NPE in RequestBodyService#buildRequestBody when using javadoc

[zman0900]

Describe the bug
Using springdoc 1.6.13 or 1.6.14, with the javadoc plugin and a controller method that has a parameter annotated with @RequestBody and javadoc for that parameter, accessing Swagger UI shows 500 error and log shows NullPointerException.

The stack trace

java.lang.NullPointerException: Cannot invoke "io.swagger.v3.oas.models.parameters.RequestBody.setDescription(String)" because the return value of "org.springdoc.core.RequestBodyInfo.getRequestBody()" is null
      at org.springdoc.core.RequestBodyService.buildRequestBody(RequestBodyService.java:290)
      at org.springdoc.core.RequestBodyService.calculateRequestBodyInfo(RequestBodyService.java:251)
      at org.springdoc.core.AbstractRequestService.build(AbstractRequestService.java:329)
      at org.springdoc.api.AbstractOpenApiResource.calculatePath(AbstractOpenApiResource.java:503)
      at org.springdoc.api.AbstractOpenApiResource.calculatePath(AbstractOpenApiResource.java:665)
      at org.springdoc.webmvc.api.OpenApiResource.lambda$calculatePath$11(OpenApiResource.java:234)
      at java.base/java.util.Optional.ifPresent(Optional.java:178)
      at org.springdoc.webmvc.api.OpenApiResource.calculatePath(OpenApiResource.java:215)
      at org.springdoc.webmvc.api.OpenApiResource.lambda$getPaths$2(OpenApiResource.java:185)
      at java.base/java.util.Optional.ifPresent(Optional.java:178)
      at org.springdoc.webmvc.api.OpenApiResource.getPaths(OpenApiResource.java:164)
      at org.springdoc.api.AbstractOpenApiResource.getOpenApi(AbstractOpenApiResource.java:364)
      at org.springdoc.webmvc.api.OpenApiResource.openapiJson(OpenApiResource.java:139)
      at org.springdoc.webmvc.api.OpenApiWebMvcResource.openapiJson(OpenApiWebMvcResource.java:116)
      at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
      at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.base/java.lang.reflect.Method.invoke(Method.java:568)
      at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
      at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150)
      at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117)
      at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
      at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)
      at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
      at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1071)
      at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:964)
      at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
      at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:670)
      at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:779)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
      at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
      at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
      at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
      at org.springframework.cloud.sleuth.instrument.web.servlet.TracingFilter.doFilter(TracingFilter.java:68)
      at org.springframework.cloud.sleuth.autoconfig.instrument.web.TraceWebServletConfiguration$LazyTracingFilter.doFilter(TraceWebServletConfiguration.java:131)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
      at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:177)
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
      at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
      at ch.qos.logback.access.tomcat.LogbackValve.invoke(LogbackValve.java:256)
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
      at org.springframework.cloud.sleuth.instrument.web.tomcat.TraceValve.invoke(TraceValve.java:103)
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360)
      at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)
      at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
      at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:891)
      at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1784)
      at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
      at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
      at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
      at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
      at java.base/java.lang.Thread.run(Thread.java:833)

This seems to happen because org.springdoc.core.RequestBodyService#buildRequestBody is called with non-null requestBody parameter, but with requestBodyInfo parameter containing null for its requestBody field. The only apparent caller of that buildRequestBody method is calculateRequestBodyInfo in the same class, and it does not set requestBody in requestBodyInfo until after making the call.

To Reproduce
Steps to reproduce the behavior:

• What version of spring-boot you are using? 2.7.9
• What modules and versions of springdoc-openapi are you using? 1.6.14, with the common, ui, and javadoc modules

@RestController
class Sample {
  /**
   * Sample method.
   * 
   * @param value doc for the request body
   */
  public void something(@RequestBody final String value) {
    // whatever
  }
}

Expected behavior
Expecting Swagger UI to function as it does when using springdoc 1.6.12.

[uc4w6c]

@zman0900
I didn't have this problem locally. (see: https://github.com/uc4w6c/springdoc-javadoc)
Would it be possible for you to provide a minimal repository to reproduce?

[bnasslahsen]

@zman0900,

Not reproducible.

[zman0900]

@bnasslahsen please re-open this, it can be reproduced.

Here is a small demo project: https://github.com/zman0900/springdoc-2089-demo

Important part is in the DemoController#update method. When swagger's @RequestBody annotation is used on a parameter without setting the description field, the error in this issue happens. It works if I remove swagger's @RequestBody entirely, but then the swagger UI doesn't document the expected schema. It also works if I add the description field, but then the string from the javadoc must be duplicated. Finally, it works if I downgrade to 1.6.12.

[bnasslahsen]

@zman0900,

A PR provided by @uc4w6c is now merged for this issue!

[zman0900]

Thanks. Any plan to release another 1.6.x version for those of us still stuck on Spring Boot 2, or will this only be in next 2.x release?

[bnasslahsen]

both will be released by the end of this week

[zman0900]

Awesome, thanks