PyPy is an alternative Python implementation. While it does replace a large part of the interpreter, a large part of the standard library is shared with CPython. As a result, PyPy is frequently affected by the same vulnerabilities as CPython, and we have to backport security fixes to it.
Backporting security fixes inside CPython is relatively easy. All main Python branches are in a single repository, so it’s just a matter of cherry-picking the commits. Normally, you can easily move patches between two related git repositories using git-style patches but this isn’t going to work for two repositories with unrelated histories.
Does this mean manually patching PyPy and rewriting commit messages by hand? Luckily, there’s a relatively simple git am trick that can help you avoid that.
Continue reading “Moving commits between independent git histories”