Remove final declaration from getMessageSource() and getLocale() methods

Includes checking the Servlet 3.0+ ServletRequest.getServletContext() method in the request-only constructors, being able to fall back to the root WebApplicationContext.

See gh-32926

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

@@ -132,29 +132,29 @@ public class RequestContext {
 	 * Create a new RequestContext for the given request, using the request attributes for Errors retrieval.
 	 * <p>This only works with InternalResourceViews, as Errors instances are part of the model and not
 	 * normally exposed as request attributes. It will typically be used within JSPs or custom tags.
-	 * <p><b>Will only work within a DispatcherServlet request.</b>
-	 * Pass in a ServletContext to be able to fall back to the root WebApplicationContext.
+	 * <p>As of 6.2, this will work within a DispatcherServlet request as well as with the root
+	 * WebApplicationContext (outside a DispatcherServlet).
 	 * @param request current HTTP request
 	 * @see org.springframework.web.servlet.DispatcherServlet
 	 * @see #RequestContext(jakarta.servlet.http.HttpServletRequest, jakarta.servlet.ServletContext)
 	 */
 	public RequestContext(HttpServletRequest request) {
-		this(request, null, null, null);
+		this(request, null, request.getServletContext(), null);
 	}
 
 	/**
 	 * Create a new RequestContext for the given request, using the request attributes for Errors retrieval.
 	 * <p>This only works with InternalResourceViews, as Errors instances are part of the model and not
 	 * normally exposed as request attributes. It will typically be used within JSPs or custom tags.
-	 * <p><b>Will only work within a DispatcherServlet request.</b>
-	 * Pass in a ServletContext to be able to fall back to the root WebApplicationContext.
+	 * <p>As of 6.2, this will work within a DispatcherServlet request as well as with the root
+	 * WebApplicationContext (outside a DispatcherServlet).
 	 * @param request current HTTP request
 	 * @param response current HTTP response
 	 * @see org.springframework.web.servlet.DispatcherServlet
 	 * @see #RequestContext(jakarta.servlet.http.HttpServletRequest, jakarta.servlet.http.HttpServletResponse, jakarta.servlet.ServletContext, Map)
 	 */
 	public RequestContext(HttpServletRequest request, HttpServletResponse response) {
-		this(request, response, null, null);
+		this(request, response, request.getServletContext(), null);
 	}
 
 	/**
@@ -176,8 +176,8 @@ public class RequestContext {
 	/**
 	 * Create a new RequestContext for the given request, using the given model attributes for Errors retrieval.
 	 * <p>This works with all View implementations. It will typically be used by View implementations.
-	 * <p><b>Will only work within a DispatcherServlet request.</b>
-	 * Pass in a ServletContext to be able to fall back to the root WebApplicationContext.
+	 * <p>As of 6.2, this will work within a DispatcherServlet request as well as with the root
+	 * WebApplicationContext (outside a DispatcherServlet).
 	 * @param request current HTTP request
 	 * @param model the model attributes for the current view (can be {@code null},
 	 * using the request attributes for Errors retrieval)
@@ -185,7 +185,7 @@ public class RequestContext {
 	 * @see #RequestContext(jakarta.servlet.http.HttpServletRequest, jakarta.servlet.http.HttpServletResponse, jakarta.servlet.ServletContext, Map)
 	 */
 	public RequestContext(HttpServletRequest request, @Nullable Map<String, Object> model) {
-		this(request, null, null, model);
+		this(request, null, request.getServletContext(), model);
 	}
 
 	/**
@@ -281,13 +281,6 @@ public class RequestContext {
 		return this.webApplicationContext;
 	}
 
-	/**
-	 * Return the current WebApplicationContext as MessageSource.
-	 */
-	public final MessageSource getMessageSource() {
-		return this.webApplicationContext;
-	}
-
 	/**
 	 * Return the model Map that this RequestContext encapsulates, if any.
 	 * @return the populated model Map, or {@code null} if none available
@@ -297,13 +290,22 @@ public class RequestContext {
 		return this.model;
 	}
 
+	/**
+	 * Return the MessageSource to use (typically the current WebApplicationContext).
+	 * <p>Note: As of 6.2, this method is non-final and therefore overridable.
+	 */
+	public MessageSource getMessageSource() {
+		return this.webApplicationContext;
+	}
+
 	/**
 	 * Return the current Locale (falling back to the request locale; never {@code null}).
 	 * <p>Typically coming from a DispatcherServlet's {@link LocaleResolver}.
 	 * Also includes a fallback check for JSTL's Locale attribute.
+	 * <p>Note: As of 6.2, this method is non-final and therefore overridable.
 	 * @see RequestContextUtils#getLocale
 	 */
-	public final Locale getLocale() {
+	public Locale getLocale() {
 		return (this.locale != null ? this.locale : getFallbackLocale());
 	}