SPEC 0 Versions Action

A GitHub Action that updates the lower bounds of Python dependencies in pyproject.toml to conform to the SPEC 0 support schedule.

Using the action

Example workflow

Copy the yaml below into .github/workflows/update-spec0.yaml. On each run the action opens a PR updating dependency lower bounds to match the current SPEC 0 schedule.

name: Update SPEC 0 dependencies

on:
  schedule:
    # Day 3 of each quarter. Allows one day buffer after the quarterly schedule release on day 1
    - cron: "0 0 3 1,4,7,10 *"
  workflow_dispatch:

permissions:
  contents: write
  pull-requests: write

jobs:
  update:
    runs-on: ubuntu-latest
    steps:
      - uses: scientific-python/spec0-action@v1

No PAT required. The built-in GITHUB_TOKEN is used by default as long as the workflow has pull-requests: write permission.

Parameters

Input	Required	Default	Description
token	no	GITHUB_TOKEN	Token with pull-requests: write permission to open PRs
project_file_name	no	pyproject.toml	Path to the file to update, relative to repository root
schedule_path	no	—	Path to a custom schedule.json, relative to repository root. Uses the latest release if unset
target_branch	no	main	Branch to open the PR against
create_pr	no	true	Set to false for a dry run
pr_title	no	chore: Drop support for unsupported packages conform SPEC 0	Title of the opened PR
commit_msg	no	chore: Drop support for unsupported packages conform SPEC 0	Commit message for the version update commit
update_all	no	—	If set to a number N, also update non-SPEC0 dependencies to versions released within the last N years (e.g. 2)

For examples of before/after see tests/test_data/pyproject.toml and tests/test_data/pyproject_updated.toml.

Limitations

1. The action only tightens lower bounds and leaves upper bounds untouched. An update can produce an unsolvable environment — for example numpy = ">=1.25.0,<2" becomes numpy = ">=2.0.0,<2". Keeping the environment solvable is out of scope; adjust upper bounds manually if needed.
2. Only pyproject.toml is currently supported.

Maintainer notes

Releasing a new action version

Action versions are git tags only, do not create a GitHub Release for them. GitHub Releases in this repository are reserved for the quarterly schedule data.

git tag v1.x
git push origin v1.x

Schedule releases

The SPEC 0 schedule (schedule.json and schedule.md) is published as a GitHub Release quarterly by the Update SPEC 0 schedule workflow. Releases are tagged schedule-YYYY-QN (e.g. schedule-2026-Q2).

The action always fetches schedule.json from the latest GitHub Release in this repository, which will always be a schedule release as long as action versions are never published as releases.

Bootstrap

Before the first quarterly schedule release exists, the action will fail. To create the initial release, trigger the workflow manually:

1. Go to Actions → Update SPEC 0 schedule
2. Click Run workflow

Subsequent releases are created automatically on the 1st of January, April, July, and October.