[Distutils] reproducible builds

[Thomas Kluyver]

On Mon, Mar 20, 2017, at 01:02 PM, Robin Becker wrote:
> Well now I am confused. The date / times mentioned in the debian patch
> are those 
> we force into the documents produced by the reportlab package when it is
> used.
> 
> They would not normally be part of the package itself. Although the
> reportlab 
> documentation is available in the source I'm fairly sure we don't include
> it in 
> the wheels.

I'm guessing, but I imagine that Debian may be using reportlab in the
builds of other packages, to build documentation. It's normal for Debian
packages to include built docs, unlike wheels. So they would want it to
create PDFs reproducibly, but the PDFs generated in your test suite
probably don't matter.

> I guess the algorithm variation across pythons would make dictionary order quite variable.

For a Python based tool, I think it's reasonable that reproducing a
build requires running with the same version of Python.

The requirement would be that, with enough information about the build
environment, you *can* produce an identical PDF. It needn't (AFAIK) be
identical every time anyone builds it.

Thomas