add user rename endpoint to admin api (#22789)

this is a simple endpoint that adds the ability to rename users to the
admin API.

Note: this is not in a mergeable state. It would be better if this was
handled by a PATCH/POST to the /api/v1/admin/users/{username} endpoint
and the username is modified.

---------

Co-authored-by: Jason Song <i@wolfogre.com>

2 files changed, 57 insertions, 0 deletions

diff --git a/services/user/rename.go b/services/user/rename.go
new file mode 100644
index 0000000000..af195d7d76
--- /dev/null
+++ b/services/user/rename.go
@@ -0,0 +1,41 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package user
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/services/agit"
+	container_service "code.gitea.io/gitea/services/packages/container"
+)
+
+func renameUser(ctx context.Context, u *user_model.User, newUserName string) error {
+	if u.IsOrganization() {
+		return fmt.Errorf("cannot rename organization")
+	}
+
+	if err := user_model.ChangeUserName(ctx, u, newUserName); err != nil {
+		return err
+	}
+
+	if err := agit.UserNameChanged(ctx, u, newUserName); err != nil {
+		return err
+	}
+	if err := container_service.UpdateRepositoryNames(ctx, u, newUserName); err != nil {
+		return err
+	}
+
+	u.Name = newUserName
+	u.LowerName = strings.ToLower(newUserName)
+	if err := user_model.UpdateUser(ctx, u, false); err != nil {
+		return err
+	}
+
+	log.Trace("User name changed: %s -> %s", u.Name, newUserName)
+	return nil
+}
diff --git a/services/user/user.go b/services/user/user.go
index f0b8fe1c31..d52a2f404b 100644
--- a/services/user/user.go
+++ b/services/user/user.go
@@ -27,6 +27,22 @@ import (
 	"code.gitea.io/gitea/services/packages"
 )
 
+// RenameUser renames a user
+func RenameUser(ctx context.Context, u *user_model.User, newUserName string) error {
+	ctx, committer, err := db.TxContext(ctx)
+	if err != nil {
+		return err
+	}
+	defer committer.Close()
+	if err := renameUser(ctx, u, newUserName); err != nil {
+		return err
+	}
+	if err := committer.Commit(); err != nil {
+		return err
+	}
+	return err
+}
+
 // DeleteUser completely and permanently deletes everything of a user,
 // but issues/comments/pulls will be kept and shown as someone has been deleted,
 // unless the user is younger than USER_DELETE_WITH_COMMENTS_MAX_DAYS.