Improve UsePython to allow installation versions on-flight

[maxim-lobanov]

Problem

Currently, UsePython task just switches versions that are pre-cached on image (example).

It works for the most of the use-cases, because image always contains latest patch version for every major.minor pair.
However, some customers prefer to specify exact version of Python and would like to control it by themselves / freeze specific version. Current implementation of UsePython doesn't allow it.

Proposal

Versions of Python can be installed on-flight from https://github.com/actions/python-versions. This repo distributes versions of Python via GH releases. Also it contains versions-manifest.json as an index of versions.

Installation on-flight is pretty quick and should cover those use-cases. Also it is not a breaking change because task will try to download version only in case if it is not found locally.

The same changes were already done for GitHub Actions task setup-python.
Related PRs:

1. Use GitHub releases to download python versions actions/setup-python#85
2. Tool cache install from a manifest file actions/toolkit#382

[mattip]

This would be very useful for trying out versions of python without waiting for deployment of a new image.

[remyjette]

This would also be really nice for self-hosted agents

For example NuGetToolInstaller@1 will "find, download, and cache a specified version of NuGet." Very easy to use. But UsePythonVersion@0 instead has a whole section in the documentation "How can I configure a self-hosted agent to use this task?" which describes a manual process for setting up a very specific folder structure inside _work/_tool, which then needs to be performed again for each new version.

[github-actions]

This issue is stale because it has been open for 180 days with no activity. Remove the stale label or comment on the issue otherwise this will be closed in 5 days

[hugovk]

Still valid. Would be nice to have this in place for the Python 3.10 release in October.

[hugovk]

Would be nice to have this in place for the Python 3.11 release in October 2022 :)

[DaniilShmelev]

This feature will be released in the next few weeks in [email protected]

[DaniilShmelev]

@maxim-lobanov has noticed an error in the current implementation: #15820 (comment)
We've prepared proposals to fix it, but I'll reopen this ticket for now

[github-actions]

This issue is stale because it has been open for 180 days with no activity. Remove the stale label or comment on the issue otherwise this will be closed in 5 days

[hugovk]

@maxim-lobanov has noticed an error in the current implementation: #15820 (comment) We've prepared proposals to fix it, but I'll reopen this ticket for now

@maxim-lobanov / @DaniilShmelev Did #16217 fix the aforementioned error?

[github-actions]

This issue is stale because it has been open for 180 days with no activity. Remove the stale label or comment on the issue otherwise this will be closed in 5 days

[hugovk]

Awaiting confirmation.

[github-actions]

This issue is stale because it has been open for 180 days with no activity. Remove the stale label or comment on the issue otherwise this will be closed in 5 days

[hugovk]

Would be nice for confirmation for the Python 3.12 release in October 2023.

[github-actions]

This issue is stale because it has been open for 180 days with no activity. Remove the stale label or comment on the issue otherwise this will be closed in 5 days

[hugovk]

Would be nice for confirmation for the Python 3.13 release in October 2024.