Use pip install --report over pip-compile

[mitsuhiko]

This hack uses a pip that is temporarily added to the virtualenv as an alternative over pip-compile. It does not fully address #82 but it covers some common cases.

Before merging this, some tests should be added to establish some baseline of installable packages.

Things to do before merge:

• add tests for some common scenarios
• restore --upgrade support for single packages

[mitsuhiko]

One significant downside of this approach over pip-tools is that the latter can resolve bad constraints. So for instance if you pin a dependency to too low version, it will manage to break that pin. pip on the other hand just bails hard

INFO: pip is looking at multiple versions of flask to determine which version is compatible with other requirements. This could take a while.
…

The conflict is caused by:
    flask 2.3.2 depends on Werkzeug>=2.3.3
    The user requested (constraint) werkzeug==2.2.0

[mitsuhiko]

I don't think that this is the path to go given the restrictions of this approach.

[davegaeddert]

@mitsuhiko just curious, what's the gist of the issues? Only the resolution thing you mentioned above, or more than that?

[mitsuhiko]

@davegaeddert one is the issue that it can’t resolve outdated pins, another is that it’s unclear how to upgrade single packages