From 3ed2fe3468f6c491c064470054ab89b4e8fc94e4 Mon Sep 17 00:00:00 2001
From: Subin Kim <rla0010101@gmail.com>
Date: Sat, 6 Sep 2025 02:02:04 +0900
Subject: [PATCH] Fix: findByIdOrNull ignores AOP annotations on overridden
 methods.

The findByIdOrNull Kotlin extension was not declared as an inline
function. This caused the call to bind to the generic
CrudRepository.findById(Object) method at compile time, bypassing
any AOP proxies on user-overridden repository methods with specific
types like findById(String).

By declaring the extension as inline, the function body is inlined at
the call site. This ensures that the compiler resolves the call to the
most specific, user-defined findById method, allowing AOP proxies for
features like caching or entity graphs to be correctly applied.

Signed-off-by: Subin Kim <rla0010101@gmail.com>
---
 .../repository/CrudRepositoryExtensions.kt    |  3 ++-
 .../CrudRepositoryExtensionsTests.kt          | 26 ++++++++++++++++++-
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/src/main/kotlin/org/springframework/data/repository/CrudRepositoryExtensions.kt b/src/main/kotlin/org/springframework/data/repository/CrudRepositoryExtensions.kt
index f6eb459740..7835560ec9 100644
--- a/src/main/kotlin/org/springframework/data/repository/CrudRepositoryExtensions.kt
+++ b/src/main/kotlin/org/springframework/data/repository/CrudRepositoryExtensions.kt
@@ -22,6 +22,7 @@ package org.springframework.data.repository
  * @return the entity with the given id or `null` if none found.
  * @author Sebastien Deleuze
  * @author Oscar Hernandez
+ * @author Subin Kim
  * @since 2.1.4
  */
-fun <T: Any, ID: Any> CrudRepository<T, ID>.findByIdOrNull(id: ID): T? = findById(id).orElse(null)
+inline fun <T: Any, ID: Any> CrudRepository<T, ID>.findByIdOrNull(id: ID): T? = findById(id).orElse(null)
diff --git a/src/test/kotlin/org/springframework/data/repository/CrudRepositoryExtensionsTests.kt b/src/test/kotlin/org/springframework/data/repository/CrudRepositoryExtensionsTests.kt
index bcf68f92a1..ecf1f49445 100644
--- a/src/test/kotlin/org/springframework/data/repository/CrudRepositoryExtensionsTests.kt
+++ b/src/test/kotlin/org/springframework/data/repository/CrudRepositoryExtensionsTests.kt
@@ -18,8 +18,9 @@ package org.springframework.data.repository
 import io.mockk.every
 import io.mockk.mockk
 import io.mockk.verify
-import org.assertj.core.api.Assertions.assertThat
+import org.assertj.core.api.Assertions.*
 import org.junit.jupiter.api.Test
+import org.springframework.aop.framework.ProxyFactory
 import org.springframework.data.repository.sample.User
 import java.util.*
 
@@ -28,9 +29,14 @@ import java.util.*
  *
  * @author Sebastien Deleuze
  * @author Mark Paluch
+ * @author Subin Kim
  */
 class CrudRepositoryExtensionsTests {
 
+    private interface UserRepository : CrudRepository<User, String> {
+        override fun findById(id: String): Optional<User>
+    }
+
 	var repository = mockk<CrudRepository<User, String>>()
 
 	@Test // DATACMNS-1346
@@ -44,4 +50,22 @@ class CrudRepositoryExtensionsTests {
 		assertThat(repository.findByIdOrNull("foo")).isNull()
 		verify(exactly = 2) { repository.findById("foo") }
 	}
+
+    @Test // GH-3326
+    fun `findByIdOrNull should trigger AOP proxy on overridden method`() {
+
+        val mockTarget = mockk<UserRepository>()
+        val user = User()
+        every { mockTarget.findById("1") } returns Optional.of(user)
+
+        val factory = ProxyFactory()
+        factory.setTarget(mockTarget)
+        factory.addInterface(UserRepository::class.java)
+        val proxy = factory.proxy as UserRepository
+
+        val result = proxy.findByIdOrNull("1")
+        assertThat(result).isEqualTo(user)
+
+        verify(exactly = 1) { mockTarget.findById("1") }
+    }
 }