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Make sure that Jira is integrated with your Bitbucket Server instance. If not, please take all the necessary steps to integrate it. Here is how to do ithttps://confluence.atlassian.com/bitbucketserver/link-bitbucket-with-jira-776640408.html. This step requires (global) system admin permission.
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Enable both the merge check and post hook for a Bitbucket Server project as described above
Create at least 2 pull requests using the same Jira id (here is how to link work to Jira issues https://support.atlassian.com/jira-software-cloud/docs/reference-issues-in-your-development-work/)
Make sure one of pull requests cannot be merged in order to check that none of the pull requests can be merged
Observe that none of the pull requests can be merged
Resolve all issues and have all pull requests ready to be merged
Merge any of the pull requests
Observe that the rest of the pull requests have been merged by the post hook
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