DTO joins support issues

data-processor/src/main/java/io/micronaut/data/processor/visitors/finders/AbstractCriteriaMethodMatch.java

@@ -792,11 +792,12 @@ private boolean isDtoType(ClassElement repositoryElement, ClassElement classElem
     /**
      * Find DTO properties.
      *
+     * @param matchContext The method match context
      * @param entity     The entity
      * @param returnType The result
      * @return DTO properties
      */
-    protected List<SourcePersistentProperty> getDtoProjectionProperties(SourcePersistentEntity entity,
+    protected List<SourcePersistentProperty> getDtoProjectionProperties(MethodMatchContext matchContext, SourcePersistentEntity entity,
                                                                         ClassElement returnType) {
         return returnType.getBeanProperties().stream()
             .filter(dtoProperty -> {
@@ -825,8 +826,13 @@ protected List<SourcePersistentProperty> getDtoProjectionProperties(SourcePersis
                     // Convert anything to a string or an object
                     return pp;
                 }
-                if (!TypeUtils.areTypesCompatible(dtoPropertyType, pp.getType())) {
-                    throw new MatchFailedException("Property [" + propertyName + "] of type [" + dtoPropertyType.getName() + "] is not compatible with equivalent property of type [" + pp.getType().getName() + "] declared in entity: " + entity.getName());
+                boolean compatibleTypes = TypeUtils.areTypesCompatible(dtoPropertyType, pp.getType());
+                if (!compatibleTypes) {
+                    // Check if these are compatible non-simple field types (kind of nested DTOs)
+                    List<SourcePersistentProperty> props = getDtoProjectionProperties(matchContext, new SourcePersistentEntity(pp.getType(), matchContext::getEntity), dtoPropertyType);
+                    if (props.isEmpty()) {
+                        throw new MatchFailedException("Property [" + propertyName + "] of type [" + dtoPropertyType.getName() + "] is not compatible with equivalent property of type [" + pp.getType().getName() + "] declared in entity: " + entity.getName());
+                    }
                 }
                 return pp;
             }).toList();

data-processor/src/main/java/io/micronaut/data/processor/visitors/finders/criteria/DeleteCriteriaMethodMatch.java

@@ -150,7 +150,7 @@ protected MethodMatchInfo build(MethodMatchContext matchContext) {
         );
 
         if (result.isDto() && !result.isRuntimeDtoConversion()) {
-            List<SourcePersistentProperty> dtoProjectionProperties = getDtoProjectionProperties(matchContext.getRootEntity(), resultType);
+            List<SourcePersistentProperty> dtoProjectionProperties = getDtoProjectionProperties(matchContext, matchContext.getRootEntity(), resultType);
             if (!dtoProjectionProperties.isEmpty()) {
                 List<Selection<?>> selectionList = dtoProjectionProperties.stream()
                     .map(p -> {

data-processor/src/main/java/io/micronaut/data/processor/visitors/finders/criteria/QueryCriteriaMethodMatch.java

@@ -160,7 +160,7 @@ protected MethodMatchInfo build(MethodMatchContext matchContext) {
         );
 
         if (result.isDto() && !result.isRuntimeDtoConversion()) {
-            List<SourcePersistentProperty> dtoProjectionProperties = getDtoProjectionProperties(matchContext.getRootEntity(), resultType);
+            List<SourcePersistentProperty> dtoProjectionProperties = getDtoProjectionProperties(matchContext, matchContext.getRootEntity(), resultType);
             if (!dtoProjectionProperties.isEmpty()) {
                 Root<?> root = query.getRoots().iterator().next();
                 List<Selection<?>> selectionList = dtoProjectionProperties.stream()

data-processor/src/main/java/io/micronaut/data/processor/visitors/finders/criteria/UpdateCriteriaMethodMatch.java

