fix: provide more context when group/plural are missing

Fixes #4396

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 #### Improvements
 * Fix #4348: Introduce specific annotations for the generators
+* Fix #4396: Provide more error context when @Group/@Version annotations are missing
 
 #### Dependency Upgrade
 * Fix #4383: bump snakeyaml from 1.30 to 1.31

kubernetes-model-generator/kubernetes-model-common/src/main/java/io/fabric8/kubernetes/model/annotation/Group.java

@@ -30,6 +30,6 @@
 @Target({TYPE})
 @Retention(RUNTIME)
 public @interface Group {
-
+  String NAME = Group.class.getSimpleName();
   String value();
 }

kubernetes-model-generator/kubernetes-model-common/src/main/java/io/fabric8/kubernetes/model/annotation/Version.java

@@ -29,6 +29,7 @@
 @Target({TYPE})
 @Retention(RetentionPolicy.RUNTIME)
 public @interface Version {
+  String NAME = Version.class.getSimpleName();
 
   /**
    * The name of this version.

kubernetes-model-generator/kubernetes-model-core/src/main/java/io/fabric8/kubernetes/api/model/HasMetadata.java

@@ -84,8 +84,7 @@ static String getApiVersion(Class<?> clazz) {
     }
     if (group != null || version != null) {
       throw new IllegalArgumentException(
-        "You need to specify both @" + Group.class.getSimpleName() + " and @"
-          + Version.class.getSimpleName() + " annotations if you specify either");
+        "You need to specify both @" + Group.NAME + " and @" + Version.NAME + " annotations if you specify either");
     }
     return null;
   }
@@ -158,7 +157,13 @@ default String getSingular() {
   }
 
   static String getFullResourceName(Class<?> clazz) {
-    return getFullResourceName(getPlural(clazz), getGroup(clazz));
+    final String plural = getPlural(clazz);
+    final String group = getGroup(clazz);
+    if (plural == null || group == null) {
+      throw new IllegalArgumentException(
+        "Should provide non-null plural and/or group. Is " + clazz.getName() + " properly annotated with @" + Group.NAME + " and/or @" + Version.NAME + "?");
+    }
+    return getFullResourceName(plural, group);
   }
 
   static String getFullResourceName(String plural, String group) {
@@ -168,6 +173,7 @@ static String getFullResourceName(String plural, String group) {
   }
 
   @JsonIgnore
+  @SuppressWarnings("unused")
   default String getFullResourceName() {
     return getFullResourceName(getClass());
   }