How to block a transition on a task without accepted pull request in Stash/Bitbucket ?

Question

I think the title is clear enough 
 I want to block a specific transition if there is no accepted pull request for the task.

I saw the "Unreviewed Code Condition" in Jira, but I don't know if it work with Stach/Bitbucket or only with Crucible.

Jobin Kuruvilla [Adaptavist] · Accepted Answer

The condition only works with Crucible and there is no equivalent for Bitbucket. But if this is a mandatory requirement, maybe you can alter the workflow to use triggers. i.e. Bitbucket will trigger the issue transition after the successful merge.

If you have multiple conditions on the same transition, that will be a problem. You will have to use some JQL conditions, using third party plugins, to figure out that the issue has successful reviews.