Use original query string of forwarded request

Prior to this commit, the AbstractFlashMapManager has used the
originating URI but the query string of the forwarded request. That
resulted to FlashMap not being matched even when both originating
URI and query string matched the FlashMap attributes. The originating
query string is now used to match the forwarded request.

Issue: SPR-15505

Author: svorcmar

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

@@ -33,7 +33,6 @@
 import org.springframework.util.StringUtils;
 import org.springframework.web.servlet.FlashMap;
 import org.springframework.web.servlet.FlashMapManager;
-import org.springframework.web.util.UriComponents;
 import org.springframework.web.util.UrlPathHelper;
 
 
@@ -173,8 +172,7 @@ protected boolean isFlashMapForRequest(FlashMap flashMap, HttpServletRequest req
 				return false;
 			}
 		}
-		UriComponents uriComponents = ServletUriComponentsBuilder.fromRequest(request).build();
-		MultiValueMap<String, String> actualParams = uriComponents.getQueryParams();
+		MultiValueMap<String, String> actualParams = getOriginatingRequestParams(request);
 		MultiValueMap<String, String> expectedParams = flashMap.getTargetRequestParams();
 		for (String expectedName : expectedParams.keySet()) {
 			List<String> actualValues = actualParams.get(expectedName);
@@ -190,6 +188,11 @@ protected boolean isFlashMapForRequest(FlashMap flashMap, HttpServletRequest req
 		return true;
 	}
 
+	private MultiValueMap<String, String> getOriginatingRequestParams(HttpServletRequest request) {
+		String query = getUrlPathHelper().getOriginatingQueryString(request);
+		return ServletUriComponentsBuilder.fromPath("/").query(query).build().getQueryParams();
+	}
+
 	@Override
 	public final void saveOutputFlashMap(FlashMap flashMap, HttpServletRequest request, HttpServletResponse response) {
 		if (CollectionUtils.isEmpty(flashMap)) {

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

@@ -21,6 +21,7 @@
 import java.net.URLEncoder;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
 
@@ -318,6 +319,25 @@ public void flashAttributesWithQueryParamsWithSpace() throws Exception {
 		assertEquals("value", flashMap.get("key"));
 	}
 
+	@Test // SPR-15505
+	public void retrieveAndUpdateMatchByOriginatingPathAndQueryString() {
+		FlashMap flashMap = new FlashMap();
+		flashMap.put("key", "value");
+		flashMap.setTargetRequestPath("/accounts");
+		flashMap.addTargetRequestParam("a", "b");
+
+		this.flashMapManager.setFlashMaps(Collections.singletonList(flashMap));
+
+		this.request.setAttribute(WebUtils.FORWARD_REQUEST_URI_ATTRIBUTE, "/accounts");
+		this.request.setAttribute(WebUtils.FORWARD_QUERY_STRING_ATTRIBUTE, "a=b");
+		this.request.setRequestURI("/mvc/accounts");
+		this.request.setQueryString("x=y");
+		FlashMap inputFlashMap = this.flashMapManager.retrieveAndUpdate(this.request, this.response);
+
+		assertEquals(flashMap, inputFlashMap);
+		assertEquals("Input FlashMap should have been removed", 0, this.flashMapManager.getFlashMaps().size());
+	}
+
 
 	private static class TestFlashMapManager extends AbstractFlashMapManager {