Summary

Branches with names containing non-UTF-8 or special characters cannot be deleted from the Bitbucket UI or with the git push <remote> --delete <branch> command.

Solution

Here are the procedures to follow to remove branches with non-UTF-8 or special characters:

Solution 1

• Get the repository location on disk for the affected repo. In the Bitbucket UI, go the Repository Settings > Repository details and look for the "Location on disk" value.
• On the server, go to the location on disk

• Run the following commands to search for the specific branch to delete and convert it to Hex values:

  git branch -a | grep <pattern_to_match_the_branch> | hexdump -C

  This will return Hex values.

  For example: branch is: "test�"
  To search and convert it to Hex:
  

  git branch -a | grep "test" | hexdump -C

  This will return:
  

  00000000  20 20 74 65 73 74 a1 34 0a                    |  test...|

• Analyze the output
  In the sample above:

  "20 20" are for 2 spaces
  "74 65 73 74" are the Hex values for "test"
  "a1 34" are for the character
  "0a" is for the line feed character

• Use the relevant Hex values for the Git command to delete the branch.
  For the sample above, to delete the branch from the remote:

  git push origin --delete $'test\xa1\x34'

Solution 2

These procedures will modify refs on the server. Make sure to create a backup of the repository before proceeding.

1. local: Pull or clone the repository from the remote to ensure that the ref objects and commit hashes on the local copy are up to date
2. server: Identify the location on disk for the affected repo. In the Bitbucket UI, go the Repository Settings > Repository details and look for the "Location on disk" value.
3. server: Create a backup copy of the repo
4. server: Go to the location on disk and check if the bad ref is in the refs/head/ folder as a file (i.e. refs/head/<refname>) or inside the /packed-refs file.
5. server: If the ref is inside the /packed-refs file, we will need to shut down Bitbucket before making any changes. 
   While shutdown, edit the /packed-refs file and remove the bad line.
6. server: If the ref is in the refs/head/ folder as a file (i.e. refs/head/<refname>), delete the file
   At this point, the refs are now removed from the server.
7. local: Open the .git folder in the local repository
8. local: Check if the bad ref is in the refs/head/ folder as a file (i.e. refs/head/<refname>) or inside the /packed-refs file
9. local: If the ref is inside the /packed-refs file delete the line containing the bad ref
10. local: If the ref is in the refs/head/ folder as a file (i.e. refs/head/<refname>), delete the file
11. local: Open the config file and find the bad branch name and delete the section with the bad branch.

12. local: Create a new branch on the same commit hash that the bad ref was pointing to.
    For example:

    git checkout <commit hash>
    git branch newname

13. local: Push the branch to the remote.
    

The remote and local copy should now have the correct new refs. However, old clones/other users may have the old bad ref.
Please let others know about the change and share the procedures performed on the local copy of the repo.