Negated produces works with no Accept header present

Issue: SPR-14299

Author: rstoyanchev

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/ProducesRequestCondition.java

@@ -26,6 +26,7 @@
 import javax.servlet.http.HttpServletRequest;
 
 import org.springframework.http.MediaType;
+import org.springframework.web.HttpMediaTypeException;
 import org.springframework.web.HttpMediaTypeNotAcceptableException;
 import org.springframework.web.accept.ContentNegotiationManager;
 import org.springframework.web.bind.annotation.RequestMapping;
@@ -193,7 +194,18 @@ public ProducesRequestCondition getMatchingCondition(HttpServletRequest request)
 				iterator.remove();
 			}
 		}
-		return (result.isEmpty()) ? null : new ProducesRequestCondition(result, this.contentNegotiationManager);
+		if (!result.isEmpty()) {
+			return new ProducesRequestCondition(result, this.contentNegotiationManager);
+		}
+		try {
+			if (getAcceptedMediaTypes(request).contains(MediaType.ALL)) {
+				return new ProducesRequestCondition();
+			}
+		}
+		catch (HttpMediaTypeException ex) {
+			// Ignore
+		}
+		return null;
 	}
 
 	/**

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/condition/ProducesRequestConditionTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,9 +24,14 @@
 import org.springframework.mock.web.test.MockHttpServletRequest;
 import org.springframework.web.servlet.mvc.condition.ProducesRequestCondition.ProduceMediaTypeExpression;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 /**
+ * Unit tests for {@link ProducesRequestCondition}.
  * @author Arjen Poutsma
  * @author Rossen Stoyanchev
  */
@@ -52,6 +57,15 @@ public void matchNegated() {
 		assertNull(condition.getMatchingCondition(request));
 	}
 
+	@Test
+	public void matchNegatedWithoutAcceptHeader() {
+		ProducesRequestCondition condition = new ProducesRequestCondition("!text/plain");
+		MockHttpServletRequest request = new MockHttpServletRequest();
+
+		assertNotNull(condition.getMatchingCondition(request));
+		assertEquals(Collections.emptySet(), condition.getProducibleMediaTypes());
+	}
+
 	@Test
 	public void getProducibleMediaTypes() {
 		ProducesRequestCondition condition = new ProducesRequestCondition("!application/xml");