Opening a GitHub PR to a specific branch fails since update

[matt-sanders]

Describe the bug
I've recently upgraded LazyGit from 0.38.2 to 0.43.1. On 0.38.2 I would create a pull request to a specific branch using O, select my branch, and press enter. This would open a url like this: https://github.com/<org>/<repo>/compare/<base>...<compare>?expand=1. Since the update, I've noticed that my options all contain origin/ at the beginning of the base. This results in the following URL: https://github.com/<org>/<repo>/compare/origin%2F<base>...<compare>?expand=1 and GitHub gives me a page saying there is nothing to compare. If I remove the origin%2F then it works as expected.

Is this maybe a config that's changed recently?

To Reproduce
Steps to reproduce the behavior:

1. Open LazyGit in a directory with an existing git repo with a remote named "origin" hosted on GitHub.
2. Create a new branch, push some changes
3. Press O to open the "View create pull request options" menu
4. Choose the second option "Select branch"
5. Select a branch, they should all be prefixed here with origin/ and press enter
6. Notice the page from GitHub saying "nothing to compare"

Expected behavior
It should open a PR creation page correctly.

Version info:
commit=, build date=, build source=homebrew, version=0.43.1, os=darwin, arch=arm64, git version=2.39.3 (Apple Git-145)
git version 2.39.3 (Apple Git-145)

[mark2185]

Just out of curiosity, is this a PR across forks?

The assumption is that the original repo is on the origin remote, whilst the fork is on upstream, if I'm not mistaken.

[matt-sanders]

No this is not across forks.

[ricardoprato]

I have the same problem with bitbucket