LUCENE-10510: Check module access prior to running gjf/spotless tasks (#802)

gradle/generation/local-settings.gradle

@@ -22,6 +22,30 @@
 def hasDefaults = rootProject.file("gradle.properties").exists()
 
 configure(rootProject) {
+  // Add a task verifying that gradle process has access to JVM internals.
+  // this is occasionally needed for certain tasks.
+  task checkJdkInternalsExportedToGradle() {
+    doFirst {
+      def jdkCompilerModule = ModuleLayer.boot().findModule("jdk.compiler").orElseThrow()
+      def gradleModule = getClass().module
+      def internalsExported = [
+          "com.sun.tools.javac.api",
+          "com.sun.tools.javac.file",
+          "com.sun.tools.javac.parser",
+          "com.sun.tools.javac.tree",
+          "com.sun.tools.javac.util"
+      ].stream()
+        .allMatch(pkg -> jdkCompilerModule.isExported(pkg, gradleModule))
+
+      if (!internalsExported) {
+        throw new GradleException(
+            "Certain gradle tasks and plugins require access to jdk.compiler" +
+                " internals, your gradle.properties might have just been generated or could be" +
+                " out of sync (see help/localSettings.txt)")
+      }
+    }
+  }
+
   task localSettings() {
     doFirst {
       // If we don't have the defaults yet, create them.
@@ -43,7 +67,7 @@ systemProp.file.encoding=UTF-8
 # Set up gradle JVM defaults.
 # The heap seems huge but gradle runs out of memory on lower values (don't know why).
 #
-# We also open up internal compiler modules for spotless/ google jaa format.
+# We also open up internal compiler modules for spotless/ google java format.
 org.gradle.jvmargs=-Xmx3g \\
  --add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED \\
  --add-exports jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED \\

gradle/validation/error-prone.gradle

@@ -22,7 +22,7 @@ if (rootProject.usesAltJvm && rootProject.runtimeJavaVersion > JavaVersion.VERSI
 }
 
 if (!Boolean.parseBoolean(propertyOrDefault("tests.nightly", "false"))) {
-  skipReason = "skipped on non-nightly runs, pass -Dtests.nightly=true to run"
+  skipReason = "skipped on non-nightly runs, pass -Ptests.nightly=true to run"
 }
 
 if (skipReason) {
@@ -58,6 +58,8 @@ allprojects { prj ->
       }
 
       tasks.withType(JavaCompile) { task ->
+        task.dependsOn ":checkJdkInternalsExportedToGradle"
+
         options.errorprone.disableWarningsInGeneratedCode = true
         options.errorprone.errorproneArgs = [
             '-Xep:InlineMeSuggester:OFF', // We don't use this annotation

gradle/validation/spotless.gradle

@@ -103,9 +103,11 @@ configure(project(":lucene").subprojects) { prj ->
 
   tasks.matching { task -> task.name == "spotlessApply" }.configureEach { v ->
     tidy.dependsOn v
+    v.dependsOn ":checkJdkInternalsExportedToGradle"
   }
 
   tasks.matching { task -> task.name == "spotlessCheck" }.configureEach { v ->
     check.dependsOn v
+    v.dependsOn ":checkJdkInternalsExportedToGradle"
   }
 }

help/localSettings.txt

@@ -4,9 +4,14 @@ Local developer settings
 The first invocation of any task in Lucene's gradle build will generate
 and save a project-local 'gradle.properties' file. This file contains
 the defaults you may (but don't have to) tweak for your particular hardware
-(or taste).
+(or taste). Note there are certain settings in that file that may
+be _required_ at runtime for certain plugins (an example is the spotless/
+google java format plugin, which requires adding custom exports to JVM modules). Gradle
+build only generates this file if it's not already present (it never overwrites
+the defaults) -- occasionally you may have to manually delete (or move) this
+file and regenerate from scratch.
 
-This is an overview of some of these settings.
+This is an overview of some settings present in gradle.properties.
 
 Parallelism
 -----------