Issue Summary

• As per the title, whenever a PR is merged using the fast-forward strategy, you get the following error message when trying to revert it:

  Unable to revert pull request
  
  The resulting revert would cause conflicts on one or more files. You will need to resolve these conflicts manually or create a new pull request to revert these changes.
  

• On the console log, we get a 400 with the following response:

  {"type": "error", "error": {"message": "The merge commit doesn't have exactly two parent commits."}}
  

Steps to Reproduce

1. Create a branchB from branchA;
2. Commit your changes to branchB;
3. Open a pull request from branchB to branchA;
4. Merge it using the fast-forward merging strategy;
5. Try to revert the PR;

Expected Results

• The PR should be reverted;

Actual Results

• An error occurs and it is not possible to revert the PR;

Workaround

Even though it is not possible to revert the Pull Request through the Bitbucket UI, it is still possible to do so from the command line:

1. Identify the last commit before branchB was created with

   $ git log

2. Grab the commit SHA and run

   $ git revert <SHA>

3. This might generate a few conflicts that will need to be resolved locally;
4. Commit the changes and push to the remote;