Regression: No longer possible to configure JIRA integration without username and password
Summary
We make use of the JIRA integration, but don't want GitLab update anything in JIRA (We use the 'Git integration for JIRA' plugin). But all the links to issues should work, so essentially read-only. This was always easily possible for us by activating the integration but not filling in a username or password.
There seems to be a regression, at least in 9.4 and 9.5, where this is no longer possible. We're now stuck with existing projects which have the integration enabled where we can't update it, and new ones where we can't activate it.
The last version with which we're certain this still worked correctly is 9.0.
Steps to reproduce
Go to settings -> integrations -> JIRA Tick 'Activate' and configure the Web URL Do not fill in a username or password Press 'Test settings and save changes'
What is the current bug behavior?
Saving not possible because username and password are required fields
What is the expected correct behavior?
Saving and activating the integration succeeds when username and password are left empty
Possible fixes
Only check the fields if it has a non-empty value.