Explicit version of ua-parser in requirements

[tsouvarev]

It should be controllable which version of ua-parser is installing

[selwin]

Hi there, you can control it by specifying a requirement file in your project.

[tsouvarev]

@selwin So, it's okay, that ua-parser updated recently and your library was broken? And what if some other library will explicitly require ua-parser<0.4? pip will happily install it and once again your library is broken

[selwin]

@tsouvarev in general, I don't think third party libraries should pin to explicit versions.

For example, I maintain both https://github.com/ui/django-rq and https://github.com/nvie/rq repositories, both require Redis. If both those libraries pin to specific versions of Redis library, this will quickly lead to dependency conflicts that are very hard to resolve. If I update RQ to require redis==2.10.3 and Django-RQ requires redis==2.9.0, what would the user do then?

Anyway, there are pros and cons to each decision. The beauty of open source is that if you don't agree to a decision, you can just fork this repository and choose to use your repo in your requirements file. Your PR only changes a single line of code in setup.py so it shouldn't be too hard to maintain that fork.