Removed version spec from psycopg2-binary

[jaap3]

The earliest version of psycopg2-binary is 2.7.3.2 (https://pypi.org/project/psycopg2-binary/#history) so there's no reason to specify a minimal version here.

[timgraham]

Someone brought this up before but I think it's better to keep the requirement for documentation purposes in case anyone is using the non-binary package.

[jaap3]

Ah, maybe it would be clearer to change the content of this file to something like this then:

# psycopg2>=2.5.4
psycopg2-binary

It's not obvious that the usage of a non-existent minimal version of one package is used to signal a minimum version of an alternate version of that package.

(I force pushed this change to my branch, but it doesn't show up here)

[timgraham]

I don't see it as a big source of confusion that requires adding a commit in Django's history, but tell me if it tripped you up.

[jaap3]

It did cause some confusion when I tried to run Django's test suite in a docker python-alpine based container.

pip doesn't actually install a binary/wheel for the psycopg2-binary package on that specific flavour of linux and instead downloads the source tarball. This in turn causes an error because none of the tools required to build psycopg2 are available in that container.

At first I thought it was caused by trying to install psycopg2, but looking at the requirements file I saw that psycopg2-binary was listed. So then I looked at PyPI and noticed that psycopg2-binary doesn't even have a version < 2.7.3.2.

This caused me to think that somehow the version spec caused pip to install psycopg2. It obviously doesn't, but it did trip me up.

None of this is really Django's fault, psycopg2-binary probably shouldn't list a source tarball on PyPI in the first place. But having a version spec in the requirements file did lead me on a bit of a wild goose chase.

[jaap3]

Related issues in the psycopg2 repository:

psycopg/psycopg2#684
psycopg/psycopg2#761