Dump grade submodule dependency graph as Graphiz

depgraph.kts

fun dependencyGraph(project: Project): Map<String, List<String>> {
    fun Dependency.qualifiedName() = toString().substringAfter("'").substringBefore("'")

    return project.configurations.flatMap { cfg ->
        cfg.dependencies
            .filter { project.path != it.qualifiedName() }
            .filter { dep ->
                dep.toString().startsWith("project") ||
                        dep.toString().startsWith("DefaultProjectDependency")

            }
    }.distinctBy { it.qualifiedName() }
        .map { dep ->
            project.path to dep.qualifiedName()
        }
        .groupToLists()

}

fun <A, B> List<Pair<A, B>>.groupToLists(): Map<A, List<B>> {
    return groupingBy { it.first }
        .aggregate { _, accumulator, element, _ ->
            (accumulator ?: emptyList()) + (element.second)
        }
}

fun projectDependencyGraph(project: Project): Map<String, List<String>> = buildMap {
    putAll(dependencyGraph(project))
    project.subprojects.forEach { subproject ->
        putAll(projectDependencyGraph(subproject))
    }
}

rootProject.tasks.register("deps") {
    group = "verification"
    println(rootProject.group)
    println("digraph {")
    val graph = projectDependencyGraph(rootProject).toSortedMap()
    println("""  node [shape=box, style="rounded,filled", fillcolor="#e8e8e8", fontname="Helvetica"]""")
    println("""  edge [color="#666666"]""")
    graph.keys.distinct().sorted().map { path ->
        path.split(':').getOrNull(1) to path
    }.filter { it.first != null }.groupToLists().forEach { (group, projects) ->
        println("""  subgraph cluster_${group?.replace('-', '_')} {""")
        println("""    label = "$group";""")
        println("""    style="rounded,dashed"""")
        println("""    fontname="Helvetica-Bold""")
        projects.forEach { project ->
            println("""    "$project";""")
        }
        println("  }")
    }
    graph.entries.forEach { (project, deps) ->
        deps.sorted().forEach { dep ->
            println("  \"$project\" -> \"$dep\"")
        }
    }
    println("}")
}