jqno#231: improves error messages regarding @EmbeddedId

CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 
 ## [Unreleased]
+### Fixed
+- Improved error messages regarding JPA's `@EmbeddedId` annotation. ([Issue 231](https://github.com/jqno/equalsverifier/issues/231))
 
 
 <a name="3.x"/>

src/main/java/nl/jqno/equalsverifier/Warning.java

@@ -163,13 +163,14 @@ public enum Warning {
     STRICT_INHERITANCE,
 
     /**
-     * Disables the check that fields marked with the @Id annotation in JPA
-     * entities may not be used in the {@code equals} contract.
-     * <p>
-     * When this warning is suppressed, the fields marked with @Id will become
-     * the entity's surrogate key. Only these fields can now be part of the
-     * {@code equals} contract; all other fields may no longer be used in
-     * {@code equals}.
+     * Disables the check that fields marked with the @Id or @EmbeddedId
+     * annotations in JPA entities may not be used in the {@code equals}
+     * contract.
+     * <p>
+     * When this warning is suppressed, the fields marked with @Id
+     * or @EmbeddedId will become the entity's surrogate key. Only these fields
+     * can now be part of the {@code equals} contract; all other fields may no
+     * longer be used in {@code equals}.
      */
     SURROGATE_KEY,
 

src/main/java/nl/jqno/equalsverifier/internal/checkers/fieldchecks/SignificantFieldCheck.java

@@ -122,7 +122,7 @@ private void assertFieldShouldHaveBeenUsed(String fieldName, boolean equalsChang
         }
         else if (anotherFieldIsMarkedAsId) {
             message = "Significant fields: equals does not use %%, or it is stateless.\n" +
-                "Suppress Warning.SURROGATE_KEY if you want to use only the @Id field(s).";
+                "Suppress Warning.SURROGATE_KEY if you want to use only the @Id or @EmbeddedId field(s).";
         }
         else {
             message = "Significant fields: equals does not use %%, or it is stateless.";
@@ -137,11 +137,11 @@ private void assertFieldShouldNotBeUsed(String fieldName, boolean equalsChanged,
         final String message;
         if (thisFieldIsMarkedAsId) {
             message = "Significant fields: %% is marked @Id or @EmbeddedId so equals should not use it, but it does.\n" +
-                "Suppress Warning.SURROGATE_KEY if you want to use only the @Id field(s).";
+                "Suppress Warning.SURROGATE_KEY if you want to use only the @Id or @EmbeddedId field(s).";
         }
         else if (anotherFieldIsMarkedAsId) {
             message = "Significant fields: equals should not use %% because Warning.SURROGATE_KEY is suppressed" +
-                " and it is not marked as @Id, but it does.";
+                " and it is not marked as @Id or @EmbeddedId, but it does.";
         }
         else {
             message = "Significant fields: equals should not use %%, but it does.";

src/main/java/nl/jqno/equalsverifier/internal/reflection/annotations/SupportedAnnotations.java

@@ -138,9 +138,9 @@ public boolean validate(AnnotationProperties properties, AnnotationCache annotat
     TRANSIENT(true, "javax.persistence.Transient"),
 
     /**
-     * Fields in JPA Entities that are marked @Id are usually part of the
-     * entity's surrogate key. EqualsVerifier will therefore assume that it
-     * must not be used in the equals/hashCode contract, unless
+     * Fields in JPA Entities that are marked @Id or @EmbeddedId are usually
+     * part of the entity's surrogate key. EqualsVerifier will therefore assume
+     * that it must not be used in the equals/hashCode contract, unless
      * {@link Warning#SURROGATE_KEY} is suppressed.
      */
     ID(false, "javax.persistence.Id", "javax.persistence.EmbeddedId") {

src/main/java/nl/jqno/equalsverifier/internal/util/Validations.java

@@ -102,8 +102,8 @@ private static void validateClassAnnotations(
     private static void validateFieldAnnotations(Class<?> type, AnnotationCache cache, Set<String> includedFields) {
         FieldIterable.of(type).forEach(f ->
             validate(includedFields.contains(f.getName()) && cache.hasFieldAnnotation(type, f.getName(), SupportedAnnotations.ID),
-                "you can't use withOnlyTheseFields on a field marked @Id.\n" +
-                "Suppress Warning.SURROGATE_KEY if you want to use only the @Id fields in equals.")
+                "you can't use withOnlyTheseFields on a field marked @Id or @EmbeddedId.\n" +
+                "Suppress Warning.SURROGATE_KEY if you want to use only the @Id or @EmbeddedId fields in equals.")
         );
     }
 

src/test/java/nl/jqno/equalsverifier/integration/extra_features/JpaIdTest.java

@@ -97,6 +97,14 @@ public void fail_whenIdFieldIsNotUsed_givenIdIsAnnotatedWithEmbeddedIdAndSurroga
                 .verify();
     }
 
+    @Test
+    public void fail_whenEmbeddedIdFieldIsTheOnlyFieldUsed() {
+        expectFailure("Precondition: you can't use withOnlyTheseFields on a field marked @Id or @EmbeddedId.", "Suppress Warning.SURROGATE_KEY if");
+        EqualsVerifier.forClass(JpaEmbeddedIdBusinessKeyPerson.class)
+            .withOnlyTheseFields("id")
+            .verify();
+    }
+
     @Test
     public void succeed_whenOnlySocialSecurityIsUsed_givenSocialSecurityIsAnnotatedWithNaturalId() {
         EqualsVerifier.forClass(NaturalIdBusinessKeyPerson.class)
@@ -158,7 +166,7 @@ public void succeed_whenMethodsAreAnnotatedInsteadOfFields() {
 
     @Test
     public void fail_whenIdFieldIsTheOnlyFieldUsed() {
-        expectFailure("Precondition: you can't use withOnlyTheseFields on a field marked @Id.", "Suppress Warning.SURROGATE_KEY if");
+        expectFailure("Precondition: you can't use withOnlyTheseFields on a field marked @Id or @EmbeddedId.", "Suppress Warning.SURROGATE_KEY if");
         EqualsVerifier.forClass(JpaIdBusinessKeyPerson.class)
                 .withOnlyTheseFields("id")
                 .verify();