_socket.py: fix for systems where AI_NUMERICSERV is not defined

[barracuda156]

Rationale: on some platforms AI_NUMERICSERV may not be defined. In particular, old versions of macOS, possibly some other. While affected users are probably few, it is a trivial fix, which makes trio usable (for example, yewtube app works then).

Credits to @CoolCat467
Closes: #3133

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.62%. Comparing base (a32de81) to head (5260922).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3135   +/-   ##
=======================================
  Coverage   99.62%   99.62%           
=======================================
  Files         122      122           
  Lines       18357    18358    +1     
  Branches     1221     1221           
=======================================
+ Hits        18289    18290    +1     
  Misses         47       47           
  Partials       21       21           

Files with missing lines	Coverage Δ
src/trio/_socket.py	100.00% <100.00%> (ø)

[CoolCat467]

Looks good, but needs newsfragment (that is why continuous integration is failing). newsfragments folder's README file has more information.

[barracuda156]

@CoolCat467 That one CI which fails is unrelated, right?

[A5rocks]

@CoolCat467 That one CI which fails is unrelated, right?

Docs are failing because your newsfragment is using markdown not rST. Try doing socket.AI_NUMERICSERV instead of AI_NUMERICSERV (for the automatic linking) or doubling the backticks.

It's a bit confusing because the logs show two warnings, but the one you should care about is:

/home/docs/checkouts/readthedocs.org/user_builds/trio/checkouts/3135/docs/source/history.rst:42: WARNING: py:obj reference target not found: AI_NUMERICSERV [ref.obj]

I don't think the other one makes it fail, though I may be wrong.

[jakkdl]

I think you need to be a bit more specific here, otherwise future people that stumble on this comment will have to do a bunch of research to figure out why/when it might be missing. And as I said in the issue, perhaps even a note on why it's needed despite being deprecated since a decade+

[A5rocks]

Maybe just linking the issue will work? That has info.

[A5rocks]

@barracuda156 could you fix this? I think this is the only problem before merging.

(well, barring rejecting this whole change on basis of it being something we cannot test for a system we could not support. IMO this change is fine but @jakkdl didn't respond to the response you left on the issue.)