Fix MockMvc + HttpPutFormContentFilter issue

Issue: SPR-15753

spring-test/src/test/java/org/springframework/test/web/servlet/samples/spr/FormContentTests.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2002-2017 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.test.web.servlet.samples.spr;
+
+import org.junit.Test;
+
+import org.springframework.http.MediaType;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.setup.MockMvcBuilders;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.filter.HttpPutFormContentFilter;
+
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.put;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+
+/**
+ * Test for issues related to form content.
+ * @author Rossen Stoyanchev
+ */
+public class FormContentTests {
+
+	@Test // SPR-15753
+	public void formContentIsNotDuplicated() throws Exception {
+
+		MockMvc mockMvc = MockMvcBuilders.standaloneSetup(new Spr15753Controller())
+				.addFilter(new HttpPutFormContentFilter())
+				.build();
+
+		mockMvc.perform(put("/").content("d1=a&d2=s").contentType(MediaType.APPLICATION_FORM_URLENCODED))
+				.andExpect(content().string("d1:a, d2:s."));
+
+	}
+
+
+	@RestController
+	public class Spr15753Controller {
+
+		@PutMapping
+		public String test(Data d) {
+			return String.format("d1:%s, d2:%s.", d.getD1(), d.getD2());
+		}
+	}
+
+	public class Data {
+
+		private String d1;
+
+		private String d2;
+
+		public Data() {
+		}
+
+		public String getD1() {
+			return d1;
+		}
+
+		public void setD1(String d1) {
+			this.d1 = d1;
+		}
+
+		public String getD2() {
+			return d2;
+		}
+
+		public void setD2(String d2) {
+			this.d2 = d2;
+		}
+	}
+}

spring-web/src/main/java/org/springframework/web/filter/HttpPutFormContentFilter.java

@@ -160,19 +160,20 @@ public class HttpPutFormContentFilter extends OncePerRequestFilter {
 		}
 
 		@Override
+		@Nullable
 		public String[] getParameterValues(String name) {
-			String[] queryStringValues = super.getParameterValues(name);
-			List<String> formValues = this.formParameters.get(name);
-			if (formValues == null) {
-				return queryStringValues;
+			String[] queryParam = (super.getQueryString() != null ? super.getParameterValues(name) : null);
+			List<String> formParam = this.formParameters.get(name);
+			if (formParam == null) {
+				return queryParam;
 			}
-			else if (queryStringValues == null) {
-				return formValues.toArray(new String[formValues.size()]);
+			else if (queryParam == null) {
+				return formParam.toArray(new String[formParam.size()]);
 			}
 			else {
-				List<String> result = new ArrayList<>(queryStringValues.length + formValues.size());
-				result.addAll(Arrays.asList(queryStringValues));
-				result.addAll(formValues);
+				List<String> result = new ArrayList<>(queryParam.length + formParam.size());
+				result.addAll(Arrays.asList(queryParam));
+				result.addAll(formParam);
 				return result.toArray(new String[result.size()]);
 			}
 		}

spring-web/src/test/java/org/springframework/web/filter/HttpPutFormContentFilterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -136,6 +136,7 @@ public class HttpPutFormContentFilterTests {
 
 	@Test
 	public void getParameterValues() throws Exception {
+		request.setQueryString("name=value1&name=value2");
 		request.addParameter("name", "value1");
 		request.addParameter("name", "value2");
 		request.setContent("name=value3&name=value4".getBytes("ISO-8859-1"));
@@ -149,6 +150,7 @@ public class HttpPutFormContentFilterTests {
 
 	@Test
 	public void getParameterValuesFromQueryString() throws Exception {
+		request.setQueryString("name=value1&name=value2");
 		request.addParameter("name", "value1");
 		request.addParameter("name", "value2");
 		request.setContent("anotherName=anotherValue".getBytes("ISO-8859-1"));
@@ -188,6 +190,7 @@ public class HttpPutFormContentFilterTests {
 
 	@Test
 	public void getParameterMap() throws Exception {
+		request.setQueryString("name=value1&name=value2");
 		request.addParameter("name", "value1");
 		request.addParameter("name", "value2");
 		request.setContent("name=value3&name4=value4".getBytes("ISO-8859-1"));