 @@ class LanguageGroup<T : Challenge>(
   val contentRoot get() = languageType.contentRoot
 
   /** The ordered list of challenge groups in this language. */
-  val challengeGroups = mutableListOf<ChallengeGroup<T>>()
+  val challengeGroups: MutableList<ChallengeGroup<T>> = []
 
   /**
    * The content source for this language's challenge files. Inherits the parent

readingbat-core/src/main/kotlin/com/readingbat/dsl/LanguageType.kt

@@ -47,7 +47,7 @@ enum class LanguageType(val useDoubleQuotes: Boolean, val suffix: String, val sr
 
   companion object {
     val defaultLanguageType = Java
-    val languageTypeList = listOf(Java, Python, Kotlin)
+    val languageTypeList = [Java, Python, Kotlin]
 
     /** Returns all language types, optionally reordered to put [defaultLanguage] first. */
     fun languageTypes(defaultLanguage: LanguageType? = null): List<LanguageType> =

readingbat-core/src/main/kotlin/com/readingbat/dsl/ReadingBatContent.kt

@@ -77,7 +77,7 @@ import kotlin.time.measureTimedValue
 @ReadingBatDslMarker
 class ReadingBatContent {
   internal val timeStamp = LocalDateTime.now().format(DateTimeFormatter.ofPattern("M/d/y H:m:ss"))
-  private val languageList by lazy { listOf(java, python, kotlin) }
+  private val languageList by lazy { [java, python, kotlin] }
   private val languageMap by lazy { languageList.associateBy { it.languageType } }
 
   // contentMap will prevent reading the same content multiple times
@@ -96,7 +96,7 @@ class ReadingBatContent {
   /** Language group for Kotlin challenges. Accessible in the DSL as a property or block receiver. */
   val kotlin by lazy { LanguageGroup<KotlinChallenge>(this, Kotlin) }
 
-  val languages by lazy { listOf(python, java, kotlin) }
+  val languages by lazy { [python, java, kotlin] }
 
   val cacheChallenges get() = isProduction() || isTesting()
 

readingbat-core/src/main/kotlin/com/readingbat/dsl/challenge/Challenge.kt

@@ -95,7 +95,6 @@ sealed class Challenge(
 
   // Allow description updates only if not found in the Content.kt decl
   private val isDescriptionSetInDsl by lazy { description.isNotBlank() }
-  internal val gitpodUrl by lazy { pathOf(repo.sourcePrefix, "blob/$branchName", srcPath, fqName) }
   internal val parsedDescription by lazy { MarkdownParser.toHtml(description) }
   internal val path by lazy { pathOf(languageName, groupName, challengeName) }
 
@@ -308,7 +307,7 @@ class KotlinChallenge(
     val funcCode = "\n${extractKotlinFunction(lines)}\n\n"
     val invocations = extractKotlinInvocations(lines, KotlinParse.funMainRegex, KotlinParse.kotlinEndRegex)
     val script = convertToKotlinScript(lines).also { logger.debug { "Kotlin: $it" } }
-    val correctAnswers = mutableListOf<Any>()
+    val correctAnswers: MutableList<Any> = []
 
     logger.debug { "$challengeName return type: $returnType script: \n${script.withLineNumbers()}" }
 
@@ -360,7 +359,7 @@ class PythonChallenge(
     val funcCode = extractPythonFunction(lines)
     val invocations = extractPythonInvocations(lines, PythonParse.defMainRegex, PythonParse.ifMainEndRegex)
     val script = convertToPythonScript(lines)
-    val correctAnswers = mutableListOf<Any>()
+    val correctAnswers: MutableList<Any> = []
 
     logger.debug { "$challengeName return type: $returnType script: \n${script.withLineNumbers()}" }
 

readingbat-core/src/main/kotlin/com/readingbat/dsl/parse/JavaParse.kt

@@ -48,15 +48,15 @@ internal object JavaParse {
   internal val svmRegex = Regex("""\s*static\s+void\s+main\(""")
 
   private val prefixRegex =
-    listOf(
+    [
       Regex("""System\.out\.println\("""),
       Regex("""ArrayUtils\.arrayPrint\("""),
       Regex("""ListUtils\.listPrint\("""),
       Regex("""arrayPrint\("""),
       Regex("""listPrint\("""),
-    )
+    ]
   private val prefixes =
-    listOf("System.out.println", "ArrayUtils.arrayPrint", "ListUtils.listPrint", "arrayPrint", "listPrint")
+    ["System.out.println", "ArrayUtils.arrayPrint", "ListUtils.listPrint", "arrayPrint", "listPrint"]
 
   /**
    * Derives the return type of a Java challenge function by locating the first `static` method

readingbat-core/src/main/kotlin/com/readingbat/pages/ChallengePage.kt

@@ -706,11 +706,9 @@ internal object ChallengePage {
     val groupName = challenge.groupName
     val challengeName = challenge.challengeName
 
-    p(classes = TwClasses.EXPERIMENT) {
-      +"Experiment with this code on "
-      this@otherLinks.addLink("Gitpod.io", "https://gitpod.io/#${challenge.gitpodUrl}", true)
-      if (languageType.isKotlin) {
-        +" or as a "
+    if (languageType.isKotlin) {
+      p(classes = TwClasses.EXPERIMENT) {
+        +"Experiment with this code as a "
         this@otherLinks.addLink("Kotlin Playground", pathOf(PLAYGROUND_ROOT, groupName, challengeName), false)
       }
     }