Dokka 2.0.0 Multimodule Configuration Requires Manual Dependencies, Breaking Gradle Build Conventions

[leinardi]

Describe the bug
After migrating from Dokka Gradle Plugin (DGP) version 1.x to 2.0.0 in a multimodule project, it is no longer possible to rely on Gradle's build conventions for specifying which modules should generate documentation. Previously, modules could be configured automatically by applying the plugin and using a simple dokkaHtmlMultiModule block in the root build.gradle.kts. In version 2.0.0, manual configuration of dokka dependencies in the root build.gradle.kts is required, making it challenging to manage projects with dynamically loaded modules.

Expected behaviour
It should be possible to easily specify which modules generate documentation, ideally by marking them directly in their respective build.gradle.kts files, without the need for manual dependency declarations in the root build.gradle.kts. This would allow automation and better integration with Gradle build conventions.

Screenshots
N/A

To Reproduce
Steps to reproduce the behavior:

1. Set up a multimodule project with Dokka 2.0.0 and Gradle v8.12.
2. Attempt to configure the project to generate documentation for select modules using only the root build.gradle.kts and Gradle build conventions without manually specifying the dokka dependencies in the root build.gradle.kts.

Installation

• Operating system: Ubuntu 24.04
• Build tool: Gradle v8.12
• Dokka version: 2.0.0

Additional context
The inability to rely on Gradle build conventions for specifying modules adds complexity to managing multimodule projects with dynamic and static modules. Having to maintain a separate source of truth for Dokka dependencies in the root build.gradle.kts hinders automation and introduces redundancy. A feature or mechanism to mark a project as a Dokka dependency directly in its build.gradle.kts file would greatly enhance usability.

[adam-enko]

Discussed in Kotlin Slack thread (archive)

[Laxystem]

For my project, Spock, I fixed this by creating a docs subproject, and calling :docs:dokkaGenerate instead.