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This will be very helpful and needed.

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Developers keep merging code before linking the Jira and we have no way to add the relationship of Jira to PR afterwards. Please address this concern.

319ba8c4e46e perhaps this is hiding the main problem that there is no way other than PR titles to link a PR to a Jira issue.

It's been 6 1/2 years since this request was opened. When will it get implemented?

There are genuine end-user use-cases where this solves problems after a pull request was perhaps merged a little too quickly without someone realizing that something as simple as the Jira issue ID not being in the title, so now the Jira integration won't work.

Let's go Atlassian!!!

PS: If there are reasons why certain organizations DON'T want editing to be possible, create a project or repository-based setting for this. ideally as a future option so that the majority of users who DO want this can get it ASAP.

This issue has gathered enough interest to be moved automatically to Reviewing status, where it will be reviewed to someone in the relevant product development team and moved on to the appropriate status.

Seriously...why you can't edit?!?!?! 
And also why sometimes it proposes closing the branch, others it proposes deleting it?
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Voted for this.  It's important to be able to change the Jira number on a PR, even after it's been merged.  I'm not sure why validation to prevent this would have been implemented in the first place.

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