Merge branch '6.0.x'

framework-docs/modules/ROOT/pages/web/webmvc/filters.adoc

@@ -69,9 +69,10 @@ written to the response and computing an MD5 hash from it. The next time a clien
 it does the same, but it also compares the computed value against the `If-None-Match`
 request header and, if the two are equal, returns a 304 (NOT_MODIFIED).
 
-This strategy saves network bandwidth but not CPU, as the full response must be computed
-for each request. Other strategies at the controller level, described earlier, can avoid
-the computation. See xref:web/webmvc/mvc-caching.adoc[HTTP Caching].
+This strategy saves network bandwidth but not CPU, as the full response must be computed for each request.
+State-changing HTTP methods and other HTTP conditional request headers such as `If-Match` and `If-Unmodified-Since` are outside the scope of this filter.
+Other strategies at the controller level can avoid the computation and have a broader support for HTTP conditional requests.
+See xref:web/webmvc/mvc-caching.adoc[HTTP Caching].
 
 This filter has a `writeWeakETag` parameter that configures the filter to write weak ETags
 similar to the following: `W/"02a2d595e6ed9a0b24f027f2b63b134d6"` (as defined in

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

@@ -46,6 +46,10 @@ import org.springframework.web.util.WebUtils;
  * (e.g. a {@link org.springframework.web.servlet.View}) is still rendered.
  * As such, this filter only saves bandwidth, not server performance.
  *
+ * <p>State-changing HTTP methods and other HTTP conditional request headers such as
+ * {@code If-Match} and {@code If-Unmodified-Since} are outside the scope of this filter.
+ * Please consider using {@link ServletWebRequest#checkNotModified(String, long)} instead.
+ *
  * @author Arjen Poutsma
  * @author Rossen Stoyanchev
  * @author Brian Clozel