Upgrade Poetry installation

[sondrelg]

Type of changes

• Bug fix

Checklist

• I've run the latest black with default args on new code.
• I've updated CHANGELOG.md and CONTRIBUTORS.md where appropriate.
• I've added tests for new code.
• I accept that @willmcgugan may be pedantic in the code review.

Description

Version 1.1.6 of the install-poetry action is now compatible with the Python 3.10 pre-releases, so upgrading the version here should fix the issue referenced in #1216 🙂

Extra context

Unfortunately, while the original issue there is fixed, there seems to be another unrelated issue blocking the project from actually adding the 3.10 beta release into the matrix.

See this run, which outputs:

Installing dependencies from lock file

  SolverProblemError

  The current project's Python requirement (3.10.0b1) is not compatible with some of the required packages Python requirement:
    - dataclasses requires Python >=3.6, <3.7, so it will not be satisfied for Python 3.10.0b1
  
  Because no versions of black match >20.8b1,<21.0
   and black (20.8b1) depends on dataclasses (>=0.6), black (>=20.8b1,<21.0) requires dataclasses (>=0.6).
  Because dataclasses (0.8) requires Python >=3.6, <3.7
   and no versions of dataclasses match >=0.6,<0.8 || >0.8, dataclasses is forbidden.
  Thus, black is forbidden.
  So, because rich depends on black (^20.8b1), version solving failed.

I might be missing something obvious here, but this seems like an already resolved issue (see python-poetry/poetry#1413), and the fix seems to be using notation to tell Poetry that the dataclasses dependency is only relevant on certain Python versions (3.6), which the current pyproject.toml already seems to be doing.

If this really was a problem with the Python version I would expect version 3.7-3.9 to also fail this validation, so I wonder if Poetry has a bug tied to versioning of pre-releases somehow.

[codecov]

Codecov Report

Merging #1252 (0933eea) into master (c2f40e0) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1252   +/-   ##
=======================================
  Coverage   99.82%   99.82%           
=======================================
  Files          69       69           
  Lines        6410     6410           
=======================================
  Hits         6399     6399           
  Misses         11       11           

Flag	Coverage Δ
unittests	99.82% <ø> (ø)

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[sondrelg]

This is unintentionally possibly a little confusing. Just to clarify - the version parameter here specifies the Poetry version, while the @1.1.6 specifies the action version. They just happen to be the same.

[sondrelg]

Ran into some problems with the old setup, so switched from installing dependencies directly inside the runner environment, to installing dependencies to a venv and activating the venv in consequent steps.

Just for context, instead of source $VENV, we could have used source .venv/bin/activate, but since there's a windows combination in the matrix you would need to introduce conditional steps; on Windows you'd want ~source .venv/scripts/activate.

The $VENV environment variable is set inside the install-poetry action so upstream workflows don't need to worry about which OS you're on 🙂

[willmcgugan]

Thanks!