Merge branch '6.2.x'

spring-webmvc/src/main/java/org/springframework/web/servlet/DispatcherServlet.java

@@ -49,6 +49,7 @@
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.support.PropertiesLoaderUtils;
 import org.springframework.core.log.LogFormatUtils;
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.MediaType;
 import org.springframework.http.server.RequestPath;
 import org.springframework.http.server.ServletServerHttpRequest;
@@ -1208,9 +1209,10 @@ protected HandlerAdapter getHandlerAdapter(Object handler) throws ServletExcepti
 
 		// Success and error responses may use different content types
 		request.removeAttribute(HandlerMapping.PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE);
-		// Reset the response body buffer if the response is not committed already,
-		// leaving the response headers in place.
+		// Reset the response content-type header and body buffer if the response is not committed already,
+		// leaving the other response headers in place.
 		try {
+			response.setHeader(HttpHeaders.CONTENT_TYPE, null);
 			response.resetBuffer();
 		}
 		catch (IllegalStateException illegalStateException) {

spring-webmvc/src/test/java/org/springframework/web/servlet/DispatcherServletTests.java

@@ -898,6 +898,23 @@ void shouldAttemptToResetResponseBufferIfCommitted() throws Exception {
 		assertThat(response.getHeader("Test-Header")).isEqualTo("spring");
 	}
 
+	@Test
+	void shouldResetContentTypeIfNotCommitted() throws Exception {
+		StaticWebApplicationContext context = new StaticWebApplicationContext();
+		context.setServletContext(getServletContext());
+		context.registerSingleton("/error", ErrorController.class);
+		DispatcherServlet servlet = new DispatcherServlet(context);
+		servlet.init(servletConfig);
+
+		MockHttpServletRequest request = new MockHttpServletRequest(getServletContext(), "GET", "/error");
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		assertThatThrownBy(() -> servlet.service(request, response)).isInstanceOf(ServletException.class)
+				.hasCauseInstanceOf(IllegalArgumentException.class);
+		assertThat(response.getContentAsByteArray()).isEmpty();
+		assertThat(response.getStatus()).isEqualTo(400);
+		assertThat(response.getHeaderNames()).doesNotContain(HttpHeaders.CONTENT_TYPE);
+	}
+
 
 	public static class ControllerFromParent implements Controller {
 
@@ -950,6 +967,7 @@ private static class ErrorController implements Controller {
 		public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {
 			response.setStatus(400);
 			response.setHeader("Test-Header", "spring");
+			response.addHeader("Content-Type", "application/json");
 			if (request.getAttribute("commit") != null) {
 				response.flushBuffer();
 			}