We want to assume that all the Python we write is running with at least Python 3.5; configure checks that for our scripts, but Sphinx extensions run with whatever Python version sphinx-build itself is using. At the moment our Sphinx extensions all work under Python 2, but the one I'm working on for handling parsing QAPI docs out of the JSON is going to want to include some of the scripts/qapi Python which is more complicated and definitely now 3-only. In any case, allowing some bits of our Python code to run under Python 2 is setting a beartrap for our future selves. It's nicer to fail cleanly rather than let users stumble into corner cases we don't test and don't want to support even if they happen to work today.
Patch 1 adds a --sphinx-build=/path/to/binary option, so that if the user has a system where the default 'sphinx-build' on the $PATH is Python 2 they can tell configure to use a different one. Patch 2 makes the Sphinx conf.py fail for old Pythons, and makes configure handle and present the error to the user. Alex: do you have a way to test this patchset with readthedocs before it hits master? I'm not sure what version of Python their sphinx-build is using. If we need to I think we can force a Python version with a .readthedocs.yml file in our git repo: https://docs.readthedocs.io/en/stable/config-file/v2.html but if they default to a new enough Python anyway then we needn't bother. thanks -- PMM Peter Maydell (2): configure: Allow user to specify sphinx-build binary configure: Check that sphinx-build is using Python 3 configure | 22 +++++++++++++++++++--- Makefile | 2 +- docs/conf.py | 10 ++++++++++ 3 files changed, 30 insertions(+), 4 deletions(-) -- 2.20.1
