[MacPorts] #66825: py39-scrapy @2.7.1 apparently installs without problems, but produces errors when run

[MacPorts]

#66825: py39-scrapy @2.7.1 apparently installs without problems, but produces
errors when run
----------------------------------------+----------------------------
  Reporter:  typonaut                   |      Owner:  kurthindenburg
      Type:  defect                     |     Status:  assigned
  Priority:  Normal                     |  Milestone:
 Component:  ports                      |    Version:  2.8.1
Resolution:                             |   Keywords:
      Port:  py-scrapy py-cryptography  |
----------------------------------------+----------------------------

Comment (by typonaut):

 It seems to me that the test of Python version, or OS version, is not a
 lot of help, because, having a ```python``` >= 2.7 still results in a
 ```scrapy``` that does not run, because the ```cryptography``` version is
 not sufficient.

 From my tests, it appears that ```cryptography``` > 3.3.2 cannot be
 installed on MacOS 10.6, with pip, even if you are running ```python``` >=
 3.9. There may be some other way to install cryptography, but I do not
 know what it is.

 So, upon running ```port install scrapy``` I think you need to ask the
 user into which Python version they wish to install the module. When
 installing the dependencies, the ```cryptography``` install should fail,
 if it is attempting to install a version that the ```scrapy``` install
 does not support. The ```setup.py``` for ```scrapy 2.8.0``` says ```
 "cryptography>=3.4.6"``` – so the ```python 2.7``` test than ends up
 installing ```cryptography 3.3.2``` does not meet that requirement.

 I have checked the versions of ```scrapy``` available on github, and the
 last version that appears to support ```cryptography 3.3.2``` is ```scrapy
 2.7```. So, at the least, if bumping the ```cryptography``` down to
 ```3.3.2``` upon the install, the ```scapy``` should also be downgraded to
 ```2.7``` - with a notice/check to the user in both cases.

 Thanks!

-- 
Ticket URL: <https://trac.macports.org/ticket/66825#comment:8>
MacPorts <https://www.macports.org/>
Ports system for macOS