Use stream or writer for top level exception to response (#3970)

core/impl/src/main/java/cloud/piranha/core/impl/DefaultServletRequestDispatcher.java

@@ -27,21 +27,6 @@
  */
 package cloud.piranha.core.impl;
 
-import cloud.piranha.core.api.CurrentRequestHolder;
-import static cloud.piranha.core.api.CurrentRequestHolder.CURRENT_REQUEST_ATTRIBUTE;
-import cloud.piranha.core.api.FilterEnvironment;
-import cloud.piranha.core.api.ServletEnvironment;
-import cloud.piranha.core.api.WebApplicationRequest;
-import static cloud.piranha.core.impl.DefaultWebApplicationRequest.unwrap;
-import static jakarta.servlet.AsyncContext.ASYNC_CONTEXT_PATH;
-import static jakarta.servlet.AsyncContext.ASYNC_PATH_INFO;
-import static jakarta.servlet.AsyncContext.ASYNC_QUERY_STRING;
-import static jakarta.servlet.AsyncContext.ASYNC_REQUEST_URI;
-import static jakarta.servlet.AsyncContext.ASYNC_SERVLET_PATH;
-import static jakarta.servlet.DispatcherType.ASYNC;
-import static jakarta.servlet.DispatcherType.ERROR;
-import static jakarta.servlet.DispatcherType.FORWARD;
-import static jakarta.servlet.DispatcherType.INCLUDE;
 import jakarta.servlet.RequestDispatcher;
 import jakarta.servlet.ServletException;
 import jakarta.servlet.ServletRequest;
@@ -51,10 +36,10 @@
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletRequestWrapper;
 import jakarta.servlet.http.HttpServletResponse;
-import static jakarta.servlet.http.HttpServletResponse.SC_INTERNAL_SERVER_ERROR;
-import static jakarta.servlet.http.HttpServletResponse.SC_NOT_FOUND;
 import jakarta.servlet.http.HttpSession;
+
 import java.io.IOException;
+import java.io.PrintStream;
 import java.net.URLDecoder;
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
@@ -63,6 +48,25 @@
 import java.util.Map;
 import java.util.function.Predicate;
 
+import cloud.piranha.core.api.CurrentRequestHolder;
+import cloud.piranha.core.api.FilterEnvironment;
+import cloud.piranha.core.api.ServletEnvironment;
+import cloud.piranha.core.api.WebApplicationRequest;
+
+import static cloud.piranha.core.api.CurrentRequestHolder.CURRENT_REQUEST_ATTRIBUTE;
+import static cloud.piranha.core.impl.DefaultWebApplicationRequest.unwrap;
+import static jakarta.servlet.AsyncContext.ASYNC_CONTEXT_PATH;
+import static jakarta.servlet.AsyncContext.ASYNC_PATH_INFO;
+import static jakarta.servlet.AsyncContext.ASYNC_QUERY_STRING;
+import static jakarta.servlet.AsyncContext.ASYNC_REQUEST_URI;
+import static jakarta.servlet.AsyncContext.ASYNC_SERVLET_PATH;
+import static jakarta.servlet.DispatcherType.ASYNC;
+import static jakarta.servlet.DispatcherType.ERROR;
+import static jakarta.servlet.DispatcherType.FORWARD;
+import static jakarta.servlet.DispatcherType.INCLUDE;
+import static jakarta.servlet.http.HttpServletResponse.SC_INTERNAL_SERVER_ERROR;
+import static jakarta.servlet.http.HttpServletResponse.SC_NOT_FOUND;
+
 /**
  * The default ServletRequestDispatcher.
  *
@@ -170,10 +174,10 @@ public void request(DefaultWebApplicationRequest webappRequest, DefaultWebApplic
  }
 
  /*
- * REFACTOR - We used a response header to signal that we are not 
+ * REFACTOR - We used a response header to signal that we are not
  * listening to add/setHeader. In the block below we remove the header
  * and reset the buffer as we need the code below do its work. However
- * we really need to refactor this and move the code below to the 
+ * we really need to refactor this and move the code below to the
  * DefaultWebApplicationResponse, because it should be handled in the
  * sendError call.
  */
@@ -199,7 +203,11 @@ public void request(DefaultWebApplicationRequest webappRequest, DefaultWebApplic
  rethrow(e);
  }
  } else if (exception != null) {
- exception.printStackTrace(webappResponse.getWriter());
+ if (webappResponse.gotWriter) {
+ exception.printStackTrace(webappResponse.getWriter());
+ } else {
+ exception.printStackTrace(new PrintStream(webappResponse.getOutputStream()));
+ }
  webappResponse.flushBuffer();
  rethrow(exception);
  } else if (webappRequest.getAttribute(ERROR_MESSAGE) != null) {
@@ -279,7 +287,7 @@ public void include(ServletRequest servletRequest, ServletResponse servletRespon
  request.setDispatcherType(INCLUDE);
  request.setServletPath(path == null ? "/" + servletEnvironment.getServletName() : getServletPath(path));
  request.setPathInfo(null);
- 
+
  if (path != null) {
  request.setQueryString(getQueryString(path));
  }