Adding Config Registry Linter to Ensure Alias Keys Are Documented

.gitlab-ci.yml

@@ -374,7 +374,7 @@ config-inversion-linter:
   needs: []
   script:
     - ./gradlew --version
-    - ./gradlew logEnvVarUsages checkEnvironmentVariablesUsage checkConfigStrings
+    - ./gradlew logEnvVarUsages checkEnvironmentVariablesUsage checkConfigStrings verifyAliasKeysAreSupported
 
 test_published_artifacts:
   extends: .gradle_build

buildSrc/src/main/kotlin/datadog/gradle/plugin/config/ConfigInversionLinter.kt

@@ -23,6 +23,46 @@ class ConfigInversionLinter : Plugin<Project> {
     registerLogEnvVarUsages(target, extension)
     registerCheckEnvironmentVariablesUsage(target)
     registerCheckConfigStringsTask(target, extension)
+    verifyAliasKeysAreSupported(target, extension)
+  }
+}
+
+// Data class for fields from generated class
+private data class LoadedConfigFields(
+  val supported: Set<String>,
+  val aliases: Map<String, List<String>> = emptyMap(),
+  val aliasMapping: Map<String, String> = emptyMap()
+)
+
+// Cache for fields from generated class
+private var cachedConfigFields: LoadedConfigFields? = null
+
+// Helper function to load fields from the generated class
+private fun loadConfigFields(
+  mainSourceSetOutput: org.gradle.api.file.FileCollection,
+  generatedClassName: String
+): LoadedConfigFields {
+  return cachedConfigFields ?: run {
+    val urls = mainSourceSetOutput.files.map { it.toURI().toURL() }.toTypedArray()
+    URLClassLoader(urls, LoadedConfigFields::class.java.classLoader).use { cl ->
+      val clazz = Class.forName(generatedClassName, true, cl)
+
+      val supportedField = clazz.getField("SUPPORTED").get(null)
+      @Suppress("UNCHECKED_CAST")
+      val supportedSet = when (supportedField) {
+        is Set<*> -> supportedField as Set<String>
+        is Map<*, *> -> supportedField.keys as Set<String>
+        else -> throw IllegalStateException("SUPPORTED field must be either Set<String> or Map<String, Any>, but was ${supportedField?.javaClass}")
+      }
+
+      @Suppress("UNCHECKED_CAST")
+      val aliases = clazz.getField("ALIASES").get(null) as Map<String, List<String>>
+
+      @Suppress("UNCHECKED_CAST")
+      val aliasMappingMap = clazz.getField("ALIAS_MAPPING").get(null) as Map<String, String>
+
+      LoadedConfigFields(supportedSet, aliases, aliasMappingMap)
+    }.also { cachedConfigFields = it }
   }
 }
 
@@ -246,3 +286,44 @@ private fun registerCheckConfigStringsTask(project: Project, extension: Supporte
     }
   }
 }
+
+
+/** Registers `verifyAliasKeysAreSupported` to ensure all alias keys are documented as supported configurations. */
+private fun verifyAliasKeysAreSupported(project: Project, extension: SupportedTracerConfigurations) {
+  val ownerPath = extension.configOwnerPath
+  val generatedFile = extension.className
+
+  project.tasks.register("verifyAliasKeysAreSupported") {
+    group = "verification"
+    description =
+      "Verifies that all alias keys in `metadata/supported-configurations.json` are also documented as supported configurations."
+
+    val mainSourceSetOutput = ownerPath.map {
+      project.project(it)
+        .extensions.getByType<SourceSetContainer>()
+        .named(SourceSet.MAIN_SOURCE_SET_NAME)
+        .map { main -> main.output }
+    }
+    inputs.files(mainSourceSetOutput)
+
+    doLast {
+      val configFields = loadConfigFields(mainSourceSetOutput.get().get(), generatedFile.get())
+      val supported = configFields.supported
+      val aliases = configFields.aliases.keys
+
+      val unsupportedAliasKeys = aliases - supported
+      val violations = buildList {
+        unsupportedAliasKeys.forEach { key ->
+          add("$key is listed as an alias key but is not documented as a supported configuration in the `supportedConfigurations` key")
+        }
+      }
+      if (violations.isNotEmpty()) {
+        logger.error("\nFound alias keys not documented as supported configurations:")
+        violations.forEach { logger.lifecycle(it) }
+        throw GradleException("Undocumented alias keys found. Please add the above keys to the `supportedConfigurations` in '${extension.jsonFile.get()}'.")
+      } else {
+        logger.info("All alias keys are documented as supported configurations.")
+      }
+    }
+  }
+}