chore: preserve extra token properties during refresh

util/oauth/tokensource.go

@@ -46,12 +46,16 @@ func (ts *TokenSource) Token() (*oauth2.Token, error) {
 	}
 
 	if token.AccessToken == "" {
-		err = errors.New("token refresh failed to obtain access token")
-	} else {
-		err = ts.mergeToken(token)
+		return nil, errors.New("token refresh failed to obtain access token")
 	}
 
-	return ts.token, err
+	if token.RefreshToken == "" {
+		token.RefreshToken = ts.token.RefreshToken
+	}
+
+	ts.token = token
+
+	return ts.token, nil
 }
 
 // mergeToken updates a token while preventing wiping the refresh token

util/oauth/tokensource_test.go

@@ -2,30 +2,36 @@ package oauth
 
 import (
 	"testing"
+	"time"
 
+	"github.com/stretchr/testify/require"
 	"golang.org/x/oauth2"
 )
 
+type tkr struct{}
+
+func (tkr *tkr) RefreshToken(_ *oauth2.Token) (*oauth2.Token, error) {
+	return (&oauth2.Token{
+		AccessToken: "new",
+	}).WithExtra(map[string]any{
+		"foo": "bar",
+	}), nil
+}
+
 func TestMerge(t *testing.T) {
 	ts := &TokenSource{
 		token: &oauth2.Token{
 			AccessToken:  "access",
 			RefreshToken: "refresh",
+			Expiry:       time.Now(),
 		},
+		refresher: new(tkr),
 	}
 
-	r := &oauth2.Token{
-		AccessToken: "new",
-	}
+	r, err := ts.Token()
+	require.NoError(t, err)
 
-	if err := ts.mergeToken(r); err != nil {
-		t.Error(err)
-	}
-
-	if ts.token.AccessToken != "new" {
-		t.Error("unexpected access token", ts.token)
-	}
-	if ts.token.RefreshToken != "refresh" {
-		t.Error("unexpected refresh token", ts.token)
-	}
+	require.Equal(t, "new", r.AccessToken, "unexpected access token")
+	require.Equal(t, "refresh", r.RefreshToken, "unexpected refresh token")
+	require.Equal(t, "bar", r.Extra("foo"))
 }