FlashMapManager throws StringIndexOutOfBoundsException for empty target URL path

[pbluong]

Hello,

My project is currently using Spring MVC version 5.0.8.

Incidentally, I found a technical error relating to the library.

It is about the method decodeAndNormalizePath of the AbstractFlashMapManager class. If you look at the implementation, you can easily see that it is wrong. An empty path will pass the null check but fail to get the first character.

private String decodeAndNormalizePath(@Nullable String path, HttpServletRequest request) {
/* 231 */       if(path != null) {
/* 232 */          path = this.getUrlPathHelper().decodeRequestString(request, path);
/* 233 */          if(path.charAt(0) != 47) {
/* 234 */             String requestUri = this.getUrlPathHelper().getRequestUri(request);
/* 235 */             path = requestUri.substring(0, requestUri.lastIndexOf(47) + 1) + path;
/* 236 */             path = StringUtils.cleanPath(path);
/*     */          }      }
/*     */ 
/* 239 */       return path;
/*     */    }

org.apache.catalina.core.ApplicationDispatcher.invoke Servlet.service() for servlet [tnjs-servlet] threw exception
 java.lang.StringIndexOutOfBoundsException: String index out of range: 0
	at java.base/java.lang.StringLatin1.charAt(StringLatin1.java:44)
	at java.base/java.lang.String.charAt(String.java:704)
	at org.springframework.web.servlet.support.AbstractFlashMapManager.decodeAndNormalizePath(AbstractFlashMapManager.java:233)
	at org.springframework.web.servlet.support.AbstractFlashMapManager.saveOutputFlashMap(AbstractFlashMapManager.java:204)
	at org.springframework.web.servlet.support.RequestContextUtils.saveOutputFlashMap(RequestContextUtils.java:281)
	at org.springframework.web.servlet.view.RedirectView.renderMergedOutputModel(RedirectView.java:311)
	at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:314)
	at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1325)
	at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1069)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1008)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:866)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

[sbrannen]

Thanks for raising the issue. We'll look into it.