<!--- Please read this! Before opening a new issue, make sure to search for keywords in the issues filtered by the "regression" or "bug" label. For the Community Edition issue tracker: - https://gitlab.com/gitlab-org/gitlab-ce/issues?label_name%5B%5D=regression - https://gitlab.com/gitlab-org/gitlab-ce/issues?label_name%5B%5D=bug For the Enterprise Edition issue tracker: - https://gitlab.com/gitlab-org/gitlab-ee/issues?label_name%5B%5D=regression - https://gitlab.com/gitlab-org/gitlab-ee/issues?label_name%5B%5D=bug and verify the issue you're about to submit isn't a duplicate. ---> ### Summary Renaming the project name with illegal character (for example: start project name with `.`(dot or period), add `/` in name) leads to <strike>run `save changes` process for indefinite time</strike> disable **Save Changes** button and don't show any kind of warning message same as at time of new project creation, like below screenshot:  ### 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? <strike>`Save changes` process runs for indefinite time.</strike> **Save changes** button disabled. ### What is the expected *correct* behavior? After renaming with illegal character this warning should be shown and **Save changes** button should be reappeared.  ### Output of checks This happens on Gitlab.com