Fix/scope the Scalar filter to the Scalar starters

springdoc-openapi-starter-common/src/main/java/org/springdoc/scalar/ScalarDisableAutoConfiguration.java

@@ -37,6 +37,19 @@
 
 /**
  * Disable Scalar WebJar AutoConfiguration.
+ *
+ * <p>The class stays in this module, because it is shared by both Springdoc Scalar starters, but it
+ * is no longer registered here. This module is a dependency of every starter, so a registration
+ * here made the filter apply to applications using the Swagger UI or the API-only starter as well,
+ * leaving them with neither Scalar controller (#3387). Each Springdoc Scalar starter now declares
+ * the filter in its own {@code META-INF/spring.factories}, which keeps the duplicate registration
+ * protection of #3084 while letting the standalone Scalar integration work everywhere it is not
+ * replaced.
+ *
+ * <p>Both Scalar auto-configurations are always excluded together, by design: Scalar's own
+ * {@code ScalarWebFluxAutoConfiguration} carries no {@code @ConditionalOnWebApplication}
+ * constraint, so excluding only the matching stack would let a reactive Scalar controller be
+ * registered in a servlet application, and the other way round.
  */
 public class ScalarDisableAutoConfiguration
 		implements AutoConfigurationImportFilter {

springdoc-openapi-starter-common/src/test/java/org/springdoc/scalar/ScalarDisableAutoConfigurationTest.java

@@ -0,0 +1,80 @@
+/*
+ *
+ *  *
+ *  *  *
+ *  *  *  *
+ *  *  *  *  *
+ *  *  *  *  *  * Copyright 2019-2026 the original author or 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 org.springdoc.scalar;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.autoconfigure.AutoConfigurationImportFilter;
+import org.springframework.boot.autoconfigure.AutoConfigurationMetadata;
+import org.springframework.core.io.support.SpringFactoriesLoader;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * springdoc-openapi-starter-common is pulled in by every starter: nothing that disables Scalar's
+ * standalone autoconfiguration may be registered from here, otherwise applications using the
+ * Swagger UI or the API-only starter lose the Scalar integration with nothing replacing it (#3387).
+ * The filter itself must keep excluding both Scalar auto-configurations, since it is the guard
+ * against the duplicate registration of #3084 once a Springdoc Scalar starter declares it.
+ *
+ * @author awinishere
+ */
+class ScalarDisableAutoConfigurationTest {
+
+	private static final String FILTER_CLASS = "org.springdoc.scalar.ScalarDisableAutoConfiguration";
+
+	private static final String[] SCALAR_AUTO_CONFIGURATIONS = {
+			"com.scalar.maven.webmvc.ScalarWebMvcAutoConfiguration",
+			"com.scalar.maven.webflux.ScalarWebFluxAutoConfiguration" };
+
+	private List<String> registeredFilterNames() {
+		SpringFactoriesLoader loader = SpringFactoriesLoader
+				.forDefaultResourceLocation(getClass().getClassLoader());
+		return loader.load(AutoConfigurationImportFilter.class)
+				.stream()
+				.map(filter -> filter.getClass().getName())
+				.toList();
+	}
+
+	@Test
+	void noScalarAutoConfigurationImportFilterIsRegisteredFromThisModule() {
+
+		assertThat(registeredFilterNames()).doesNotContain(FILTER_CLASS);
+	}
+
+	@Test
+	void filterStillDisablesBothScalarAutoConfigurations() {
+
+		boolean[] matches = new ScalarDisableAutoConfiguration()
+				.match(SCALAR_AUTO_CONFIGURATIONS, (AutoConfigurationMetadata) null);
+
+		assertThat(matches).containsExactly(false, false);
+	}
+
+}

springdoc-openapi-starter-webflux-scalar/src/test/java/test/org/springdoc/webflux/scalar/ScalarStarterRegistersTheDisableFilterTest.java

