From 99de2a55d428c26f06dc7ef24dff8826b1e47860 Mon Sep 17 00:00:00 2001
From: Soheil Rahmat <soheilrt314@gmail.com>
Date: Fri, 14 Jul 2023 19:57:40 +0200
Subject: [PATCH] [BUG] Inconsistent HTTP status code on query mismatch

The logical behavour of a router should return http status code of 404 when a request fails to stisfy a route validation logics. Before this, mux was returning 405 http status code in some rare scenarios which is not a valid on its case.

For more info, See: https://github.com/gorilla/mux/issues/704
---
 mux_test.go | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 route.go    | 10 ++++++++++
 2 files changed, 57 insertions(+)

diff --git a/mux_test.go b/mux_test.go
index 2d8d2b3e..9b0f78c2 100644
--- a/mux_test.go
+++ b/mux_test.go
@@ -2068,6 +2068,53 @@ func TestNoMatchMethodErrorHandler(t *testing.T) {
 	}
 }
 
+func TestMultipleDefinitionOfSamePathWithDifferentMethods(t *testing.T) {
+	emptyHandler := func(w http.ResponseWriter, r *http.Request) {}
+
+	r := NewRouter()
+	r.HandleFunc("/api", emptyHandler).Methods("POST")
+	r.HandleFunc("/api", emptyHandler).Queries("time", "{time:[0-9]+}").Methods("GET")
+
+	t.Run("Post Method should be matched properly", func(t *testing.T) {
+		req, _ := http.NewRequest("POST", "http://localhost/api", nil)
+		match := new(RouteMatch)
+		matched := r.Match(req, match)
+		if !matched {
+			t.Error("Should have matched route for methods")
+		}
+		if match.MatchErr != nil {
+			t.Error("Should not have any matching error. Found:", match.MatchErr)
+		}
+	})
+
+	t.Run("Get Method with invalid query value should not match", func(t *testing.T) {
+		req, _ := http.NewRequest("GET", "http://localhost/api?time=-4", nil)
+		match := new(RouteMatch)
+		matched := r.Match(req, match)
+		if matched {
+			t.Error("Should not have matched route for methods")
+		}
+		if match.MatchErr != ErrNotFound {
+			t.Error("Should have ErrNotFound error. Found:", match.MatchErr)
+		}
+	})
+
+	t.Run("A mismach method of a valid path should return ErrMethodMismatch", func(t *testing.T) {
+		r := NewRouter()
+		r.HandleFunc("/api2", emptyHandler).Methods("POST")
+		req, _ := http.NewRequest("GET", "http://localhost/api2", nil)
+		match := new(RouteMatch)
+		matched := r.Match(req, match)
+		if matched {
+			t.Error("Should not have matched route for methods")
+		}
+		if match.MatchErr != ErrMethodMismatch {
+			t.Error("Should have ErrMethodMismatch error. Found:", match.MatchErr)
+		}
+	})
+
+}
+
 func TestErrMatchNotFound(t *testing.T) {
 	emptyHandler := func(w http.ResponseWriter, r *http.Request) {}
 
diff --git a/route.go b/route.go
index 750afe57..cfdede03 100644
--- a/route.go
+++ b/route.go
@@ -66,6 +66,16 @@ func (r *Route) Match(req *http.Request, match *RouteMatch) bool {
 
 			matchErr = nil
 			return false
+		} else {
+			// Multiple routes may share the same path but use different HTTP methods. For instance:
+			// Route 1: POST "/users/{id}".
+			// Route 2: GET "/users/{id}", parameters: "id": "[0-9]+".
+			//
+			// The router must handle these cases correctly. For a GET request to "/users/abc" with "id" as "-2",
+			// The router should return a "Not Found" error as no route fully matches this request.
+			if match.MatchErr == ErrMethodMismatch {
+				match.MatchErr = nil
+			}
 		}
 	}