From a6a9fcd84c9d2a2e51a653ff2e33f4a57b84dc7c Mon Sep 17 00:00:00 2001
From: Georgios Andrianakis <geoand@gmail.com>
Date: Thu, 29 Jun 2023 13:20:02 +0300
Subject: [PATCH] Improve generic resolution support in Spring Data JPA

Fixes: #34350
---
 .../deployment/generate/DerivedMethodsAdder.java | 16 ++++++++++++----
 .../data/jpa/IntermediatePostRepository.java     |  2 +-
 .../it/spring/data/jpa/PostRepository.java       |  2 +-
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/extensions/spring-data-jpa/deployment/src/main/java/io/quarkus/spring/data/deployment/generate/DerivedMethodsAdder.java b/extensions/spring-data-jpa/deployment/src/main/java/io/quarkus/spring/data/deployment/generate/DerivedMethodsAdder.java
index 0fd83bbf1abde..7be969bce4be2 100644
--- a/extensions/spring-data-jpa/deployment/src/main/java/io/quarkus/spring/data/deployment/generate/DerivedMethodsAdder.java
+++ b/extensions/spring-data-jpa/deployment/src/main/java/io/quarkus/spring/data/deployment/generate/DerivedMethodsAdder.java
@@ -297,12 +297,20 @@ private Type extractResultType(ClassInfo repositoryClassInfo, MethodInfo method)
             // this is accomplished by resolving the generic type from the interface we are actually implementing
             TypeVariable resultTypeVariable = resultType.asTypeVariable();
             List<TypeVariable> interfaceTypeVariables = method.declaringClass().typeParameters();
-            if (interfaceTypeVariables.size() == 1 && interfaceTypeVariables.get(0)
-                    .equals(resultTypeVariable)) {
+
+            int matchingIndex = -1;
+            for (int i = 0; i < interfaceTypeVariables.size(); i++) {
+                if (interfaceTypeVariables.get(i).equals(resultTypeVariable)) {
+                    matchingIndex = i;
+                    break;
+                }
+            }
+
+            if (matchingIndex != -1) {
                 List<Type> resolveTypeParameters = JandexUtil.resolveTypeParameters(repositoryClassInfo.name(),
                         method.declaringClass().name(), index);
-                if (resolveTypeParameters.size() == 1) {
-                    return resolveTypeParameters.get(0);
+                if (matchingIndex < resolveTypeParameters.size()) {
+                    return resolveTypeParameters.get(matchingIndex);
                 }
             }
         }
diff --git a/integration-tests/spring-data-jpa/src/main/java/io/quarkus/it/spring/data/jpa/IntermediatePostRepository.java b/integration-tests/spring-data-jpa/src/main/java/io/quarkus/it/spring/data/jpa/IntermediatePostRepository.java
index 733757e3191fc..f2d6a7ed8e506 100644
--- a/integration-tests/spring-data-jpa/src/main/java/io/quarkus/it/spring/data/jpa/IntermediatePostRepository.java
+++ b/integration-tests/spring-data-jpa/src/main/java/io/quarkus/it/spring/data/jpa/IntermediatePostRepository.java
@@ -9,7 +9,7 @@
  * Used to ensure that entity relationships work correctly
  */
 @NoRepositoryBean
-public interface IntermediatePostRepository<T extends ByPassHolder> extends BypassHolderRepository<T, Long> {
+public interface IntermediatePostRepository<UNUSED1, T extends ByPassHolder, UNUSED2> extends BypassHolderRepository<T, Long> {
 
     List<T> findByPostedBefore(ZonedDateTime zdt);
 }
diff --git a/integration-tests/spring-data-jpa/src/main/java/io/quarkus/it/spring/data/jpa/PostRepository.java b/integration-tests/spring-data-jpa/src/main/java/io/quarkus/it/spring/data/jpa/PostRepository.java
index 643420fd825f3..0c3d7494e54ba 100644
--- a/integration-tests/spring-data-jpa/src/main/java/io/quarkus/it/spring/data/jpa/PostRepository.java
+++ b/integration-tests/spring-data-jpa/src/main/java/io/quarkus/it/spring/data/jpa/PostRepository.java
@@ -5,7 +5,7 @@
 /**
  * Used to ensure that entity relationships work correctly
  */
-public interface PostRepository extends IntermediatePostRepository<Post> {
+public interface PostRepository extends IntermediatePostRepository<Object, Post, Object> {
 
     List<Post> findAllByOrganization(String organization);