Jira: assign an existing git branch to an issue

ex-Stash developer here.

Yes and no. Creating the branch though the UI is just a convenience. The important thing is that the name contains the JIRA key. If only one developer is working on the branch, it's fairly easy to just rename (delete + add) a branch with the appropriate name.

git checkout old-branch
git push -u origin old-branch:JIRAKEY-1234-something
git push origin :old-branch

Does that help?

Update

As for january 2017 if you have an already exiting branch and you want to attach it to a Jira Issue you can do the following:

1. Checkout to the branch you want to rename

2. Execute the following command
   

   git branch -m JIRA_ISSUE_ID-Whatever

Assuming that mine Jira issue is SO-01 I can do the following:

git branch -m SO-01-Whatever

This will change the name locally, push it to remote with:

git push origin :old_name

Command Syntax

git branch (-m | -M) [<oldbranch>] <newbranch>

Related question for more info