python-build

Builds the embedded CPython runtimes (Android, iOS, macOS, Linux, Windows) that serious_python and flet bundle into apps.

manifest.json — the runtime source of truth

manifest.json is the single source of truth for a runtime release. It is used both ways:

• Drives the build. CI reads it to decide which CPython versions to build (the build matrix), so what gets built is exactly what the manifest lists.
• Is published. Each release uploads the same manifest.json as a release asset (with the release date injected), so downstream tools fetch a single, consistent version set by date instead of hand-mirroring versions.

Schema:

{
  "release": "20260611",                  // injected at publish (= release tag)
  "default_python_version": "3.14",
  "dart_bridge_version": "1.2.3",
  "pythons": {
    "3.14": {
      "full_version": "3.14.6",
      "standalone_release_date": "20260610",
      "pyodide_version": "314.0.0",
      "pyodide_platform_tag": "pyemscripten-2026.0-wasm32",
      "android_abis": ["arm64-v8a", "x86_64"],
      "prerelease": false
    }
  }
}

android_abis lists the ABIs package-for-dart.sh builds for this minor — 64-bit first, then armeabi-v7a if the minor still supports 32-bit Android. 3.12 carries all three; 3.13+ are 64-bit-only (PEP 738).

The committed file omits release; the publish step injects it.

Adding or bumping a Python / Pyodide / dart_bridge version

Edit manifest.json and open a PR. The CI matrix updates automatically from it.

Releases

Releases are date-keyed (YYYYMMDD) and cut manually:

1. Run the Build Python Packages workflow via workflow_dispatch with a release_date of YYYYMMDD.
2. CI builds every Python in the manifest matrix, then publishes all per-platform tarballs and manifest.json (with release set) to a GitHub release tagged with that date.

A push without a release_date still exercises the full matrix but publishes no release (per-job artifacts only).

Consumers

• serious_python pins a release date, fetches that release's manifest.json, and generates committed per-platform version tables from it.
• flet fetches the manifest by date for commands that run without serious_python (e.g. flet publish).

See platform-specific notes under android/, darwin/, linux/, and windows/.