check failures fix

Bumps [eslint-plugin-jest](https://github.com/jest-community/eslint-plugin-jest) from 27.9.0 to 28.11.0.
- [Release notes](https://github.com/jest-community/eslint-plugin-jest/releases)
- [Changelog](https://github.com/jest-community/eslint-plugin-jest/blob/main/CHANGELOG.md)
- [Commits](https://github.com/jest-community/eslint-plugin-jest/compare/v27.9.0...v28.11.0)

---
updated-dependencies:
- dependency-name: eslint-plugin-jest
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/test-pypy.yml

@@ -69,6 +69,59 @@ jobs:
           ${EXECUTABLE} --version
         shell: bash
 
+  check-non-eol:
+    name: Check non-eol ${{ matrix.pypy }} on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - macos-13
+          - macos-14
+          - macos-15
+          - windows-2019
+          - windows-2022
+          - windows-2025
+          - ubuntu-22.04
+          - ubuntu-24.04
+          - ubuntu-22.04-arm
+          - ubuntu-24.04-arm
+        pypy: ['pypy-2.7', 'pypy-3.10']
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: setup-python ${{ matrix.pypy }}
+        id: setup-python
+        uses: ./
+        with:
+          python-version: ${{ matrix.pypy }}
+
+      - name: Check python-path
+        run: ./__tests__/check-python-path.sh '${{ steps.setup-python.outputs.python-path }}'
+        shell: bash
+
+      - name: PyPy and Python version
+        run: python --version
+
+      - name: Run simple code
+        run: python -c 'import math; print(math.factorial(5))'
+
+      - name: Assert PyPy is running
+        run: |
+          import platform
+          assert platform.python_implementation().lower() == "pypy"
+        shell: python
+
+      - name: Assert expected binaries (or symlinks) are present
+        run: |
+          EXECUTABLE=${{ matrix.pypy }}
+          EXECUTABLE=${EXECUTABLE/pypy-/pypy}  # remove the first '-' in "pypy-X.Y" -> "pypyX.Y" to match executable name
+          EXECUTABLE=${EXECUTABLE%%-*}  # remove any -* suffixe
+          ${EXECUTABLE} --version
+        shell: bash
+
   setup-pypy-noenv:
     name: Setup PyPy ${{ matrix.pypy }} ${{ matrix.os }} (noenv)
     runs-on: ${{ matrix.os }}

