http-client: Avoid a space leak when storing original requests

`Network.HTTP.Client.Response.getResponse` stores the original request
inside a `Response`, but attempts to override its request body with an
empty one. This record update was lazy, and a reference to the
original request body would persist, causing a space leak.

Force the response to WHNF, and use bang patterns to force the Request
and ultimately its body to WHNF too.

http-client/ChangeLog.md

@@ -1,5 +1,9 @@
 # Changelog for http-client
 
+## Unreleased
+
+* Fix a space leak when storing original requests inside responses
+
 ## 0.7.17
 
 * Add `managerSetMaxHeaderLength` to `Client` to change `ManagerSettings` `MaxHeaderLength`.

http-client/Network/HTTP/Client/Response.hs

@@ -154,7 +154,7 @@ getResponse mhl timeout' req@(Request {..}) mconn cont = do
                     then makeGzipReader body1
                     else return body1
 
-    return Response
+    return $! Response
         { responseStatus = s
         , responseVersion = version
         , responseHeaders = hs

http-client/Network/HTTP/Client/Types.hs

@@ -537,7 +537,7 @@ data Request = Request
     -- are honoured.
     --
     -- Since 0.1.0
-    , requestBody :: RequestBody
+    , requestBody :: !RequestBody
     -- ^ Request body to be sent to the server.
     --
     -- Since 0.1.0
@@ -714,7 +714,7 @@ data Response body = Response
     -- be impossible.
     --
     -- Since 0.1.0
-    , responseOriginalRequest :: Request
+    , responseOriginalRequest :: !Request
     -- ^ Holds original @Request@ related to this @Response@ (with an empty body).
     -- This field is intentionally not exported directly, but made available
     -- via @getOriginalRequest@ instead.