Prevent python from automatically downloading dependencies

[Kurt Hindenburg]

> On Nov 8, 2017, at 12:13 PM, Rainer Müller <raimue at macports.org> wrote:
> 
> On 2017-11-08 17:32, Ryan Schmidt wrote:
>> 
>> On Nov 8, 2017, at 08:24, Kurt Hindenburg wrote:
>> 
>>> On Jun 25, 2017, at 1:52 AM, Joshua Root wrote:
>>> 
>>>> On 2017-6-25 12:27 , Ryan Schmidt wrote:
>>>>> We often have this problem that we forget to specify dependencies in a python port. Python (setuptools?) helpfully automatically downloads a temporary copy of the dependency to use, so we may not notice this until committing the port, at which point if we're looking at the buildbot logs we might notice that it fails to build on older OS versions because of SSL problems.
>>>>> Here's an example:
>>>>> https://build.macports.org/builders/ports-10.7_x86_64_legacy-builder/builds/37372
>>>>> Is there a way we can tell python in the python portgroup that it should not attempt to automatically download dependencies, so that we would discover these problems earlier?
>>>> 
>>>> According to the setuptools docs, easy_install at least has a --no-deps flag, and if that doesn't work, there's a --allow-hosts flag to which you can pass None to prevent all downloading. Someone would have to test whether these work when passed to setup.py as well.
>>>> 
>>>> - Josh
>>> 
>>> i looked at this briefly.  I don’t think it is possible to pass easy_install options through setuptools.  The only way I could get it to work was to either 1) append to ports setup.cfg; 2) append/create system wide distutils.cfg.  Then you’d have to somehow revert upon failure/success.  I don’t see how this would work in practice.
>>> 
>>> Kurt
>>> 
>>> [easy_install]
>>> allow_hosts = None
>> 
>> These two lines are what would be appended to either of those files? What problems do you foresee if we would have the python portgroup automatically append those lines to the port's setup.cfg?
> 
> Could we place this into ${workdir}/.home/.pydistutils.cfg, which is in
> the HOME for the macports user? As I understand the documentation linked
> below, this file should be read by default. This could be done
> unconditionally instead of editing the source files of the port.
> 
> https://docs.python.org/2/install/index.html#location-and-names-of-config-files
> 
> Rainer

Ok, I didn’t realize ${workdir}/.home would be used.  It works as expected if the 2 lines are in that file.  Also note that the errors are verbose and perhaps not clear to the user what the issue is.
  I’ll see about putting the code in the python PG and create a pull request for comments.

 Thanks
   Kurt