@@ -178,7 +178,7 @@ protected MethodMatchInfo build(MethodMatchContext matchContext) {
         );
 
         if (result.isDto() && !result.isRuntimeDtoConversion()) {
-            List<SourcePersistentProperty> dtoProjectionProperties = getDtoProjectionProperties(matchContext.getRootEntity(), resultType);
+            List<SourcePersistentProperty> dtoProjectionProperties = getDtoProjectionProperties(matchContext, matchContext.getRootEntity(), resultType);
             if (!dtoProjectionProperties.isEmpty()) {
                 List<Selection<?>> selectionList = dtoProjectionProperties.stream()
                     .map(p -> {

data-tck/src/main/groovy/io/micronaut/data/tck/tests/AbstractRepositorySpec.groovy

@@ -48,9 +48,7 @@ import io.micronaut.data.tck.entities.Person
 import io.micronaut.data.tck.entities.Student
 import io.micronaut.data.tck.entities.TimezoneBasicTypes
 import io.micronaut.data.tck.jdbc.entities.Role
-import io.micronaut.data.tck.jdbc.entities.User
 import io.micronaut.data.tck.jdbc.entities.UserRole
-import io.micronaut.data.tck.jdbc.entities.UserRoleId
 import io.micronaut.data.tck.repositories.*
 import io.micronaut.transaction.SynchronousTransactionManager
 import io.micronaut.transaction.TransactionCallback
@@ -1332,6 +1330,18 @@ abstract class AbstractRepositorySpec extends Specification {
             authors.forEach { assert it.books.size() == 0 }
     }
 
+    void "test DTO with nested DTO"() {
+        given:
+        saveSampleBooks()
+
+        when:
+        def optBook = bookRepository.queryByTitleContains("Stand")
+
+        then:
+        optBook.present
+        optBook.get().author
+    }
+
     void "stream joined"() {
         if (!transactionManager.isPresent()) {
             return

data-tck/src/main/java/io/micronaut/data/tck/entities/BookDtoWithAuthorDto.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2017-2020 original authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.micronaut.data.tck.entities;
+
+import io.micronaut.core.annotation.Introspected;
+
+import java.time.LocalDateTime;
+
+@Introspected
+public class BookDtoWithAuthorDto {
+
+    private String title;
+    private int totalPages;
+    private LocalDateTime lastUpdated;
+
+    private AuthorDTO author;
+
+    public BookDtoWithAuthorDto() {
+    }
+
+    public BookDtoWithAuthorDto(String title, int totalPages) {
+        this.title = title;
+        this.totalPages = totalPages;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public int getTotalPages() {
+        return totalPages;
+    }
+
+    public void setTotalPages(int totalPages) {
+        this.totalPages = totalPages;
+    }
+
+    public LocalDateTime getLastUpdated() {
+        return lastUpdated;
+    }
+
+    public void setLastUpdated(LocalDateTime lastUpdated) {
+        this.lastUpdated = lastUpdated;
+    }
+
+    public AuthorDTO getAuthor() {
+        return author;
+    }
+
+    public void setAuthor(AuthorDTO author) {
+        this.author = author;
+    }
+}

data-tck/src/main/java/io/micronaut/data/tck/repositories/BookRepository.java

@@ -33,6 +33,7 @@
 import io.micronaut.data.tck.entities.AuthorBooksDto;
 import io.micronaut.data.tck.entities.Book;
 import io.micronaut.data.tck.entities.BookDto;
+import io.micronaut.data.tck.entities.BookDtoWithAuthorDto;
 import io.micronaut.data.tck.entities.Genre;
 
 import java.util.ArrayList;
@@ -172,4 +173,6 @@ protected Book newBook(Author author, String title, int pages) {
     abstract List<Book> findByTitleInAndTotalPagesGreaterThan(List<String> titles, int totalPages);
 
     abstract Long countByTitleInAndTotalPagesGreaterThan(List<String> titles, int totalPages);
+
+    abstract Optional<BookDtoWithAuthorDto> queryByTitleContains(String title);
 }