Improve error message if store module doesn't support a well-known fragment interface.

We now throw a RepositoryCreationException (or subclass) when a repository cannot be created due to a missing fragment, a fragment without implementation or if a well-known fragment is not supported by the repository factory.

Throw QueryCreationException if QueryExecutorMethodInterceptor cannot resolve a RepositoryQuery.

Closes #2341
Original pull request: #2342.

src/test/java/org/springframework/data/repository/core/support/RepositoryCompositionUnitTests.java

@@ -136,16 +136,17 @@ class RepositoryCompositionUnitTests {
 		assertThat(barFoo.invoke(barFoo.findMethod(getString).get())).isEqualTo("bar");
 	}
 
-	@Test // DATACMNS-102
+	@Test // DATACMNS-102, GH-2341
 	void shouldValidateStructuralFragments() {
 
 		RepositoryComposition mixed = RepositoryComposition.of(RepositoryFragment.structural(QueryByExampleExecutor.class),
 				RepositoryFragment.implemented(backingRepo));
 
-		assertThatIllegalStateException() //
+		assertThatExceptionOfType(FragmentNotImplementedException.class) //
 				.isThrownBy(mixed::validateImplementation) //
 				.withMessageContaining(
-						"Fragment org.springframework.data.repository.query.QueryByExampleExecutor has no implementation.");
+						"Fragment org.springframework.data.repository.query.QueryByExampleExecutor")
+				.withMessageContaining("has no implementation");
 	}
 
 	@Test // DATACMNS-102

src/test/java/org/springframework/data/repository/core/support/RepositoryFactorySupportUnitTests.java

@@ -51,6 +51,7 @@ import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.projection.ProjectionFactory;
+import org.springframework.data.querydsl.QuerydslPredicateExecutor;
 import org.springframework.data.repository.PagingAndSortingRepository;
 import org.springframework.data.repository.Repository;
 import org.springframework.data.repository.RepositoryDefinition;
@@ -61,7 +62,13 @@ import org.springframework.data.repository.core.RepositoryMetadata;
 import org.springframework.data.repository.core.support.RepositoryComposition.RepositoryFragments;
 import org.springframework.data.repository.core.support.RepositoryMethodInvocationListener.RepositoryMethodInvocation;
 import org.springframework.data.repository.core.support.RepositoryMethodInvocationListener.RepositoryMethodInvocationResult.State;
+import org.springframework.data.repository.query.QueryByExampleExecutor;
+import org.springframework.data.repository.query.QueryCreationException;
+import org.springframework.data.repository.query.QueryLookupStrategy;
+import org.springframework.data.repository.query.QueryMethodEvaluationContextProvider;
+import org.springframework.data.repository.query.ReactiveQueryByExampleExecutor;
 import org.springframework.data.repository.query.RepositoryQuery;
+import org.springframework.data.repository.query.parser.PartTree;
 import org.springframework.data.repository.sample.User;
 import org.springframework.lang.Nullable;
 import org.springframework.scheduling.annotation.Async;
@@ -422,6 +429,49 @@ class RepositoryFactorySupportUnitTests {
 		orderedInvocation.verify(startup).start("spring.data.repository.proxy");
 	}
 
+	@Test // GH-2341
+	void dummyRepositoryShouldsupportQuerydsl() {
+		factory.getRepository(WithQuerydsl.class, backingRepo);
+	}
+
+	@Test // GH-2341
+	void dummyRepositoryNotSupportingReactiveQuerydslShouldRaiseException() {
+		assertThatThrownBy(() -> factory.getRepository(WithReactiveQuerydsl.class, backingRepo))
+				.isInstanceOf(UnsupportedFragmentException.class).hasMessage(
+						"Repository org.springframework.data.repository.core.support.RepositoryFactorySupportUnitTests$WithReactiveQuerydsl implements org.springframework.data.repository.query.ReactiveQueryByExampleExecutor but DummyRepositoryFactory does not support Reactive Query by Example!");
+	}
+
+	@Test // GH-2341
+	void dummyRepositoryNotSupportingQbeShouldRaiseException() {
+		assertThatThrownBy(() -> factory.getRepository(WithQbe.class, backingRepo))
+				.hasMessageContaining("does not support Query by Example");
+	}
+
+	@Test // GH-2341
+	void dummyRepositoryNotSupportingReactiveQbeShouldRaiseException() {
+		assertThatThrownBy(() -> factory.getRepository(WithReactiveQbe.class, backingRepo))
+				.hasMessageContaining("does not support Reactive Query by Example");
+	}
+
+	@Test // GH-2341
+	void derivedQueryMethodCannotBeImplemented() {
+
+		DummyRepositoryFactory factory = new DummyRepositoryFactory(backingRepo) {
+			@Override
+			protected Optional<QueryLookupStrategy> getQueryLookupStrategy(QueryLookupStrategy.Key key,
+					QueryMethodEvaluationContextProvider evaluationContextProvider) {
+				return Optional.of((method, metadata, factory, namedQueries) -> {
+					new PartTree(method.getName(), method.getReturnType());
+					return null;
+				});
+			}
+		};
+
+		assertThatThrownBy(() -> factory.getRepository(WithQueryMethodUsingInvalidProperty.class))
+				.isInstanceOf(QueryCreationException.class).hasMessageContaining("findAllByName")
+				.hasMessageContaining("No property name found for type Object");
+	}
+
 	private ConvertingRepository prepareConvertingRepository(final Object expectedValue) {
 
 		when(factory.queryOne.execute(any(Object[].class))).then(invocation -> {
@@ -543,4 +593,27 @@ class RepositoryFactorySupportUnitTests {
 
 		CustomRepositoryBaseClass(EntityInformation<?, ?> information) {}
 	}
+
+	interface WithQuerydsl extends Repository<Object, Long>, QuerydslPredicateExecutor<Object> {
+
+	}
+
+	interface WithReactiveQuerydsl extends Repository<Object, Long>, ReactiveQueryByExampleExecutor<Object> {
+
+	}
+
+	interface WithQbe extends Repository<Object, Long>, QueryByExampleExecutor<Object> {
+
+	}
+
+	interface WithReactiveQbe extends Repository<Object, Long>, ReactiveQueryByExampleExecutor<Object> {
+
+	}
+
+	interface WithQueryMethodUsingInvalidProperty extends Repository<Object, Long> {
+
+		Object findAllByName();
+
+	}
+
 }