Addressed Review Comments and a Possible Bug

Author: maknahar

mux.go

@@ -13,6 +13,10 @@ import (
 	"strings"
 )
 
+var (
+	ErrMethodMismatch = errors.New("Method is Not Allowed")
+)
+
 // NewRouter returns a new router instance.
 func NewRouter() *Router {
 	return &Router{namedRoutes: make(map[string]*Route), KeepContext: false}
@@ -106,8 +110,8 @@ func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 		req = setCurrentRoute(req, match.Route)
 	}
 
-	if match.MethodMismatch {
-		handler = MethodNotAllowedHandler()
+	if handler == nil && match.MatchErr == ErrMethodMismatch {
+		handler = methodNotAllowedHandler()
 	}
 
 	if handler == nil {
@@ -351,9 +355,10 @@ type RouteMatch struct {
 	Handler http.Handler
 	Vars    map[string]string
 
-	// MethodMismatch flag is set to true if a route is matched but there
-	// is a mismatch in the request method and route method
-	MethodMismatch bool
+	// MatchErr is set to appropriate matching error
+	// It is set to ErrMethodMismatch if there is a mismatch in
+	// the request method and route method
+	MatchErr error
 }
 
 type contextKey int
@@ -556,11 +561,11 @@ func matchMapWithRegex(toCheck map[string]*regexp.Regexp, toMatch map[string][]s
 	return true
 }
 
-// MethodNotAllowed replies to the request with an HTTP status code 405.
-func MethodNotAllowed(w http.ResponseWriter, r *http.Request) {
+// methodNotAllowed replies to the request with an HTTP status code 405.
+func methodNotAllowed(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusMethodNotAllowed)
 }
 
-// MethodNotAllowedHandler returns a simple request handler
+// methodNotAllowedHandler returns a simple request handler
 // that replies to each request with a status code 405.
-func MethodNotAllowedHandler() http.Handler { return http.HandlerFunc(MethodNotAllowed) }
+func methodNotAllowedHandler() http.Handler { return http.HandlerFunc(methodNotAllowed) }

mux_test.go

@@ -1887,6 +1887,10 @@ func TestNoMatchMethodErrors(t *testing.T) {
 		t.Error("Should not have matched route for methods")
 	}
 
+	if match.MatchErr != ErrMethodMismatch {
+		t.Error("Should get ErrMethodMismatch error")
+	}
+
 	resp := NewRecorder()
 	r.ServeHTTP(resp, req)
 	if resp.Code != 405 {

route.go

@@ -57,14 +57,14 @@ func (r *Route) Match(req *http.Request, match *RouteMatch) bool {
 	for _, m := range r.matchers {
 		if matched := m.Match(req, match); !matched {
 			if _, ok := m.(methodMatcher); ok {
-				match.MethodMismatch = true
+				match.MatchErr = ErrMethodMismatch
 				continue
 			}
 			return false
 		}
 	}
 
-	if match.MethodMismatch {
+	if match.MatchErr != nil {
 		return false
 	}