Hi Chris!
On Mon, Feb 27, 2023 at 07:53:12AM +0000, Chris Lamb wrote:
> Whilst working on the Reproducible Builds effort [0] we noticed
> that pyproject-api could not be built reproducibly.
That's unfortunate! Sorry for not realizing it before you did.
For what it's worth, this package was uploaded as a new dependency of
tox 4. It looks like tox 4.4.6-1 (uploaded to experimental last week)
suffers from the same issue as well. I will handle it there as soon as
we conclude our resolution of this one -- no need for a separate bug :)
> This is because the documentation embeds the current date in the
> build system's current timezone. A patch is attached that uses
> SOURCE_DATE_EPOCH [1] if available.
>
> ...
>
> + html_theme = "furo"
> +-html_title, html_last_updated_fmt = "pyproject-api docs",
> datetime.now().isoformat()
> ++build_date = datetime.utcfromtimestamp(
> ++ int(os.environ.get('SOURCE_DATE_EPOCH', time.time()))
> ++)
> ++html_title, html_last_updated_fmt = "pyproject-api docs",
> build_date.isoformat()
Looking at Sphinx's documentation, it looks like html_last_updated_fmt,
as the name hints, is supposed to be the format string, not the actual
date. (A literal date works as a format because anything that's not
percent-encoded is passed on unmodified. So I think that's just a happy
accident.)
I checked the Sphinx source code, and it looks like the string is used
in prepare_writing() from builders/html/__init__.py, which in turn
passes it on as an argument to format_date() from util/i18n.py. It looks
like format_date() has support for SOURCE_DATE_EPOCH.
So from what I can tell, a much simpler patch would be to set
html_last_updated_fmt to "%Y-%m-%dT%H:%M:%S.%f" for the equivalent ISO
8601 string (or even something with less accuracy) -- no need to fiddle
with the datetime module, or SOURCE_DATE_EPOCH at all.
I know you've gone to great lengths to make Sphinx docs reproducible
across the board, so I'm leaning on your experience to let me know if
I'm missing something here before I patch it locally and pass it on to
the two upstream projects. Looking forward to your feedback.
Best,
Faidon
