Fix match_pattern() returning None for scope with resource of empty path (#1798)

* fix match_pattern function not returning pattern where scope has resource of path ""

* remove print in test

* make comparison on existing else if block

* add fix to changelog

CHANGES.md

@@ -4,6 +4,9 @@
 ### Fixed
 * Ensure `actix-http` dependency uses same `serde_urlencoded`.
 * Removed an occasional `unwrap` on `None` panic in `NormalizePathNormalization`.
+* Fix match_pattern() returning None for scope with resource of empty path. [#1798]
+
+[#1798]: https://github.com/actix/actix-web/pull/1798
 
 
 ## 3.3.0 - 2020-11-25

src/request.rs

@@ -675,4 +675,40 @@ mod tests {
         let res = call_service(&mut srv, req).await;
         assert_eq!(res.status(), StatusCode::OK);
     }
+
+    #[actix_rt::test]
+    async fn extract_path_pattern_complex() {
+        let mut srv = init_service(
+            App::new()
+                .service(web::scope("/user").service(web::scope("/{id}").service(
+                    web::resource("").to(move |req: HttpRequest| {
+                        assert_eq!(req.match_pattern(), Some("/user/{id}".to_owned()));
+
+                        HttpResponse::Ok().finish()
+                    }),
+                )))
+                .service(web::resource("/").to(move |req: HttpRequest| {
+                    assert_eq!(req.match_pattern(), Some("/".to_owned()));
+
+                    HttpResponse::Ok().finish()
+                }))
+                .default_service(web::to(move |req: HttpRequest| {
+                    assert!(req.match_pattern().is_none());
+                    HttpResponse::Ok().finish()
+                })),
+        )
+        .await;
+
+        let req = TestRequest::get().uri("/user/test").to_request();
+        let res = call_service(&mut srv, req).await;
+        assert_eq!(res.status(), StatusCode::OK);
+
+        let req = TestRequest::get().uri("/").to_request();
+        let res = call_service(&mut srv, req).await;
+        assert_eq!(res.status(), StatusCode::OK);
+
+        let req = TestRequest::get().uri("/not-exist").to_request();
+        let res = call_service(&mut srv, req).await;
+        assert_eq!(res.status(), StatusCode::OK);
+    }
 }

src/rmap.rs

@@ -86,7 +86,7 @@ impl ResourceMap {
                 if let Some(plen) = pattern.is_prefix_match(path) {
                     return rmap.has_resource(&path[plen..]);
                 }
-            } else if pattern.is_match(path) {
+            } else if pattern.is_match(path) || pattern.pattern() == "" && path == "/" {
                 return true;
             }
         }