fix github migration error when using multiple tokens (#34144)

Git authorization was not taking into account multiple token feature,
leading to auth failures

Closes: https://github.com/go-gitea/gitea/issues/34141

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
(cherry picked from commit 8a6df00c532becd4d10efb70827ccf80b2bf74e2)

services/migrations/github.go

@@ -140,7 +140,7 @@ func (g *GithubDownloaderV3) LogString() string {
 func (g *GithubDownloaderV3) addClient(client *http.Client, baseURL string) {
 	githubClient := github.NewClient(client)
 	if baseURL != "https://github.com" {
-		githubClient, _ = github.NewClient(client).WithEnterpriseURLs(baseURL, baseURL)
+		githubClient, _ = githubClient.WithEnterpriseURLs(baseURL, baseURL)
 	}
 	g.clients = append(g.clients, githubClient)
 	g.rates = append(g.rates, nil)
@@ -885,3 +885,18 @@ func (g *GithubDownloaderV3) GetReviews(reviewable base.Reviewable) ([]*base.Rev
 	}
 	return allReviews, nil
 }
+
+// FormatCloneURL add authentication into remote URLs
+func (g *GithubDownloaderV3) FormatCloneURL(opts MigrateOptions, remoteAddr string) (string, error) {
+	u, err := url.Parse(remoteAddr)
+	if err != nil {
+		return "", err
+	}
+	if len(opts.AuthToken) > 0 {
+		// "multiple tokens" are used to benefit more "API rate limit quota"
+		// git clone doesn't count for rate limits, so only use the first token.
+		// source: https://github.com/orgs/community/discussions/44515
+		u.User = url.UserPassword("oauth2", strings.Split(opts.AuthToken, ",")[0])
+	}
+	return u.String(), nil
+}

services/migrations/github_test.go

@@ -433,3 +433,36 @@ func TestGitHubDownloadRepo(t *testing.T) {
 		},
 	}, reviews)
 }
+
+func TestGithubMultiToken(t *testing.T) {
+	testCases := []struct {
+		desc             string
+		token            string
+		expectedCloneURL string
+	}{
+		{
+			desc:             "Single Token",
+			token:            "single_token",
+			expectedCloneURL: "https://oauth2:single_token@github.com",
+		},
+		{
+			desc:             "Multi Token",
+			token:            "token1,token2",
+			expectedCloneURL: "https://oauth2:token1@github.com",
+		},
+	}
+	factory := GithubDownloaderV3Factory{}
+
+	for _, tC := range testCases {
+		t.Run(tC.desc, func(t *testing.T) {
+			opts := base.MigrateOptions{CloneAddr: "https://github.com/go-gitea/gitea", AuthToken: tC.token}
+			client, err := factory.New(t.Context(), opts)
+			require.NoError(t, err)
+
+			cloneURL, err := client.FormatCloneURL(opts, "https://github.com")
+			require.NoError(t, err)
+
+			assert.Equal(t, tC.expectedCloneURL, cloneURL)
+		})
+	}
+}