<!--- Please read this! Before opening a new issue, make sure to search for keywords in the issues filtered by the "regression" or "type::bug" label: - https://gitlab.com/gitlab-org/gitlab/issues?label_name%5B%5D=regression - https://gitlab.com/gitlab-org/gitlab/issues?label_name%5B%5D=type::bug and verify the issue you're about to submit isn't a duplicate. ---> ### Summary <!-- Summarize the bug encountered concisely. --> When [creating an LDAP group link](https://docs.gitlab.com/ee/user/group/access_and_permissions.html#manage-group-memberships-with-ldap), the LDAP Access dropdown used to have a default value of `Guest`. In more recent versions of GitLab (tested with 17.4.1 and above), the dropdown does not have a default value. If you click on `Add Synchronization` without selecting a role, you will receive a 500 error: ``` "exception.class": "ActiveRecord::NotNullViolation", "exception.message": "PG::NotNullViolation: ERROR: null value in column \"group_access\" of relation \"ldap_group_links\" violates not-null constraint\nDETAIL: Failing row contains (7, gitlab-group-1, null, 2, 2024-12-10 10:27:03.131423, 2024-12-10 10:27:03.131423, ldapmain, null, null).\n", 2 files ``` This should be better handled in the UI instead of throwing an exception. ### Steps to reproduce <!-- Describe how one can reproduce the issue - this is very important. Please use an ordered list. --> - [Configure LDAP group synchronization](https://docs.gitlab.com/ee/administration/auth/ldap/ldap_synchronization.html#group-sync) - Click on `Add Synchronization` under a Group's **Settings > LDAP Synchronzation** page without setting a value for LDAP Access - You will receive a 500 error and a `ActiveRecord::NotNullViolation` exception will be present in the logs. <!-- ### Example Project If possible, please create an example project here on GitLab.com that exhibits the problematic behavior, and link to it here in the bug report. If you are using an older version of GitLab, this will also determine whether the bug is fixed in a more recent version. --> ### What is the current *bug* behavior? <!-- Describe what actually happens. --> 500 Error is received when clicking on `Add Synchronization` ### What is the expected *correct* behavior? <!-- Describe what you should see instead. --> The LDAP Access Dropdown should have a default value like before, OR the POST request should not be completed and a message should be displayed in the UI that LDAP Access must be selected. ### Relevant logs and/or screenshots <!-- Paste any relevant logs - please use code blocks (```) to format console output, logs, and code as it's tough to read otherwise. --> 16.10 (LDAP Access Dropdown has default value):  17.4.1 (LDAP Access Dropdown DOES NOT have a default value):  ### Output of checks <!-- If you are reporting a bug on GitLab.com, uncomment below --> <!-- This bug happens on GitLab.com --> <!-- and uncomment below if you have /label privileges --> <!-- /label ~"reproduced on GitLab.com" --> <!-- or follow up with an issue comment of `@gitlab-bot label ~"reproduced on GitLab.com"` if you do not --> #### Results of GitLab environment info <!-- Input any relevant GitLab environment information if needed. --> <details> <summary>Expand for output related to GitLab environment info</summary> <pre> (For installations with omnibus-gitlab package run and paste the output of: `sudo gitlab-rake gitlab:env:info`) (For installations from source run and paste the output of: `sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production`) </pre> </details> #### Results of GitLab application Check <!-- Input any relevant GitLab application check information if needed. --> <details> <summary>Expand for output related to the GitLab application check</summary> <pre> (For installations with omnibus-gitlab package run and paste the output of: `sudo gitlab-rake gitlab:check SANITIZE=true`) (For installations from source run and paste the output of: `sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true`) (we will only investigate if the tests are passing) </pre> </details> ### Possible fixes <!-- If you can, link to the line of code that might be responsible for the problem. --> <!-- If you don't have /label privileges, follow up with an issue comment of `@gitlab-bot label ~"type::bug"` -->