pypng is an unlisted dependency

[rpdelaney]

Pretty much the subject.

I installed this with pip3 install --user pyqrcode but got hit with module not found on line 1266 of builder.py: import png. The comments to that file state that pypng is required, so I installed that the same way I installed pyqrcode and now it works.

[agroszer]

Is this intentional? Just add pypng to setup.py install_requires please

[heuer]

We discussed it in the past since I wanted pypng as requirement but Michael said PNG is just one serialization format and wanted to keep it as optional dependency because all other formats work without further dependencies.

It's listed in the setup an extra:

 extras_require = {
   'PNG':  ["pypng>=0.0.13"],

},

To cut a long story short: Yes, it is intentional. ;)

[agroszer]

ok, thx

[rpdelaney]

Optional is fine, but we should consider handling the ImportError, perhaps with a more user-friendly message.

[heuer]

I agree, anyway we cannot do anything about it; see #52

And without solving pypi/warehouse#4121 I am not in the mood to invest any more energy into this project.