Whilst making Travis store the pip cache saves us from having to
download the packages from PyPI each time, the vast majority of time
spent during Travis run setup is compiling the packages that contain
binary components. As such, let's try caching the virtualenv itself so
we don't have to repeat this each time. We no longer get Travis to
store the pip cache since it will only be used when the virtualenv is
first created & will bloat the Travis cache archive that has to be
downloaded from AWS at the start of each run.
The packages in this file are already a mixture of pure and compiled
packages. It's not worth moving the pure packages to checked-in.txt,
since we'll eventually be removing checked-in.txt and the associated
vendor/ and moving everything in there to this file. As such, common.txt
more accurately reflects the purpose of this file.
Travis |cache: pip| should do this for us, except it only works if we
don't set our own install step, due to:
https://github.com/travis-ci/travis-ci/issues/3239
Instead, let's manually specify the directory to cache.
flake8 is pyflakes+pep8. In a later PR I'll add a mention of it to the
docs - particularly how to set it up as a local git commit hook, but for
now I'm just keen to not regress the passing flake8 run. We may also
need to further tweak the ignore settings in setup.cfg if we find
certain warning types to be too annoying.
Dependencies in pure.txt are used directly from the in-repo vendor
directory, so we should not waste time installing them in the virtualenv
during Travis runs.
Ed Morley
Cameron Dawson
Jonathan French
mdoglio
Jonathan Eads