Fix multi-jdk testing setup (#1086)

This changes the Gradle build to always create multi-jdk tasks,
and instead use the `enabled` property to determine whether the task
is actually ran or not.

The has the following benefits:
* IntelliJ and other tools understand the task execution graph (e.g. testJdk20 shows up as a task)
* JDK-specific Gradle configurations always exist, so `updateDependencyLocks` is consistent.

buildSrc/src/main/kotlin/BuildInfo.kt

@@ -210,10 +210,18 @@ open class BuildInfo(private val project: Project) {
   // Assembles a collection of JDK versions which tests can be run against, considering ancillary
   // parameters like `testAllJdks` and `testExperimentalJdks`.
   val jdkTestRange: Collection<JavaLanguageVersion> by lazy {
-    JavaVersionRange.inclusive(jdkTestFloor, jdkTestCeiling).filter { version ->
-      // unless we are instructed to test all JDKs, tests only include LTS releases and
-      // versions above the toolchain version.
-      testAllJdks || (JavaVersionRange.isLTS(version) || version >= jdkToolchainVersion)
+    JavaVersionRange.inclusive(jdkTestFloor, jdkTestCeiling).toList()
+  }
+
+  val JavaLanguageVersion.isEnabled: Boolean
+    get() = isVersionEnabled(this)
+
+  fun isVersionEnabled(version: JavaLanguageVersion): Boolean {
+    return when {
+      testAllJdks -> true
+      multiJdkTesting -> JavaVersionRange.isLTS(version)
+      testExperimentalJdks -> version > jdkToolchainVersion
+      else -> false
     }
   }
 
@@ -287,13 +295,6 @@ open class BuildInfo(private val project: Project) {
             // multiply out by jdk vendor
             testJdkVendors.map { vendor -> (targetVersion to vendor) }
           }
-          .filter { (jdkTarget, vendor) ->
-            // only include experimental tasks in the return suite if the flag is set. if the task
-            // is withheld from the returned list, it will not be executed by default with `gradle
-            // check`.
-            testExperimentalJdks ||
-              (!namer(jdkTarget, vendor.takeIf { isMultiVendor }).contains("Experimental"))
-          }
           .map { (jdkTarget, vendor) ->
             if (jdkToolchainVersion == jdkTarget)
               tasks.register(namer(jdkTarget, vendor)) {
@@ -310,10 +311,10 @@ open class BuildInfo(private val project: Project) {
               ) {
                 targets.all {
                   testTask.configure {
+                    enabled = jdkTarget.isEnabled
                     group = Category.VERIFICATION
                     description = "Run tests against JDK ${jdkTarget.asInt()}"
                     applyConfig(jdkTarget to toolchains.launcherFor { languageVersion = jdkTarget })
-
                     // fix: on jdk17, we must force the polyglot module on to the modulepath
                     if (jdkTarget.asInt() == 17)
                       jvmArgumentProviders.add(
@@ -342,9 +343,8 @@ open class BuildInfo(private val project: Project) {
   }
 
   val multiJdkTesting: Boolean by lazy {
-    // By default, Pkl is tested against a full range of JDK versions, past and present, within the
-    // supported bounds of `PKL_TEST_JDK_TARGET` and `PKL_TEST_JDK_MAXIMUM`. To opt-out of this
-    // behavior, set `-DpklMultiJdkTesting=false` on the Gradle command line.
+    // Test Pkl against a full range of JDK versions, past and present, within the
+    // supported bounds of `PKL_TEST_JDK_TARGET` and `PKL_TEST_JDK_MAXIMUM`.
     //
     // In CI, this defaults to `true` to catch potential cross-JDK compat regressions or other bugs.
     // In local dev, this defaults to `false` to speed up the build and reduce contributor load.

buildSrc/src/main/kotlin/pklJavaExecutable.gradle.kts

@@ -84,6 +84,7 @@ val testStartJavaExecutable by tasks.registering { setupTestStartJavaExecutable(
 val testStartJavaExecutableOnOtherJdks =
   buildInfo.jdkTestRange.map { jdkTarget ->
     tasks.register("testStartJavaExecutableJdk${jdkTarget.asInt()}") {
+      enabled = buildInfo.isVersionEnabled(jdkTarget)
       val toolChainService: JavaToolchainService = serviceOf()
       val launcher = toolChainService.launcherFor { languageVersion = jdkTarget }
       setupTestStartJavaExecutable(launcher)
@@ -94,9 +95,7 @@ tasks.assemble { dependsOn(javaExecutable) }
 
 tasks.check {
   dependsOn(testStartJavaExecutable)
-  if (buildInfo.multiJdkTesting) {
-    dependsOn(testStartJavaExecutableOnOtherJdks)
-  }
+  dependsOn(testStartJavaExecutableOnOtherJdks)
 }
 
 publishing {

buildSrc/src/main/kotlin/pklJavaLibrary.gradle.kts

@@ -20,6 +20,7 @@ import org.gradle.accessors.dm.LibrariesForLibs
 plugins {
   `java-library`
   `jvm-toolchains`
+  `jvm-test-suite`
   id("pklKotlinTest")
   id("com.diffplug.spotless")
 }
@@ -135,4 +136,4 @@ tasks.test { configureJdkTestTask(info.javaTestLauncher) }
 // inherits the configuration of the default `test` task (aside from an overridden launcher).
 val jdkTestTasks = info.multiJdkTestingWith(tasks.test) { (_, jdk) -> configureJdkTestTask(jdk) }
 
-if (info.multiJdkTesting) tasks.check { dependsOn(jdkTestTasks) }
+tasks.check { dependsOn(jdkTestTasks) }