fix: classify git failures on stderr, restrict migration failure detail (#39010)

Signed-off-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/api/v1/repo/migrate.go

@@ -8,7 +8,6 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
-	"strings"
 
 	"gitea.dev/models/db"
 	"gitea.dev/models/organization"
@@ -17,6 +16,7 @@ import (
 	repo_model "gitea.dev/models/repo"
 	user_model "gitea.dev/models/user"
 	"gitea.dev/modules/git"
+	"gitea.dev/modules/git/gitcmd"
 	"gitea.dev/modules/graceful"
 	"gitea.dev/modules/lfs"
 	"gitea.dev/modules/log"
@@ -245,11 +245,9 @@ func handleMigrateError(ctx *context.APIContext, repoOwner *user_model.User, err
 		ctx.APIError(http.StatusUnprocessableEntity, err.Error())
 	default:
 		err = util.SanitizeErrorCredentialURLs(err)
-		if strings.Contains(err.Error(), "Authentication failed") ||
-			strings.Contains(err.Error(), "Bad credentials") ||
-			strings.Contains(err.Error(), "could not read Username") {
+		if migrations.IsAuthenticationError(err) {
 			ctx.APIError(http.StatusUnprocessableEntity, fmt.Sprintf("Authentication failed: %v.", err))
-		} else if strings.Contains(err.Error(), "fatal:") {
+		} else if _, ok := gitcmd.ErrorAsStderr(err); ok {
 			ctx.APIError(http.StatusUnprocessableEntity, fmt.Sprintf("Migration failed: %v.", err))
 		} else {
 			ctx.APIErrorInternal(err)