SOLVED - Nic's final 'test', creating a screen with only 1 field, associating it with the transition, then removing the single field after the fact seems to be a workaround for this issue. More details found down in the post, if you're seeing this issue.
Thanks Nic!
I'm not sure why I didn't try this myself...
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I'm a fairly experienced JIRA admin - and I've never run into this problem before.
I've changed a workflow recently, making a transition that allowed closed bugs to be reopened. This isn't generally a complicated change - however, I've found a strange issue.
If I don't assign a screen, the transition occurs as expected (no screen)
If I add an existing screen it appears as expected (the existing screen renders)
If I create a new screen for that transition but don't add any fields, no screen appears.
If I create a new screen that has assignee as the field, no screen appears.
I've been following this article: https://confluence.atlassian.com/jirakb/how-to-add-a-comment-during-a-transition-779160682.html
- it indicates that creating a screen with no fields should render just a comment field, however, I am finding that nothing appears, as though I have not assigned any screen to that transition.
There is no option to just add the comment field.
I'm a bit unsure why I can assign an existing screen and it's fine, but newly created screens completely fail to appear.
Anyone else able to reproduce this issue?
I've tried validators to ensure a comment is added, it did not work.