Minify the shadowed JAR with R8

core/build.gradle.kts

@@ -50,7 +50,7 @@ val generateSources =
 
 tasks {
   // Run tests with UTF-16 encoding
-  test {
+  withType<Test> {
     useJUnitPlatform()
     jvmArgs("-Dfile.encoding=UTF-16")
   }
@@ -90,6 +90,27 @@ tasks {
     archiveClassifier = "with-dependencies"
     duplicatesStrategy = DuplicatesStrategy.EXCLUDE
     failOnDuplicateEntries = true
+    minimize {
+      r8 {
+        keepRuleFiles.from(layout.projectDirectory.file("src/main/rules.txt"))
+      }
+    }
+  }
+
+  val testShadow =
+      register("testShadow", Test::class) {
+        group = "verification"
+        description =
+            "Runs unit tests against the R8-processed shadowed JAR to ensure Maven API compatibility."
+        // Replace normal Jar with shadowJar in tests.
+        classpath =
+            (sourceSets["test"].runtimeClasspath - sourceSets["main"].output) +
+                files(shadowJar.flatMap { it.archiveFile })
+        testClassesDirs = sourceSets["test"].output.classesDirs
+      }
+
+  check {
+    dependsOn(testShadow)
   }
 }
 

core/src/main/rules.txt

@@ -0,0 +1,28 @@
+-dontobfuscate
+-keepattributes SourceFile, LineNumberTable
+
+
+-dontwarn com.google.auto.**
+-dontwarn gnu.trove.**
+-dontwarn kotlin.annotations.jvm.**
+-dontwarn kotlinx.coroutines.internal.intellij.**
+-dontwarn org.checkerframework.checker.nullness.qual.Nullable
+-dontwarn org.jetbrains.annotations.**
+-dontwarn org.jetbrains.kotlin.com.google.errorprone.annotations.**
+-dontwarn org.jetbrains.kotlin.com.google.j2objc.annotations.**
+-dontwarn org.jetbrains.kotlin.com.intellij.util.**
+
+
+# Keep all ktfmt library classes and methods for Maven API, CLI, and unit test compatibility.
+-keep class org.jetbrains.ktfmt.** { *; }
+
+# IntelliJ platform classes required for Kotlin AST parsing & CoreApplicationEnvironment.
+-keep class org.jetbrains.kotlin.com.intellij.**
+
+# Kotlin AST PSI and KDoc elements (keep constructors for reflective ASTFactory instantiation).
+-keepclassmembers class org.jetbrains.kotlin.psi.** {
+    public <init>(...);
+}
+-keepclassmembers class org.jetbrains.kotlin.kdoc.** {
+    public <init>(...);
+}

gradle/libs.versions.toml

@@ -10,7 +10,7 @@ org-junit-junit-bom = "6.1.2"
 gradlePlugin-dependencyAnalysis = "3.18.0"
 gradlePlugin-dokka = "2.2.0"
 gradlePlugin-intelliJPlatform = "2.12.0"
-gradlePlugin-shadowJar = "9.0.2"
+gradlePlugin-shadowJar = "9.6.1"
 
 [libraries]
 ec4j = { module = "org.ec4j.core:ec4j-core", version.ref = "org-ec4j-core" }

settings.gradle.kts

@@ -38,6 +38,7 @@ dependencyResolutionManagement {
   }
   repositories {
     mavenCentral()
+    google()
   }
 }