Need help about configuring Gradle for build/javadoc for publishing, with subprojects

Question

EDIT: Things have been dramatically changed. Here are the latest question.

---

I want to configure my Gradle project with multiple subproject to use shadowed jar as main jar, and to create javadoc with it.

Here are my current goals:

1. When I run gradle publishToMavenLocal or gradle publish, Gradle must generate these files:
   1. Shadow Jar as Main:
      Since only reason I use shadow plugin in root project is combining all subprojects as one, the shadow jar must be main jar, which doesn't have any postfix like -all, -dev-all etc.
   2. Create javadoc of all subprojects:
      Each subprojects have javadoc comment on their source code. I want to create combined javadoc-like thing when publishing.

So, after publishing, there should be mol-1.0.0-SNAPSHOT.jar(shadow jar) and mol-1.0.0-SNAPSHOT-javadoc.jar(javadoc) present in Maven repository. (mol is name of my project)

---

Here are my Gradle build scripts. You can inspect full codes in GitHub repo because there are too many files related to.

NOTE: I think I've over-engineered my build script. So I minified my build scripts so no buildSrc is needed.

// <root>/build.gradle.kts
import org.gradle.api.attributes.Bundling.BUNDLING_ATTRIBUTE
import org.gradle.api.attributes.Bundling.EXTERNAL
import org.gradle.api.attributes.Category.CATEGORY_ATTRIBUTE
import org.gradle.api.attributes.Category.VERIFICATION
import org.gradle.api.attributes.VerificationType.MAIN_SOURCES
import org.gradle.api.attributes.VerificationType.VERIFICATION_TYPE_ATTRIBUTE
import org.gradle.kotlin.dsl.named

plugins {
  `java-library`
  `maven-publish`
  id("com.github.johnrengelman.shadow") version("7.1.2")
  //id("io.freefair.aggregate-javadoc") version("6.5.1")
  id("io.freefair.aggregate-javadoc-jar") version("6.5.1")
}

@Suppress("UnstableApiUsage")
val mainSources by configurations.creating<Configuration> {
  isVisible = false
  isCanBeResolved = true
  isCanBeConsumed = false

  attributes {
    attribute(CATEGORY_ATTRIBUTE, objects.named(VERIFICATION))
    attribute(BUNDLING_ATTRIBUTE, objects.named(EXTERNAL))
    attribute(VERIFICATION_TYPE_ATTRIBUTE, objects.named(MAIN_SOURCES))
  }
}

dependencies {
  implementation(project(":bukkit_1_19_R1", "reobf")) {
    isTransitive = false
  }
  implementation(project(":core"))

  mainSources(project(":bukkit_1_19_R1"))
  mainSources(project(":core"))
}

tasks {
  java {
    toolchain.languageVersion.set(JavaLanguageVersion.of(17))
  }
  build {
    dependsOn(shadowJar)
  }
  shadowJar {
    archiveClassifier.set("")
  }
}

allprojects {
  group = "com.github.exmsrv"
  version = "1.0.0-SNAPSHOT"
}

@file:Suppress("UnstableApiUsage")

dependencyResolutionManagement {
  repositories {
    mavenCentral()
    maven("https://repo.papermc.io/repository/maven-public/")
  }

  pluginManagement {
    repositories {
      gradlePluginPortal()
      mavenCentral()
      maven("https://repo.papermc.io/repository/maven-public/")
    }
  }
}

rootProject.name = "mol"

include("core")
include("bukkit_1_19_R1")

// <root>/bukkit_1_19_R1/build.gradle.kts
plugins {
  `java-library`
  id("io.papermc.paperweight.userdev") version("1.3.8")
}

dependencies {
  compileOnly(project(":core"))
  paperweightDevelopmentBundle("io.papermc.paper:dev-bundle:1.19.2-R0.1-SNAPSHOT")
}

// <root>/core/build.gradle.kts
plugins {
  `java-library`
}

dependencies {
  compileOnly("io.papermc.paper:paper-api:1.19.2-R0.1-SNAPSHOT")
}
// Do not put publishing block because it will be shadowed by shadowJar

As you can see, these are not 'complete'. I need help for completing these scripts.

---

NOTE: I've managed to publish shadowed jar as main, but for some reason, aggregateJavadocJar task takes too long to process. After inspecting javadoc.options file, it turned out it tried to create uber-javadoc which contains javadocs of every dependencies.

This is not what I meant. I want javadoc link to other javadoc link if it is not my code.

Here is what I found (javadoc.options)