Add serious_python:main version [--json] + CI vars from registry

The Dart `_pythonReleases` registry is the source of truth for the
Python version matrix, but until now CI (and any other external
consumer) needed a hand-maintained lookup table to derive the full
patch version + python-build release date from the short
SERIOUS_PYTHON_VERSION. Last CI run failed exactly because the new
SERIOUS_PYTHON_FULL_VERSION / SERIOUS_PYTHON_BUILD_DATE env vars were
unset in CI, the plugin scripts fell back to their 3.14.6/20260611
defaults, and Linux's ninja then complained that the 3.12 tarball was
missing libpython3.14.so.1.0.

New `version` subcommand emits the registry as either a human-readable
summary or `--json` (machine-readable). Self-version comes from
pubspec.yaml looked up via `package_config` (no Dart constant to keep
in sync). Registry rows are sorted descending in the text output to
match `flet --version` ordering.

`_pythonReleases` and `_PythonRelease` promoted to `pythonReleases` /
`PythonRelease` so the new file can reference them. Internal callers
in `package_command.dart` updated to match.

CI: new composite action `.github/actions/resolve-python-vars` runs
`dart run serious_python:main version --json` + `jq` to write
SERIOUS_PYTHON_FULL_VERSION and SERIOUS_PYTHON_BUILD_DATE into
`$GITHUB_ENV`. Inserted as a `Resolve Python version vars` step right
after `Setup Flutter` in all 15 test jobs (publish job left untouched).
Future Python registry bumps need no CI changes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: FeodorFitsner

.github/actions/resolve-python-vars/action.yml

@@ -0,0 +1,38 @@
+name: Resolve serious_python Python-version vars
+description: |
+  Derive `SERIOUS_PYTHON_FULL_VERSION` and `SERIOUS_PYTHON_BUILD_DATE` for
+  the current `SERIOUS_PYTHON_VERSION` from `dart run serious_python:main
+  version --json` and export them to `$GITHUB_ENV` so subsequent steps —
+  including the platform plugin build scripts (Android `build.gradle`,
+  Darwin `prepare_{ios,macos}.sh`, Linux/Windows `CMakeLists.txt`) — pick
+  up the registry-correct values without having to hand-maintain a lookup
+  table in the workflow.
+
+  Requires Flutter to be on PATH and `SERIOUS_PYTHON_VERSION` to be set in
+  env (typically by the caller's `env:` block, keyed off
+  `matrix.python_version`).
+
+runs:
+  using: composite
+  steps:
+    - name: Resolve full version + python-build date
+      shell: bash
+      working-directory: src/serious_python
+      run: |
+        set -euo pipefail
+        if [[ -z "${SERIOUS_PYTHON_VERSION:-}" ]]; then
+          echo "::error::SERIOUS_PYTHON_VERSION is not set in env."
+          exit 1
+        fi
+        flutter pub get >/dev/null
+        json=$(dart run serious_python:main version --json)
+        full=$(echo "$json" | jq -r ".python_releases.\"${SERIOUS_PYTHON_VERSION}\".standalone_version")
+        date=$(echo "$json" | jq -r ".python_releases.\"${SERIOUS_PYTHON_VERSION}\".python_build_release_date")
+        if [[ -z "$full" || "$full" == "null" || -z "$date" || "$date" == "null" ]]; then
+          echo "::error::serious_python:main version --json did not return values for SERIOUS_PYTHON_VERSION=${SERIOUS_PYTHON_VERSION}"
+          echo "$json"
+          exit 1
+        fi
+        echo "SERIOUS_PYTHON_FULL_VERSION=$full" >> "$GITHUB_ENV"
+        echo "SERIOUS_PYTHON_BUILD_DATE=$date" >> "$GITHUB_ENV"
+        echo "Resolved Python $SERIOUS_PYTHON_VERSION: full=$full, python-build date=$date"

