Inline the pre-commit action in the code quality jobs

[albertvillanova]

This PR replaces the third party pre-commit/action with the four steps it is made of, so that the code quality jobs stop emitting a Node.js deprecation warning and no longer depend on an action that is no longer developed.

Motivation

Every run of the code quality job produces this warning:

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/cache@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

It is the only annotation on the job. The cause is not one of our pins: pre-commit/action internally uses actions/cache@v4, which declares using: 'node20', while actions/cache v6 declares using: 'node24'.

That reference is out of our reach. It lives inside the third party action, so Dependabot cannot bump it, and pinning pre-commit/action to a newer SHA would not help either, because upstream has not updated it. Upstream is explicit that it will not:

this action is in maintenance-only mode and will not be accepting new features

So as long as we consume the action, the warning stays, and the runners are being forced onto Node.js 24 anyway. The only way to control that reference is to stop going through the action.

There is little to lose by doing so, because the action is a thin wrapper. This is its entire definition:

runs:
  using: composite
  steps:
  - run: python -m pip install pre-commit
    shell: bash
  - run: python -m pip freeze --local
    shell: bash
  - uses: actions/cache@v4
    with:
      path: ~/.cache/pre-commit
      key: pre-commit-3|${{ env.pythonLocation }}|${{ hashFiles('.pre-commit-config.yaml') }}
  - run: pre-commit run --show-diff-on-failure --color=always ${{ inputs.extra_args }}
    shell: bash

Four steps, one of which is a pip freeze debug call. Inlining it removes a dependency rather than adding one, and it lets us pin actions/cache by SHA like every other action in the repository. As a nested reference, actions/cache@v4 was in fact the only mutable action ref we were still resolving in these jobs.

Solution

Inline the steps that matter, cache, install and run, and drop the pip freeze debug step, keeping the same one step per action granularity as the rest of our workflows. Behaviour is otherwise unchanged: same pre-commit run --all-files --show-diff-on-failure --color=always invocation, and the cache key is kept identical so existing cache entries stay valid.

Changes

• Replace pre-commit/action with a cache step, an install step and a run step in the code quality job of the tests and experimental tests workflows
• Pin actions/cache to v6.1.0, which targets Node.js 24

---

Note

Low Risk
CI-only workflow change with equivalent pre-commit behavior; no application or security logic is affected.

Overview
Replaces the unmaintained pre-commit/action in the code quality jobs of tests.yml and tests-experimental.yml with explicit cache, install, and run steps.

Pins actions/cache to v6.1.0 (Node 24) so the jobs no longer inherit the action’s nested actions/cache@v4 Node 20 deprecation. Pre-commit invocation and cache key stay the same.

^{Reviewed by Cursor Bugbot for commit 83566d1. Bugbot is set up for automated code reviews on this repo. Configure here.}

[bot-ci-comment]

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