v2.8.1 - ClassCastException with spring-data-rest and openapi version 3.1

[zyro23]

Describe the bug

this is a follow-up to #2516 which is closed already but it seems the described issue still appears.

using v2.8.1 (and the new default open api version 3.1) with spring-data-rest throws a ClassCastException when trying to access swagger-ui:

2025-01-10T09:27:40.809+01:00 ERROR 24940 --- [demo] [nio-8080-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed: java.lang.ClassCastException: class io.swagger.v3.oas.models.media.JsonSchema cannot be cast to class io.swagger.v3.oas.models.media.ArraySchema (io.swagger.v3.oas.models.media.JsonSchema and io.swagger.v3.oas.models.media.ArraySchema are in unnamed module of loader 'app')] with root cause

java.lang.ClassCastException: class io.swagger.v3.oas.models.media.JsonSchema cannot be cast to class io.swagger.v3.oas.models.media.ArraySchema (io.swagger.v3.oas.models.media.JsonSchema and io.swagger.v3.oas.models.media.ArraySchema are in unnamed module of loader 'app')
	at org.springdoc.core.utils.SpringDocDataRestUtils.updateResponseSchemaEmbedded(SpringDocDataRestUtils.java:293) ~[springdoc-openapi-starter-common-2.8.1.jar:2.8.1]
	at org.springdoc.core.utils.SpringDocDataRestUtils.updateResponseSchema(SpringDocDataRestUtils.java:276) ~[springdoc-openapi-starter-common-2.8.1.jar:2.8.1]
	at org.springdoc.core.utils.SpringDocDataRestUtils.lambda$updateApiResponse$3(SpringDocDataRestUtils.java:171) ~[springdoc-openapi-starter-common-2.8.1.jar:2.8.1]
	at java.base/java.util.HashMap$KeySet.forEach(HashMap.java:1016) ~[na:na]
	at org.springdoc.core.utils.SpringDocDataRestUtils.lambda$updateApiResponse$4(SpringDocDataRestUtils.java:169) ~[springdoc-openapi-starter-common-2.8.1.jar:2.8.1]
	at java.base/java.util.LinkedHashMap$LinkedValues.forEach(LinkedHashMap.java:833) ~[na:na]
	at org.springdoc.core.utils.SpringDocDataRestUtils.updateApiResponse(SpringDocDataRestUtils.java:164) ~[springdoc-openapi-starter-common-2.8.1.jar:2.8.1]
	at org.springdoc.core.utils.SpringDocDataRestUtils.lambda$customise$0(SpringDocDataRestUtils.java:148) ~[springdoc-openapi-starter-common-2.8.1.jar:2.8.1]
	at java.base/java.util.LinkedHashMap.forEach(LinkedHashMap.java:986) ~[na:na]
	at org.springdoc.core.utils.SpringDocDataRestUtils.lambda$customise$1(SpringDocDataRestUtils.java:148) ~[springdoc-openapi-starter-common-2.8.1.jar:2.8.1]
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596) ~[na:na]
	at org.springdoc.core.utils.SpringDocDataRestUtils.lambda$customise$2(SpringDocDataRestUtils.java:143) ~[springdoc-openapi-starter-common-2.8.1.jar:2.8.1]
	at java.base/java.util.Iterator.forEachRemaining(Iterator.java:133) ~[na:na]
	at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1939) ~[na:na]
	at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:762) ~[na:na]
	at org.springdoc.core.utils.SpringDocDataRestUtils.customise(SpringDocDataRestUtils.java:141) ~[springdoc-openapi-starter-common-2.8.1.jar:2.8.1]
	at org.springdoc.core.providers.SpringRepositoryRestResourceProvider.customize(SpringRepositoryRestResourceProvider.java:292) ~[springdoc-openapi-starter-common-2.8.1.jar:2.8.1]
	at org.springdoc.webmvc.api.OpenApiResource.lambda$getPaths$1(OpenApiResource.java:159) ~[springdoc-openapi-starter-webmvc-api-2.8.1.jar:2.8.1]
	at java.base/java.util.Optional.ifPresent(Optional.java:178) ~[na:na]
	at org.springdoc.webmvc.api.OpenApiResource.lambda$getPaths$2(OpenApiResource.java:156) ~[springdoc-openapi-starter-webmvc-api-2.8.1.jar:2.8.1]
	at java.base/java.util.Optional.ifPresent(Optional.java:178) ~[na:na]
	at org.springdoc.webmvc.api.OpenApiResource.getPaths(OpenApiResource.java:152) ~[springdoc-openapi-starter-webmvc-api-2.8.1.jar:2.8.1]
	at org.springdoc.api.AbstractOpenApiResource.getOpenApi(AbstractOpenApiResource.java:370) ~[springdoc-openapi-starter-common-2.8.1.jar:2.8.1]
	at org.springdoc.webmvc.api.OpenApiResource.openapiJson(OpenApiResource.java:127) ~[springdoc-openapi-starter-webmvc-api-2.8.1.jar:2.8.1]
	at org.springdoc.webmvc.api.OpenApiWebMvcResource.openapiJson(OpenApiWebMvcResource.java:117) ~[springdoc-openapi-starter-webmvc-api-2.8.1.jar:2.8.1]
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:580) ~[na:na]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:257) ~[spring-web-6.2.1.jar:6.2.1]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:190) ~[spring-web-6.2.1.jar:6.2.1]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:118) ~[spring-webmvc-6.2.1.jar:6.2.1]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:986) ~[spring-webmvc-6.2.1.jar:6.2.1]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:891) ~[spring-webmvc-6.2.1.jar:6.2.1]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-6.2.1.jar:6.2.1]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1088) ~[spring-webmvc-6.2.1.jar:6.2.1]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:978) ~[spring-webmvc-6.2.1.jar:6.2.1]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1014) ~[spring-webmvc-6.2.1.jar:6.2.1]
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:903) ~[spring-webmvc-6.2.1.jar:6.2.1]
	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:564) ~[tomcat-embed-core-10.1.34.jar:6.0]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885) ~[spring-webmvc-6.2.1.jar:6.2.1]
	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) ~[tomcat-embed-core-10.1.34.jar:6.0]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:195) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) ~[tomcat-embed-websocket-10.1.34.jar:10.1.34]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-6.2.1.jar:6.2.1]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.2.1.jar:6.2.1]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-6.2.1.jar:6.2.1]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.2.1.jar:6.2.1]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-6.2.1.jar:6.2.1]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.2.1.jar:6.2.1]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:167) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:483) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:115) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:344) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:397) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:905) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1741) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1190) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63) ~[tomcat-embed-core-10.1.34.jar:10.1.34]
	at java.base/java.lang.Thread.run(Thread.java:1583) ~[na:na]

To Reproduce
Steps to reproduce the behavior:

• empty spring-boot-3.4.1 app (web, data-jpa, data-rest)
• springdoc-openapi-starter-webmvc-ui-2.8.1
• add some dummy entity along with a rest repository
• access /swagger-ui.html
• see stacktrace

Expected behavior

• no error (as with 2.7.x)

Screenshots
n/a

Additional context

• error disappears if reverting to springdoc.api-docs.version=openapi_3_0
• sample app will be referenced asap

thanks!

[bnasslahsen]

should be fixed by #2849