Re: Ping^2 Re: Use gen-libm-test.py to generate ulps table for manual

[Joseph Myers <joseph at codesourcery dot com>]

On Mon, 1 Oct 2018, Carlos O'Donell wrote:

> If you could write up the following:
> 
> * Exact version of python to use.

Any non-EOL Python 3 series.  So 3.4 or later at present, 3.5 or later 
could be required from 2019-03-16 (but that doesn't mean we have to 
increase the requirement then, if there aren't any new features we want to 
use), 3.6 or later could be required from 2020-09-13, as per the table at 
<https://devguide.python.org/>.

> * Exact set of imports we need.

Only modules in the Python (3.4) standard library, and excluding modules 
such as XML, database and UI libraries that depend on external libraries.  
I don't think we need anything depending on OpenSSL (hashlib appears to 
work without it, in Python 3.7, and we probably don't need hashlib 
anyway), but it's possible there may be dependencies on libffi - however, 
I think it's likely we can avoid ctypes which is what brings in the libffi 
dependency, and indirect dependencies on it from e.g. multiprocessing.

I think trying to list exhaustively exactly which modules may be used is a 
bad idea, since there are lots of pure-Python modules in the standard 
library without any external C library dependencies (direct or indirect) 
and it's hard to predict exactly which could be useful at some point.  
gen-libm-test.py uses argparse, collections, os (after the present patch 
that would require it to build the manual) and re.  The scripts used in 
the conform/ tests (not of course strictly relevant to build requirements, 
exact in regard to what tests can use unconditionally rather than needing 
to be conditionally UNSUPPORTED) also use shutil, subprocess, tempfile.  I 
expect there would be plenty more pure-Python standard library modules 
that would turn out to be useful for some particular script.

-- 
Joseph S. Myers
joseph@codesourcery.com