Misleading error message is displayed when creating pull request for a target branch that prevents all changes

Summary

Environment

• Bitbucket 5.3.2 or 5.4.0 (other versions may be affected as well)

Steps to Reproduce

1. On a repo, set up branch permissions to prevent all changes:

a) Select Branch pattern

b) Enter refs/heads/release/*

c) Select Prevent all changes

d) Click Create

2. Edit a file through the Bitbucket Server GUI and make changes to it

3.Click Commit

4. Select Create a pull request for this change

5. As the Branch name enter release/somechange

6. Click Create pull request

Expected Results

A message is displayed informing the user that branch permissions prevent the creation of the branch

Actual Results

The following message is displayed to the user:

A branch with this name already exists. Try another.

Workaround

Remove branch permissions or tell users to create pull requests for other branches than the one with the restrictive permissions applied to it.