Issue Summary

Using POST REST API endpoint /rest/api/1.0/projects/{projectKey}/repos/{repositorySlug}/labels running many requests simultaneously might cause duplicated label names exist in bb_label table.

Steps to Reproduce

1. Step 1
   Run multiple POST requests simultaneously to /rest/api/1.0/projects/{projectKey}/repos/{repositorySlug}/labels with the same label name but against different repositories.

Expected Results

• Only one entry is created in the bb_label table.
• Multiple entries are created in the bb_label_mapping table.
• All the repositories are labeled with the same label.

Actual Results

• More than one entry are created in the bb_label table.
• Only one repository is labeled.

The below exception is thrown in the atlassian-bitbucket.log file:

2021-05-18 10:45:43,332 DEBUG [https-jsse-nio-8443-exec-1] bbuser @1X5NFHEx846x94752x0 1z6x10k 127.0.0.1 "POST /rest/api/latest/projects/PROJ_name/repos/repo_name/labels HTTP/1.1" c.a.s.i.r.e.ServiceExceptionMapper Mapping ServiceException to REST response 500
com.atlassian.bitbucket.DataStoreException: A database error has occurred.
..
Caused by: org.hibernate.NonUniqueResultException: query did not return a unique result: 3

There is no unique constraint on the bb_label.name, which would probably prevent that issue.

Workaround

Currently, there is no known workaround for this behavior. A workaround will be added here when available