[AstroPy] External packages in astropy

[Olе Streicher]

Thomas Robitaille <thomas.robitaille at gmail.com> writes:
>> This could be handled outside of wcslib by changing these values before
>> passing them in, which would give us compatibility with vanilla wcslib
>> -- that might be a reasonable solution.

> I agree that if we could make it so that we ensure that we can use the
> vanilla WCS and dealing with and stripping out the SIP stuff before
> passing the header to wcslib, this would be a good solution that would
> make most people happy. 

I would be happy with this solution in the moment (... until we get a
wcslib that fits to more situations natively).

> Then wcslib could be moved to cextern, and disabled in package
> managers than include wcslib (with the caveat that only recent
> versions of wcslib would be supported due to recent bug fixes). Maybe
> Astropy could check the version of wcslib being used and raise an
> error if it is too old?

Hmm. I think that the problem mainly occurres when using packaged
versions of pywcs or astropy. This means that usually the packages get
updated automatically, so the newest version would be used. And, the
packager can specify a required version when the package is being built
or run. So, I would not see a problem here. I would also tend to include
a bugfix patch into a current version of wcslib until it gets fixed
upstream. Having a version check would kill this attempt.

wcslib also does not provide runtime version information; so version
checking at runtime would not work anyway.

Best regards

Ole