test: reproduce nullable Java component references

springdoc-openapi-starter-webmvc-api/src/test/java/test/org/springdoc/api/v30/app273/NullableReferenceController.java

@@ -0,0 +1,42 @@
+/*
+ * 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.api.v30.app273;
+
+import jakarta.annotation.Nullable;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * Controller exposing a nullable Java component reference.
+ *
+ * @author Janek Lasocki-Biczysko
+ */
+@RestController
+public class NullableReferenceController {
+
+	@GetMapping("/nullable-reference")
+	public NullableReferenceResponse getNullableReference() {
+		return new NullableReferenceResponse(null);
+	}
+
+	public record NullableReferenceResponse(@Nullable NullableReferenceChild child) {
+	}
+
+	public record NullableReferenceChild(String value) {
+	}
+}

springdoc-openapi-starter-webmvc-api/src/test/java/test/org/springdoc/api/v30/app273/SpringDocApp273Test.java

@@ -0,0 +1,50 @@
+/*
+ * 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.api.v30.app273;
+
+import org.junit.jupiter.api.Test;
+import org.springdoc.core.utils.Constants;
+import test.org.springdoc.api.AbstractCommonTest;
+
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.test.context.TestPropertySource;
+
+import static org.hamcrest.Matchers.is;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+/**
+ * Verifies that nullability for a Java component reference is scoped to its property.
+ *
+ * @author Janek Lasocki-Biczysko
+ */
+@TestPropertySource(properties = { "springdoc.api-docs.version=openapi_3_0" })
+public class SpringDocApp273Test extends AbstractCommonTest {
+
+	@Test
+	void nullableJavaComponentReferenceIsScopedToTheProperty() throws Exception {
+		mockMvc.perform(get(Constants.DEFAULT_API_DOCS_URL)).andExpect(status().isOk())
+				.andExpect(jsonPath("$.components.schemas.NullableReferenceResponse.properties.child.nullable", is(true)))
+				.andExpect(jsonPath("$.components.schemas.NullableReferenceResponse.properties.child.allOf[0]['$ref']",
+						is("#/components/schemas/NullableReferenceChild")));
+	}
+
+	@SpringBootApplication
+	static class SpringDocTestApp {
+	}
+}