Add a consistency check task for defined versions

Author: jjohannes

gradle/plugins/src/main/kotlin/org.example.gradle.feature.use-all-catalog-versions.gradle.kts

@@ -1,4 +1,9 @@
-plugins { id("org.gradle.java-platform") }
+import org.example.gradle.tasks.JavaVersionConsistencyCheck
+
+plugins {
+    id("org.gradle.java-platform")
+    id("org.example.gradle.base.lifecycle")
+}
 
 // Allow upgrading (transitive) versions via catalog by adding constraints
 dependencies.constraints {
@@ -11,3 +16,15 @@ dependencies.constraints {
         }
     }
 }
+
+tasks.register<JavaVersionConsistencyCheck>("checkVersionConsistency") {
+    definedVersions = provider {
+        configurations["api"].dependencyConstraints.associate { "${it.group}:${it.name}" to it.version!! }
+    }
+    aggregatedClasspath = provider { configurations["mainRuntimeClasspath"].incoming.resolutionResult.allComponents }
+    reportFile = layout.buildDirectory.file("reports/version-consistency.txt")
+}
+
+tasks.named("qualityCheck") { dependsOn(tasks.named("checkVersionConsistency")) }
+
+tasks.named("qualityGate") { dependsOn(tasks.named("checkVersionConsistency")) }

gradle/plugins/src/main/kotlin/org/example/gradle/tasks/JavaVersionConsistencyCheck.kt

@@ -0,0 +1,50 @@
+package org.example.gradle.tasks
+
+import org.gradle.api.DefaultTask
+import org.gradle.api.artifacts.component.ModuleComponentIdentifier
+import org.gradle.api.artifacts.result.ResolvedComponentResult
+import org.gradle.api.file.RegularFileProperty
+import org.gradle.api.provider.MapProperty
+import org.gradle.api.provider.SetProperty
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.TaskAction
+
+abstract class JavaVersionConsistencyCheck : DefaultTask() {
+
+    @get:Input abstract val definedVersions: MapProperty<String, String>
+
+    @get:Input abstract val aggregatedClasspath: SetProperty<ResolvedComponentResult>
+
+    @get:OutputFile abstract val reportFile: RegularFileProperty
+
+    @TaskAction
+    fun compare() {
+        var potentiallyUnusedVersion = ""
+        var wrongVersions = ""
+        definedVersions.get().forEach { (id, version) ->
+            val resolved =
+                aggregatedClasspath.get().find {
+                    val resolvedId = it.id
+                    resolvedId is ModuleComponentIdentifier && resolvedId.moduleIdentifier.toString() == id
+                }
+            if (resolved == null) {
+                potentiallyUnusedVersion += "Not used in production code: $id:$version\n"
+            } else {
+                val resolvedVersion = resolved.moduleVersion?.version
+                if (resolvedVersion != version) {
+                    wrongVersions += "Wrong version: $id (declared=$version; used=$resolvedVersion)\n"
+                }
+            }
+        }
+
+        reportFile.get().asFile.writeText(potentiallyUnusedVersion + wrongVersions)
+
+        if (!potentiallyUnusedVersion.isEmpty()) {
+            println(potentiallyUnusedVersion)
+        }
+        if (!wrongVersions.isEmpty()) {
+            throw RuntimeException(wrongVersions)
+        }
+    }
+}

gradle/versions/build.gradle.kts

@@ -1,6 +1,5 @@
 plugins {
     id("org.example.gradle.base.dependency-rules")
-    id("org.example.gradle.base.lifecycle")
     id("org.example.gradle.feature.use-all-catalog-versions")
     id("org.example.gradle.check.format-gradle")
 }