@@ -0,0 +1,62 @@
+/*
+ *
+ *  *
+ *  *  *
+ *  *  *  *
+ *  *  *  *  *
+ *  *  *  *  *  * Copyright 2019-2026 the original author or 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 test.org.springdoc.webflux.scalar;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.autoconfigure.AutoConfigurationImportFilter;
+import org.springframework.core.io.support.SpringFactoriesLoader;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * The exclusion of Scalar's standalone auto-configuration belongs to the Scalar starters: it is
+ * only legitimate where a Springdoc Scalar controller replaces it (#3387). It is declared in this
+ * module {@code META-INF/spring.factories}, and not in springdoc-openapi-starter-common, so that
+ * it is loaded exactly when this starter is installed.
+ *
+ * @author awinishere
+ */
+class ScalarStarterRegistersTheDisableFilterTest {
+
+	@Test
+	void scalarStarterDisablesTheStandaloneAutoConfiguration() {
+
+		SpringFactoriesLoader loader = SpringFactoriesLoader
+				.forDefaultResourceLocation(getClass().getClassLoader());
+
+		List<String> registeredFilters = loader.load(AutoConfigurationImportFilter.class)
+				.stream()
+				.map(filter -> filter.getClass().getName())
+				.toList();
+
+		assertThat(registeredFilters).contains("org.springdoc.scalar.ScalarDisableAutoConfiguration");
+	}
+
+}

springdoc-openapi-starter-webmvc-scalar/src/main/resources/META-INF/spring.factories

@@ -0,0 +1,2 @@
+org.springframework.boot.autoconfigure.AutoConfigurationImportFilter=\
+org.springdoc.scalar.ScalarDisableAutoConfiguration

springdoc-openapi-starter-webmvc-scalar/src/test/java/test/org/springdoc/webmvc/scalar/ScalarStarterRegistersTheDisableFilterTest.java

@@ -0,0 +1,62 @@
+/*
+ *
+ *  *
+ *  *  *
+ *  *  *  *
+ *  *  *  *  *
+ *  *  *  *  *  * Copyright 2019-2026 the original author or 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 test.org.springdoc.webmvc.scalar;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.autoconfigure.AutoConfigurationImportFilter;
+import org.springframework.core.io.support.SpringFactoriesLoader;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * The exclusion of Scalar's standalone autoconfiguration belongs to the Scalar starters: it is
+ * only legitimate where a Springdoc Scalar controller replaces it (#3387). It is declared in this
+ * module {@code META-INF/spring.factories}, and not in springdoc-openapi-starter-common, so that
+ * it is loaded exactly when this starter is installed.
+ *
+ * @author awinishere
+ */
+class ScalarStarterRegistersTheDisableFilterTest {
+
+	@Test
+	void scalarStarterDisablesTheStandaloneAutoConfiguration() {
+
+		SpringFactoriesLoader loader = SpringFactoriesLoader
+				.forDefaultResourceLocation(getClass().getClassLoader());
+
+		List<String> registeredFilters = loader.load(AutoConfigurationImportFilter.class)
+				.stream()
+				.map(filter -> filter.getClass().getName())
+				.toList();
+
+		assertThat(registeredFilters).contains("org.springdoc.scalar.ScalarDisableAutoConfiguration");
+	}
+
+}

springdoc-openapi-starter-webmvc-scalar/src/test/java/test/org/springdoc/webmvc/scalar/app20/SpringDocApp20Test.java

@@ -0,0 +1,70 @@
+/*
+ *
+ *  *
+ *  *  *
+ *  *  *  *
+ *  *  *  *  *
+ *  *  *  *  *  * Copyright 2019-2026 the original author or 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 test.org.springdoc.webmvc.scalar.app20;
+
+import com.scalar.maven.webmvc.ScalarWebMvcAutoConfiguration;
+import com.scalar.maven.webmvc.ScalarWebMvcController;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.ApplicationContext;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * The Springdoc Scalar starter and Scalar's own integration both declare a bean named
+ * {@code scalarWebMvcController} mapped to {@code ${scalar.path}}: the standalone one must not
+ * survive next to the Springdoc controller, otherwise the application fails on a duplicated bean
+ * definition (#3084). This is the counterpart of the standalone Scalar support restored by #3387.
+ *
+ * @author awinishere
+ */
+@SpringBootTest
+class SpringDocApp20Test {
+
+	@Autowired
+	private ApplicationContext context;
+
+	@Test
+	void scalarStandaloneAutoConfigurationIsNotApplied() {
+
+		assertThat(context.getBeanNamesForType(ScalarWebMvcAutoConfiguration.class)).isEmpty();
+		assertThat(context.getBeanNamesForType(ScalarWebMvcController.class)).isEmpty();
+	}
+
+	@Test
+	void springdocScalarControllerReplacesIt() {
+
+		assertThat(context.getBean("scalarWebMvcController"))
+				.isInstanceOf(org.springdoc.webmvc.scalar.ScalarWebMvcController.class);
+	}
+
+	@SpringBootApplication
+	static class SpringDocTestApp {}
+}