Polling branch detection runs even with Bitbucket Server application link added

Summary

With Bitbucket Server linked to Bamboo, the polling branch detection still runs.

Steps to Reproduce

1. Link Bamboo to Bitbucket Server (version 4.0+)
2. Enable branch detection
3. Configure 300s interval for Branch detection in Administration >> Overview >> General configuration

Expected Results

Polling branch detection does not run, and branch detection only responds to changes sent from Bitbucket Server.

Actual Results

Polling does run at the configured interval, and branch detection responds to changes sent from Bitbucket Server as well.

Notes

While this is a bug in Bamboo, all Bamboo versions are susceptible to this if they are integrated with a version of Bitbucket 4.0+.

Workaround

While there is no way to disable the branch detection polling behavior, since we know excessive polling branch detection if you have a large number of repositories can contribute to performance issues – you can safely increase the Bamboo Administration > Overview > General Configuration > Global Branch Detection Interval to a higher value to reduce the impact. Bitbucket branches will still be detected in a timely fashion regardless of this value due to the event based notification from Bitbucket. Please be aware that if you do this and have other types of repositories such as Git / SVN, this will effect branch detection speed.