The symptoms

When trying to open a pull-request, if you run into this error:

The branch into which this pull-request was to be merged: XXX seems to
no longer be present in this repo

(Where XXX is a branch name).

(Here XXX is m2).

This means that the pull-request was opened against a branch on your repo and that this branch no longer exists. Pagure is therefore unable to compute the diff between the sources and the target of the pull-request.

The pull-request is thus inaccessible but remains in the list of open pull-requests.

The solution

The easiest solution to solve this problem is to re-create the target branch in your repo.

This can be done using git simply by doing:

git checkout -b <branch_name>
git push origin <branch_name>

It will create the branch named <branch_name> in pagure, allowing the diff to be computed for that pull-request and thus allowing it to be displayed. It is then up to you to see if this pull-request is still relevant and should be merged or closed.