More sophisticated fix (thanks to stefv from SO)

gameyfin/build.gradle.kts

@@ -100,6 +100,10 @@ tasks.register<Jar>("uberJar") {
     from({
         configurations.runtimeClasspath.get().filter { it.name.endsWith("jar") }.map { zipTree(it) }
     })
+
+    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+    isZip64 = true
+
     manifest {
         attributes["Main-Class"] = appMainClass
     }

gameyfin/src/main/kotlin/de/grimsi/gameyfin/GameyfinApplication.kt

@@ -12,6 +12,5 @@ import org.springframework.transaction.annotation.EnableTransactionManagement
 class GameyfinApplication
 
 fun main(args: Array<String>) {
-    System.setProperty("spring.devtools.restart.enabled", "false");
     runApplication<GameyfinApplication>(*args)
 }

gameyfin/src/main/kotlin/de/grimsi/gameyfin/core/plugins/PluginManagerConfig.kt

@@ -1,7 +1,6 @@
-package de.grimsi.gameyfin.core
+package de.grimsi.gameyfin.core.plugins
 
 import io.github.oshai.kotlinlogging.KotlinLogging
-import org.pf4j.DefaultPluginManager
 import org.springframework.boot.context.event.ApplicationReadyEvent
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
@@ -14,7 +13,7 @@ class PluginManagerConfig {
     private val pluginPath = Path.of("plugins")
 
     @Bean
-    fun pluginManager() = DefaultPluginManager(pluginPath)
+    fun pluginManager() = SpringDevtoolsPluginManager(pluginPath)
 
     @EventListener(ApplicationReadyEvent::class)
     fun loadedPlugins() {

gameyfin/src/main/kotlin/de/grimsi/gameyfin/core/plugins/SpringDevtoolsDevelopmentPluginLoader.kt

@@ -0,0 +1,20 @@
+package de.grimsi.gameyfin.core.plugins
+
+import org.pf4j.DevelopmentPluginLoader
+import org.pf4j.PluginClassLoader
+import org.pf4j.PluginDescriptor
+import org.pf4j.PluginManager
+import java.nio.file.Path
+
+/**
+ * @see https://stackoverflow.com/questions/73654174/my-application-cant-find-the-extension-with-pf4j
+ */
+class SpringDevtoolsDevelopmentPluginLoader(
+    pluginManager: PluginManager,
+    private val parentClassLoader: ClassLoader
+) : DevelopmentPluginLoader(pluginManager) {
+
+    override fun createPluginClassLoader(pluginPath: Path, pluginDescriptor: PluginDescriptor): PluginClassLoader {
+        return PluginClassLoader(pluginManager, pluginDescriptor, parentClassLoader)
+    }
+}

gameyfin/src/main/kotlin/de/grimsi/gameyfin/core/plugins/SpringDevtoolsPluginManager.kt

@@ -0,0 +1,38 @@
+package de.grimsi.gameyfin.core.plugins
+
+import org.pf4j.CompoundPluginLoader
+import org.pf4j.CompoundPluginRepository
+import org.pf4j.DefaultPluginLoader
+import org.pf4j.DefaultPluginManager
+import org.pf4j.DefaultPluginRepository
+import org.pf4j.DevelopmentPluginRepository
+import org.pf4j.JarPluginLoader
+import org.pf4j.JarPluginRepository
+import org.pf4j.PluginLoader
+import org.pf4j.PluginRepository
+import java.nio.file.Path
+
+/**
+ * @see https://stackoverflow.com/questions/73654174/my-application-cant-find-the-extension-with-pf4j
+ */
+class SpringDevtoolsPluginManager(path: Path) : DefaultPluginManager(path) {
+
+    override fun createPluginRepository(): PluginRepository {
+        return CompoundPluginRepository()
+            .add(DevelopmentPluginRepository(pluginsRoots), this::isDevelopment)
+            .add(JarPluginRepository(pluginsRoots), this::isNotDevelopment)
+            .add(DefaultPluginRepository(pluginsRoots), this::isNotDevelopment)
+    }
+
+    override fun createPluginLoader(): PluginLoader {
+        val compoundPluginLoader = CompoundPluginLoader()
+        val developmentPluginLoader = SpringDevtoolsDevelopmentPluginLoader(this, javaClass.classLoader)
+        val jarPluginLoader = JarPluginLoader(this)
+        val defaultPluginLoader = DefaultPluginLoader(this)
+
+        return compoundPluginLoader
+            .add(developmentPluginLoader, this::isDevelopment)
+            .add(jarPluginLoader, this::isNotDevelopment)
+            .add(defaultPluginLoader, this::isNotDevelopment)
+    }
+}

gameyfin/src/main/kotlin/de/grimsi/gameyfin/games/Game.kt

@@ -1,13 +1,12 @@
 package de.grimsi.gameyfin.games
 
 import jakarta.persistence.*
-import java.nio.file.Path
 
 @Entity
 class Game(
     @Id
     @GeneratedValue(strategy = GenerationType.AUTO)
-    val id: Long? = null,
+    var id: Long? = null,
 
     val title: String,
 

gameyfin/src/main/kotlin/de/grimsi/gameyfin/games/GameRepository.kt

@@ -2,4 +2,6 @@ package de.grimsi.gameyfin.games
 
 import org.springframework.data.jpa.repository.JpaRepository
 
-interface GameRepository : JpaRepository<Game, Long>
+interface GameRepository : JpaRepository<Game, Long> {
+    fun findByPath(path: String): Game?
+}

gameyfin/src/main/kotlin/de/grimsi/gameyfin/games/GameService.kt

@@ -18,6 +18,9 @@ class GameService(
         get() = pluginManager.getExtensions(GameMetadataFetcher::class.java)
 
     fun createOrUpdate(game: Game): Game {
+        gameRepository.findByPath(game.path)?.let {
+            game.id = it.id
+        }
         return gameRepository.save(game)
     }
 
@@ -50,7 +53,7 @@ class GameService(
         }
 
         return GameDto(
-            id = game.id,
+            id = game.id!!,
             title = game.title
         )
     }