fix minor issues

Author: thegrumpylion

manage/manager.go

@@ -265,7 +265,7 @@ func (m *Manager) validateCodeChallenge(ti oauth2.TokenInfo, ver string) error {
 		return errors.ErrMissingCodeVerifier
 	}
 	if ver == "" {
-		return errors.New("missing code verifier")
+		return errors.ErrMissingCodeVerifier
 	}
 	ccm := ti.GetCodeChallengeMethod()
 	if ccm.String() == "" {

server/server.go

@@ -168,10 +168,8 @@ func (s *Server) ValidationAuthorizeRequest(r *http.Request) (*AuthorizeRequest,
 	if cc == "" && s.Config.ForcePKCE {
 		return nil, errors.ErrCodeChallengeRquired
 	}
-	if cc != "" {
-		if len(cc) < 43 || len(cc) > 128 {
-			return nil, errors.ErrInvalidCodeChallengeLen
-		}
+	if cc != "" && (len(cc) < 43 || len(cc) > 128) {
+		return nil, errors.ErrInvalidCodeChallengeLen
 	}
 
 	ccm := oauth2.CodeChallengeMethod(r.FormValue("code_challenge_method"))
@@ -313,10 +311,8 @@ func (s *Server) ValidationTokenRequest(r *http.Request) (oauth2.GrantType, *oau
 	}
 
 	codeVer := r.FormValue("code_verifier")
-	if s.Config.ForcePKCE {
-		if codeVer == "" {
-			return "", nil, errors.ErrInvalidRequest
-		}
+	if s.Config.ForcePKCE && codeVer == "" {
+		return "", nil, errors.ErrInvalidRequest
 	}
 
 	clientID, clientSecret, err := s.ClientInfoHandler(r)