.github/workflows/ci.yml

@@ -60,6 +60,9 @@ jobs:
           path: '.fvmrc'
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Run tests
         working-directory: "src/serious_python/example/flet_example"
         run: |
@@ -86,6 +89,9 @@ jobs:
           path: '.fvmrc'
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Setup iOS Simulator
         id: simulator
         uses: futureware-tech/simulator-action@v4
@@ -123,6 +129,9 @@ jobs:
           path: '.fvmrc'
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Enable KVM
         run: |
           echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' | sudo tee /etc/udev/rules.d/99-kvm4all.rules
@@ -183,6 +192,9 @@ jobs:
           path: '.fvmrc'
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Run tests
         working-directory:  "src/serious_python/example/flet_example"
         run: |
@@ -227,6 +239,9 @@ jobs:
           channel: ${{ matrix.arch == 'arm64' && 'master' || 'stable' }}  # https://github.com/subosito/flutter-action/issues/345#issuecomment-2657332687
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Install dependencies
         run: |
           sudo apt-get update --allow-releaseinfo-change
@@ -285,6 +300,9 @@ jobs:
           path: '.fvmrc'
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Cache flet downloads
         uses: actions/cache@v4
         with:
@@ -324,6 +342,9 @@ jobs:
           path: '.fvmrc'
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Cache flet downloads
         uses: actions/cache@v4
         with:
@@ -373,6 +394,9 @@ jobs:
           path: '.fvmrc'
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Cache flet downloads
         uses: actions/cache@v4
         with:
@@ -446,6 +470,9 @@ jobs:
           path: '.fvmrc'
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Cache flet downloads
         uses: actions/cache@v4
         with:
@@ -505,6 +532,9 @@ jobs:
           channel: ${{ matrix.arch == 'arm64' && 'master' || 'stable' }}
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Cache flet downloads
         uses: actions/cache@v4
         with:
@@ -576,6 +606,9 @@ jobs:
           path: '.fvmrc'
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Package + run integration test
         working-directory: "src/serious_python/example/bridge_example"
         run: |
@@ -603,6 +636,9 @@ jobs:
           path: '.fvmrc'
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       # Replaced by the unified ~/.flet/cache step lifted to every job; left
       # the comment for git-blame breadcrumb. The bridge_example matrix is
       # gated off pending re-enable; once flipped back on, add the cache
@@ -655,6 +691,9 @@ jobs:
           path: '.fvmrc'
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Enable KVM
         run: |
           echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' | sudo tee /etc/udev/rules.d/99-kvm4all.rules
@@ -733,6 +772,9 @@ jobs:
           path: '.fvmrc'
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Package + run integration test
         working-directory: "src/serious_python/example/bridge_example"
         shell: bash
@@ -798,6 +840,9 @@ jobs:
           channel: ${{ matrix.arch == 'arm64' && 'master' || 'stable' }}
           cache: true
 
+      - name: Resolve Python version vars
+        uses: ./.github/actions/resolve-python-vars
+
       - name: Install Linux desktop build deps
         run: |
           sudo apt-get update --allow-releaseinfo-change

src/serious_python/bin/main.dart

@@ -1,11 +1,13 @@
 import 'package:args/command_runner.dart';
 
 import 'package_command.dart';
+import 'version_command.dart';
 
 void main(List<String> arguments) async {
   var runner = CommandRunner("dart run serious_python:main",
       "A tool for packaging Python apps to work with serious_python package.")
-    ..addCommand(PackageCommand());
+    ..addCommand(PackageCommand())
+    ..addCommand(VersionCommand());
 
   await runner.run(arguments);
 }

src/serious_python/bin/package_command.dart

@@ -32,8 +32,8 @@ const pyodideVersionEnvironmentVariable = "SERIOUS_PYTHON_PYODIDE_VERSION";
 
 const defaultPythonVersion = "3.14";
 
