Remove legacy config classes support from extension annotation processor

core/processor/src/main/java/io/quarkus/annotation/processor/ExtensionAnnotationProcessor.java

@@ -15,7 +15,6 @@
 import javax.lang.model.element.Element;
 import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.TypeElement;
-import javax.tools.Diagnostic;
 import javax.tools.Diagnostic.Kind;
 
 import org.jboss.jdeparser.JDeparser;
@@ -54,12 +53,7 @@ public synchronized void init(ProcessingEnvironment processingEnv) {
 
         ExtensionModule extensionModule = utils.extension().getExtensionModule();
 
-        Config config = new Config(extensionModule, useConfigMapping, debug);
-
-        if (!useConfigMapping) {
-            processingEnv.getMessager().printMessage(Diagnostic.Kind.WARNING, "Extension module " + extensionModule.artifactId()
-                    + " config implementation is deprecated. Please migrate to use @ConfigMapping: https://quarkus.io/guides/writing-extensions#configuration");
-        }
+        Config config = new Config(extensionModule, debug);
 
         List<ExtensionProcessor> extensionProcessors = new ArrayList<>();
         extensionProcessors.add(new ExtensionBuildProcessor());

core/processor/src/main/java/io/quarkus/annotation/processor/documentation/config/model/Extension.java

@@ -55,13 +55,6 @@ public boolean equals(Object obj) {
         return Objects.equals(artifactId, other.artifactId) && Objects.equals(groupId, other.groupId);
     }
 
-    // TODO #42114 remove once fixed
-    @Deprecated(forRemoval = true)
-    @JsonIgnore
-    public boolean isMixedModule() {
-        return "io.quarkus".equals(groupId) && ("quarkus-core".equals(artifactId) || "quarkus-vertx-http".equals(artifactId));
-    }
-
     @JsonIgnore
     public Extension normalizeCommonOrInternal() {
         if (!commonOrInternal()) {

core/processor/src/main/java/io/quarkus/annotation/processor/documentation/config/scanner/ConfigAnnotationScanner.java

@@ -66,29 +66,9 @@ public ConfigAnnotationScanner(Config config, Utils utils) {
         List<ConfigAnnotationListener> configRootListeners = new ArrayList<>();
         List<ConfigAnnotationListener> configMappingWithoutConfigRootListeners = new ArrayList<>();
 
-        if (!config.getExtension().isMixedModule()) {
-            // This is what we aim for. We have an exception for Quarkus Core and Quarkus Messaging though.
-            if (config.useConfigMapping()) {
-                configRootListeners.add(new JavadocConfigMappingListener(config, utils, configCollector));
-                configRootListeners.add(new ConfigMappingListener(config, utils, configCollector));
-
-                configMappingWithoutConfigRootListeners.add(new JavadocConfigMappingListener(config, utils, configCollector));
-            } else {
-                configRootListeners.add(new JavadocLegacyConfigRootListener(config, utils, configCollector));
-                configRootListeners.add(new LegacyConfigRootListener(config, utils, configCollector));
-            }
-        } else {
-            // TODO #42114 remove once fixed
-            // we handle both traditional config roots and config mappings
-            if (config.getExtension().isMixedModule()) {
-                configRootListeners.add(new JavadocConfigMappingListener(config, utils, configCollector));
-                configRootListeners.add(new JavadocLegacyConfigRootListener(config, utils, configCollector));
-                configRootListeners.add(new ConfigMappingListener(config, utils, configCollector));
-                configRootListeners.add(new LegacyConfigRootListener(config, utils, configCollector));
-
-                configMappingWithoutConfigRootListeners.add(new JavadocConfigMappingListener(config, utils, configCollector));
-            }
-        }
+        configRootListeners.add(new JavadocConfigMappingListener(config, utils, configCollector));
+        configRootListeners.add(new ConfigMappingListener(config, utils, configCollector));
+        configMappingWithoutConfigRootListeners.add(new JavadocConfigMappingListener(config, utils, configCollector));
 
         this.configRootListeners = Collections.unmodifiableList(configRootListeners);
         this.configMappingWithoutConfigRootListeners = Collections.unmodifiableList(configMappingWithoutConfigRootListeners);
@@ -481,28 +461,10 @@ private <T extends DiscoveryRootElement> T applyRootListeners(
     }
 
     private void checkConfigRootAnnotationConsistency(TypeElement configRoot) {
-        // for now quarkus-core is a mix of both @ConfigRoot and @ConfigMapping
-        // see https://github.com/quarkusio/quarkus/issues/42114
-        // same for Quarkus Messaging
-        // TODO #42114 remove once fixed
-        if (config.getExtension().isMixedModule()) {
-            return;
-        }
-
-        if (config.useConfigMapping()) {
-            if (!utils.element().isAnnotationPresent(configRoot, Types.ANNOTATION_CONFIG_MAPPING)) {
-                throw new IllegalStateException(
-                        "This module is configured to use @ConfigMapping annotations but we found a @ConfigRoot without a corresponding @ConfigMapping annotation in: "
-                                + configRoot + "."
-                                + " Either add the annotation or add the -AlegacyConfigRoot=true argument to the annotation processor config in the pom.xml");
-            }
-        } else {
-            if (utils.element().isAnnotationPresent(configRoot, Types.ANNOTATION_CONFIG_MAPPING)) {
-                throw new IllegalStateException(
-                        "This module is configured to use legacy @ConfigRoot annotations but we found a @ConfigMapping annotation in: "
-                                + configRoot + "."
-                                + " Check the configuration of the annotation processor and drop the -AlegacyConfigRoot=true argument from the pom.xml if needed");
-            }
+        if (!utils.element().isAnnotationPresent(configRoot, Types.ANNOTATION_CONFIG_MAPPING)) {
+            throw new IllegalStateException(
+                    "We found a @ConfigRoot without a corresponding @ConfigMapping annotation in: " + configRoot + "."
+                            + " Make sure your configuration interfaces are annotated with @ConfigMapping.");
         }
     }