Anki/pip

To achieve reproducible builds we use pip-tools to lock packages to a particular version. Sadly this is complicated by the fact that Python can only tell us which transitive dependencies are required by actually installing packages, and if you run pip-tools on a Mac or Linux machine, it will miss packages that are required on Windows and vice versa.

So we're stuck manually merging dependencies for now. To update deps:

• run 'bazel run update' to update requirements.txt for the current platform
• consult the git diff, and manually merge the changes, undoing the removal of items pinned on other platforms
• repeat the process on the other platform
• run the tests to ensure nothing has broken on either platform
• commit the changes to requirements.txt

At the time of writing, Macs and Linux machines have identical output - it is only Windows that differs. But we should not assume that will always be the case.