setup-python@v6 with python-version: "3.x" installs pre-release Python 3.14.2 instead of latest stable version

[coaxial]

Description:
When specifying python-version: "3.x" in actions/setup-python@v6, the action resolves and installs Python 3.14.2—even though this version currently has only prerelease (alpha/beta) releases, and the documentation states that prereleases should not be installed unless allow-prereleases: true is set. This behavior was observed on GitHub-hosted runners with the provided configuration, and no explicit allow-prereleases: true was present.

Action version:
actions/setup-python@v6

Platform:

• Ubuntu
• macOS
• Windows

Runner type:

• Hosted
• Self-hosted

Tools version:

• 3.14.2
• (expected: 3.13.x or latest stable 3.x)

Repro steps:
Provide the following in a workflow job:

- uses: actions/setup-python@v6
  with:
    python-version: "3.x"

Observed in the job log:

Run actions/setup-python@v6
Installed versions
  Successfully set up CPython (3.14.2)

Expected behavior:
actions/setup-python should only install stable production releases unless allow-prereleases: true is set (according to the documentation). With python-version: "3.x", it should resolve to the latest stable 3.x, such as 3.13.x.

Actual behavior:
The action installed Python 3.14.2, which is not a stable release at the time of writing. This could break CI environments expecting stable releases only.

[v-gowridurgad]

Hello @coaxial 👋
Thank you for reporting this issue. We will investigate it and get back to you as soon as we have some feedback.

[v-gowridurgad]

Hi @coaxial, CPython 3.14.2 is a stable patch release, not a pre-release. With python-version: "3.x", the action selects the latest stable 3.* version available at runtime, which is currently 3.14.2. For reference, see the Ubuntu runner images docs.

The allow-prereleases option only applies when specifying an exact minor version (like "3.14") before a stable release exists; it allows pre-release versions to be installed in that case. It does not affect the "3.x" shorthand, which always resolves to the latest stable release. For more details, see Allow Pre-Releases.

I hope this clarifies things. Please feel free to reach out if you have any other questions or concerns.

[coaxial]

Thanks, I got confused and thought 3.14 wasn not a stable release. I think this issue can be closed then, thanks for the quick turnaround!