feat(follow_redirect): Preserve extensions during redirection

tower-http/src/follow_redirect/mod.rs

@@ -6,8 +6,7 @@
 //! redirections.
 //!
 //! The middleware tries to clone the original [`Request`] when making a redirected request.
-//! However, since [`Extensions`][http::Extensions] are `!Clone`, any extensions set by outer
-//! middleware will be discarded. Also, the request body cannot always be cloned. When the
+//! However, the request body cannot always be cloned. When the
 //! original body is known to be empty by [`Body::size_hint`], the middleware uses `Default`
 //! implementation of the body type to create a new request body. If you know that the body can be
 //! cloned in some way, you can tell the middleware to clone it by configuring a [`policy`].
@@ -98,8 +97,8 @@ use self::policy::{Action, Attempt, Policy, Standard};
 use futures_util::future::Either;
 use http::{
     header::CONTENT_ENCODING, header::CONTENT_LENGTH, header::CONTENT_TYPE, header::LOCATION,
-    header::TRANSFER_ENCODING, HeaderMap, HeaderValue, Method, Request, Response, StatusCode, Uri,
-    Version,
+    header::TRANSFER_ENCODING, Extensions, HeaderMap, HeaderValue, Method, Request, Response,
+    StatusCode, Uri, Version,
 };
 use http_body::Body;
 use iri_string::types::{UriAbsoluteString, UriReferenceStr};
@@ -219,6 +218,7 @@ where
             uri: req.uri().clone(),
             version: req.version(),
             headers: req.headers().clone(),
+            extensions: req.extensions().clone(),
             body,
             future: Either::Left(service.call(req)),
             service,
@@ -242,6 +242,7 @@ pin_project! {
         uri: Uri,
         version: Version,
         headers: HeaderMap<HeaderValue>,
+        extensions: Extensions,
         body: BodyRepr<B>,
     }
 }
@@ -322,6 +323,7 @@ where
                 *req.method_mut() = this.method.clone();
                 *req.version_mut() = *this.version;
                 *req.headers_mut() = this.headers.clone();
+                *req.extensions_mut() = this.extensions.clone();
                 this.policy.on_request(&mut req);
                 this.future
                     .set(Either::Right(Oneshot::new(this.service.clone(), req)));