-class _PythonRelease {
-  const _PythonRelease({
+class PythonRelease {
+  const PythonRelease({
     required this.standaloneVersion,
     required this.standaloneReleaseDate,
     required this.pythonBuildReleaseDate,
@@ -61,24 +61,24 @@ class _PythonRelease {
 
 // Source of truth for the Python <-> CPython standalone <-> Pyodide mapping.
 // Mirror any change here in flet-cli's python_versions.py.
-const _pythonReleases = <String, _PythonRelease>{
-  "3.12": _PythonRelease(
+const pythonReleases = <String, PythonRelease>{
+  "3.12": PythonRelease(
     standaloneVersion: "3.12.13",
     standaloneReleaseDate: "20260610",
     pythonBuildReleaseDate: "20260611",
     pyodideVersion: "0.27.7",
     pyodidePlatformTag: "pyodide-2024.0-wasm32",
     prerelease: false,
   ),
-  "3.13": _PythonRelease(
+  "3.13": PythonRelease(
     standaloneVersion: "3.13.14",
     standaloneReleaseDate: "20260610",
     pythonBuildReleaseDate: "20260611",
     pyodideVersion: "0.29.4",
     pyodidePlatformTag: "pyemscripten-2025.0-wasm32",
     prerelease: false,
   ),
-  "3.14": _PythonRelease(
+  "3.14": PythonRelease(
     standaloneVersion: "3.14.6",
     standaloneReleaseDate: "20260610",
     pythonBuildReleaseDate: "20260611",
@@ -91,7 +91,7 @@ const _pythonReleases = <String, _PythonRelease>{
   // `requires-python = "==3.15.*"` on the Flet CLI side) without becoming
   // the default or matching open-ended `requires-python` specifiers.
   //
-  // "3.15": _PythonRelease(
+  // "3.15": PythonRelease(
   //   standaloneVersion: "3.15.0",
   //   standaloneReleaseDate: "...",
   //   pythonBuildReleaseDate: "...",
@@ -125,7 +125,7 @@ const platforms = {
   },
   "Emscripten": {
     // The actual wheel platform tag is resolved per Python release from
-    // `_pythonReleases[...].pyodidePlatformTag` (see sitecustomize wiring
+    // `pythonReleases[...].pyodidePlatformTag` (see sitecustomize wiring
     // below) since it changes with each Pyodide ABI bump.
     "": {"tag": "", "mac_ver": ""}
   },
@@ -168,7 +168,7 @@ class PackageCommand extends Command {
   Directory? _buildDir;
   Directory? _pythonDir;
   late String _pythonShortVersion;
-  late _PythonRelease _release;
+  late PythonRelease _release;
 
   String get _pyodideRootUrl =>
       "https://cdn.jsdelivr.net/pyodide/v${_release.pyodideVersion}/full";
@@ -200,7 +200,7 @@ class PackageCommand extends Command {
         mandatory: true,
         help: "Install dependencies for specific platform, e.g. 'Android'.");
     argParser.addOption('python-version',
-        allowed: _pythonReleases.keys.toList(),
+        allowed: pythonReleases.keys.toList(),
         help: "Short Python version to bundle (e.g. 3.13). Defaults to "
             "\$$pythonVersionEnvironmentVariable env var or "
             "'$defaultPythonVersion'.");
@@ -280,13 +280,13 @@ class PackageCommand extends Command {
       _pythonShortVersion = argResults?['python-version'] ??
           Platform.environment[pythonVersionEnvironmentVariable] ??
           defaultPythonVersion;
-      final baseRelease = _pythonReleases[_pythonShortVersion];
+      final baseRelease = pythonReleases[_pythonShortVersion];
       if (baseRelease == null) {
         stderr.writeln(
-            "Unknown Python version: $_pythonShortVersion. Supported: ${_pythonReleases.keys.join(", ")}");
+            "Unknown Python version: $_pythonShortVersion. Supported: ${pythonReleases.keys.join(", ")}");
         exit(2);
       }
-      _release = _PythonRelease(
+      _release = PythonRelease(
         standaloneVersion:
             Platform.environment[pythonFullVersionEnvironmentVariable] ??
                 baseRelease.standaloneVersion,

