Updating an emulator

Add a remote repository for the upstream vendor

Assuming you already have the repository checked out, add a new remote for the upstream:

$ git remote add vendor https://github.com/visualboyadvance-m/visualboyadvance-m

Checkout the source branch

Each repository should already have a source branch that is the state of the vendor code at the last point it was upgraded. Create a branch off that, and merge the target tag from the vendor repository:

$ git checkout -b source origin/source
$ git fetch vendor
$ git rebase v2.1.4
  OR
$ git rebase vendor/master

Make sure to build and test the unmodified emulator before proceeding to the next step.

Integrate the changes

Create a new merge branch, test, and create the PR.

$ git checkout master
$ git checkout -b vendor_2.1.4
$ git merge source

Build and test, making sure to note any new functionality that may have to be gated behind disable hardcore warnings.

Create the PR

Push the changes and create the PR. Make sure to push the tags as well as many builds generate version information from them.

$ git push -u origin vendor_2.1.4
$ git push --tags
$ git checkout source
$ git push