Fix application startup failure with springdoc.show-actuator=true and a separate management port

ff4j-spring-boot-autoconfigure-common/pom.xml

@@ -58,6 +58,16 @@
       <artifactId>spring-boot-starter-test</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-actuator</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-web</artifactId>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
   <build>
     <finalName>${project.artifactId}</finalName>

ff4j-spring-boot-autoconfigure-common/src/main/kotlin/org/ff4j/spring/boot/autoconfigure/common/FF4JOpenApiConfiguration.kt

@@ -24,34 +24,52 @@ import org.slf4j.LoggerFactory
 import org.springdoc.core.configuration.SpringDocConfiguration
 import org.springdoc.core.models.GroupedOpenApi
 import org.springdoc.core.properties.SpringDocConfigProperties
+import org.springframework.beans.factory.InitializingBean
+import org.springframework.beans.factory.ObjectProvider
 import org.springframework.boot.autoconfigure.AutoConfiguration
 import org.springframework.boot.autoconfigure.AutoConfigureAfter
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty
+import org.springframework.boot.context.properties.bind.Binder
 import org.springframework.context.annotation.Bean
+import org.springframework.core.env.Environment
 
+/**
+ * This configuration must remain instantiable with a default constructor and must not rely on
+ * autowired state: when `springdoc.show-actuator=true` and the management port differs from the
+ * server port, springdoc registers a BeanFactoryPostProcessor depending on all [GroupedOpenApi]
+ * beans, so this class is instantiated before autowiring and configuration-properties binding
+ * are available.
+ */
 @AutoConfiguration
 @AutoConfigureAfter(FF4JConfiguration::class, SpringDocConfiguration::class)
 @ConditionalOnClass(SpringDocConfiguration::class)
-class FF4JOpenApiConfiguration(
-  private val config: FF4JConfigurationProperties,
-  private val springDocConfigProperties: SpringDocConfigProperties = SpringDocConfigProperties()
-) {
+class FF4JOpenApiConfiguration {
 
   private val log: Logger = LoggerFactory.getLogger(FF4JOpenApiConfiguration::class.java)
 
-  init {
-    if (!config.api.springDoc.enabled) {
-      log.info("Exclude FF4J OpenAPI configuration")
-      springDocConfigProperties.pathsToExclude = listOf("${config.api.contextPath}/**")
-    }
-  }
-
   @Bean
   @ConditionalOnProperty(name = ["ff4j.api.spring-doc.enabled"], havingValue = "true", matchIfMissing = false)
-  fun groupApiEnabled(springDocConfigProperties: SpringDocConfigProperties): GroupedOpenApi {
+  fun groupApiEnabled(environment: Environment): GroupedOpenApi {
     log.info("Initializing FF4J GroupedOpenApi configuration")
+    // Bind from the Environment instead of injecting FF4JConfigurationProperties: this bean can be
+    // created during the BeanFactoryPostProcessor phase, where the properties bean would exist but
+    // never get bound (ConfigurationPropertiesBindingPostProcessor is not registered yet).
+    val config = Binder.get(environment)
+      .bindOrCreate("ff4j", FF4JConfigurationProperties::class.java)
     return GroupedOpenApi.builder().group(config.api.springDoc.group).pathsToMatch("${config.api.contextPath}/**")
       .build()
   }
+
+  @Bean
+  @ConditionalOnProperty(name = ["ff4j.api.spring-doc.enabled"], havingValue = "false", matchIfMissing = true)
+  fun ff4jOpenApiPathsExclusion(
+    config: FF4JConfigurationProperties,
+    springDocConfigProperties: ObjectProvider<SpringDocConfigProperties>
+  ): InitializingBean = InitializingBean {
+    springDocConfigProperties.ifAvailable {
+      log.info("Exclude FF4J OpenAPI configuration")
+      it.pathsToExclude = listOf("${config.api.contextPath}/**")
+    }
+  }
 }

ff4j-spring-boot-autoconfigure-common/src/test/kotlin/org/ff4j/spring/boot/autoconfigure/common/FF4JOpenApiActuatorConfigurationTest.kt

@@ -0,0 +1,54 @@
+/*-
+ * #%L
+ * ff4j-spring-boot-autoconfigure-common
+ * %%
+ * Copyright (C) 2013 - 2026 FF4J
+ * %%
+ * 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
+ *
+ *      http://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.
+ * #L%
+ */
+package org.ff4j.spring.boot.autoconfigure.common
+
+import org.assertj.core.api.Assertions
+import org.junit.jupiter.api.Test
+import org.springdoc.core.models.GroupedOpenApi
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.boot.test.context.SpringBootTest
+import org.springframework.test.context.TestPropertySource
+
+/**
+ * Reproduces GH issue: with `springdoc.show-actuator=true` and a management port
+ * different from the server port, springdoc registers a BeanFactoryPostProcessor
+ * depending on all GroupedOpenApi beans, forcing early instantiation of
+ * FF4JOpenApiConfiguration before autowiring infrastructure is ready.
+ */
+@SpringBootTest(classes = [Application::class])
+@TestPropertySource(
+  properties = [
+    "ff4j.api.spring-doc.enabled=true",
+    "ff4j.api.spring-doc.group=ff4j-custom-group",
+    "springdoc.show-actuator=true",
+    "server.port=8080",
+    "management.server.port=9090"
+  ]
+)
+class FF4JOpenApiActuatorConfigurationTest {
+
+  @Autowired
+  private lateinit var groupedOpenApi: GroupedOpenApi
+
+  @Test
+  fun testBootWithActuatorOnDifferentPort() {
+    Assertions.assertThat(groupedOpenApi.group).isEqualTo("ff4j-custom-group")
+  }
+}