src/serious_python/bin/version_command.dart

@@ -0,0 +1,89 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:args/command_runner.dart';
+import 'package:package_config/package_config.dart';
+
+import 'package_command.dart';
+
+/// `version` subcommand: prints the serious_python package version, the
+/// default Python version, and the supported-Python matrix sourced from
+/// [pythonReleases] in `package_command.dart`. With `--json`, emits a
+/// machine-readable document for CI / tooling consumption.
+class VersionCommand extends Command {
+  @override
+  final name = "version";
+
+  @override
+  final description =
+      "Print serious_python version and the supported Python matrix.";
+
+  VersionCommand() {
+    argParser.addFlag(
+      "json",
+      help: "Emit machine-readable JSON instead of the human-readable summary.",
+      negatable: false,
+    );
+  }
+
+  @override
+  Future<void> run() async {
+    final version = await _readSeriousPythonVersion() ?? "unknown";
+    final jsonMode = argResults?["json"] ?? false;
+
+    if (jsonMode) {
+      final doc = <String, dynamic>{
+        "serious_python_version": version,
+        "default_python_version": defaultPythonVersion,
+        "python_releases": <String, dynamic>{
+          for (final entry in pythonReleases.entries)
+            entry.key: {
+              "standalone_version": entry.value.standaloneVersion,
+              "standalone_release_date": entry.value.standaloneReleaseDate,
+              "python_build_release_date": entry.value.pythonBuildReleaseDate,
+              "pyodide_version": entry.value.pyodideVersion,
+              "pyodide_platform_tag": entry.value.pyodidePlatformTag,
+              "prerelease": entry.value.prerelease,
+            },
+        },
+      };
+      stdout.writeln(const JsonEncoder.withIndent("  ").convert(doc));
+      return;
+    }
+
+    stdout.writeln("serious_python $version");
+    stdout.writeln("Default Python: $defaultPythonVersion");
+    stdout.writeln("Supported Python versions:");
+    // Sort descending so the default + newest stable is on top, matching the
+    // ordering convention used by `flet --version`.
+    final keys = pythonReleases.keys.toList()
+      ..sort((a, b) => b.compareTo(a));
+    for (final k in keys) {
+      final r = pythonReleases[k]!;
+      final markers = <String>[];
+      if (k == defaultPythonVersion) markers.add("default");
+      if (r.prerelease) markers.add("pre-release");
+      final markerSuffix = markers.isEmpty ? "" : " (${markers.join(", ")})";
+      stdout.writeln(
+          "  $k$markerSuffix: CPython ${r.standaloneVersion} / Pyodide ${r.pyodideVersion}");
+    }
+  }
+
+  /// Read this package's `version:` from its `pubspec.yaml`, found via the
+  /// caller's `package_config.json`. Returns `null` if the package_config
+  /// can't be located (e.g. invoked from a compiled snapshot outside any
+  /// pub workspace).
+  Future<String?> _readSeriousPythonVersion() async {
+    final config = await findPackageConfig(Directory.current);
+    final pkg = config?["serious_python"];
+    if (pkg == null) return null;
+    final pubspec = File.fromUri(pkg.root.resolve("pubspec.yaml"));
+    if (!pubspec.existsSync()) return null;
+    final versionPattern = RegExp(r'^version:\s*(\S+)\s*$');
+    for (final line in pubspec.readAsLinesSync()) {
+      final match = versionPattern.firstMatch(line);
+      if (match != null) return match.group(1);
+    }
+    return null;
+  }
+}

src/serious_python/pubspec.yaml

@@ -53,6 +53,7 @@ dependencies:
   crypto: ^3.0.5
   glob: ^2.1.3
   ffi: ^2.1.2
+  package_config: ^2.1.0
 
 dev_dependencies:
   flutter_test: