Renaming project name with illegal characters

Summary

Renaming the project name with illegal character (for example: start project name with .(dot or period), add / in name) leads to run save changes process for indefinite time and don't show any kind of warning message same as at time of new project creation.

Steps to reproduce

• Go to Settings -> General
• Rename project with illegal character(s) (for example: start name with .(dot or period)).
• Click save changes

Example Project

We can reproduce this bug on any project.

What is the current bug behavior?

Save changes process runs for indefinite time.

What is the expected correct behavior?

After renaming with illegal character this warning should be shown

Output of checks

This happens on Gitlab.com