README.md

@@ -45,6 +45,16 @@ steps:
 - run: python my_script.py
 ```
 
+**Free threaded Python**
+```yaml
+steps:
+- uses: actions/checkout@v4
+- uses: actions/setup-python@v5
+  with:
+    python-version: '3.13t'
+- run: python my_script.py
+```
+
 The `python-version` input is optional. If not supplied, the action will try to resolve the version from the default `.python-version` file. If the `.python-version` file doesn't exist Python or PyPy version from the PATH will be used. The default version of Python or PyPy in PATH varies between runners and can be changed unexpectedly so we recommend always setting Python version explicitly using the `python-version` or `python-version-file` inputs.
 
 The action will first check the local [tool cache](docs/advanced-usage.md#hosted-tool-cache) for a [semver](https://github.com/npm/node-semver#versions) match. If unable to find a specific version in the tool cache, the action will attempt to download a version of Python from [GitHub Releases](https://github.com/actions/python-versions/releases) and for PyPy from the official [PyPy's dist](https://downloads.python.org/pypy/).

__tests__/find-python.test.ts

@@ -0,0 +1,43 @@
+import {desugarVersion, pythonVersionToSemantic} from '../src/find-python';
+
+describe('desugarVersion', () => {
+  it.each([
+    ['3.13', {version: '3.13', freethreaded: false}],
+    ['3.13t', {version: '3.13', freethreaded: true}],
+    ['3.13.1', {version: '3.13.1', freethreaded: false}],
+    ['3.13.1t', {version: '3.13.1', freethreaded: true}],
+    ['3.14-dev', {version: '~3.14.0-0', freethreaded: false}],
+    ['3.14t-dev', {version: '~3.14.0-0', freethreaded: true}]
+  ])('%s -> %s', (input, expected) => {
+    expect(desugarVersion(input)).toEqual(expected);
+  });
+});
+
+// Test the combined desugarVersion and pythonVersionToSemantic functions
+describe('pythonVersions', () => {
+  it.each([
+    ['3.13', {version: '3.13', freethreaded: false}],
+    ['3.13t', {version: '3.13', freethreaded: true}],
+    ['3.13.1', {version: '3.13.1', freethreaded: false}],
+    ['3.13.1t', {version: '3.13.1', freethreaded: true}],
+    ['3.14-dev', {version: '~3.14.0-0', freethreaded: false}],
+    ['3.14t-dev', {version: '~3.14.0-0', freethreaded: true}]
+  ])('%s -> %s', (input, expected) => {
+    const {version, freethreaded} = desugarVersion(input);
+    const semanticVersionSpec = pythonVersionToSemantic(version, false);
+    expect({version: semanticVersionSpec, freethreaded}).toEqual(expected);
+  });
+
+  it.each([
+    ['3.13', {version: '~3.13.0-0', freethreaded: false}],
+    ['3.13t', {version: '~3.13.0-0', freethreaded: true}],
+    ['3.13.1', {version: '3.13.1', freethreaded: false}],
+    ['3.13.1t', {version: '3.13.1', freethreaded: true}],
+    ['3.14-dev', {version: '~3.14.0-0', freethreaded: false}],
+    ['3.14t-dev', {version: '~3.14.0-0', freethreaded: true}]
+  ])('%s (allowPreReleases=true) -> %s', (input, expected) => {
+    const {version, freethreaded} = desugarVersion(input);
+    const semanticVersionSpec = pythonVersionToSemantic(version, true);
+    expect({version: semanticVersionSpec, freethreaded}).toEqual(expected);
+  });
+});

__tests__/finder.test.ts

@@ -56,7 +56,7 @@ describe('Finder tests', () => {
     await io.mkdirP(pythonDir);
     fs.writeFileSync(`${pythonDir}.complete`, 'hello');
     // This will throw if it doesn't find it in the cache and in the manifest (because no such version exists)
-    await finder.useCpythonVersion('3.x', 'x64', true, false, false);
+    await finder.useCpythonVersion('3.x', 'x64', true, false, false, false);
     expect(spyCoreAddPath).toHaveBeenCalled();
     expect(spyCoreExportVariable).toHaveBeenCalledWith(
       'pythonLocation',
@@ -73,7 +73,7 @@ describe('Finder tests', () => {
     await io.mkdirP(pythonDir);
     fs.writeFileSync(`${pythonDir}.complete`, 'hello');
     // This will throw if it doesn't find it in the cache and in the manifest (because no such version exists)
-    await finder.useCpythonVersion('3.x', 'x64', false, false, false);
+    await finder.useCpythonVersion('3.x', 'x64', false, false, false, false);
     expect(spyCoreAddPath).not.toHaveBeenCalled();
     expect(spyCoreExportVariable).not.toHaveBeenCalled();
   });
@@ -96,7 +96,7 @@ describe('Finder tests', () => {
     });
     // This will throw if it doesn't find it in the cache and in the manifest (because no such version exists)
     await expect(
-      finder.useCpythonVersion('1.2.3', 'x64', true, false, false)
+      finder.useCpythonVersion('1.2.3', 'x64', true, false, false, false)
     ).resolves.toEqual({
       impl: 'CPython',
       version: '1.2.3'
@@ -135,7 +135,14 @@ describe('Finder tests', () => {
     });
     // This will throw if it doesn't find it in the manifest (because no such version exists)
     await expect(
-      finder.useCpythonVersion('1.2.4-beta.2', 'x64', false, false, false)
+      finder.useCpythonVersion(
+        '1.2.4-beta.2',
+        'x64',
+        false,
+        false,
+        false,
+        false
+      )
     ).resolves.toEqual({
       impl: 'CPython',
       version: '1.2.4-beta.2'
@@ -186,7 +193,7 @@ describe('Finder tests', () => {
 
     fs.writeFileSync(`${pythonDir}.complete`, 'hello');
     // This will throw if it doesn't find it in the cache and in the manifest (because no such version exists)
-    await finder.useCpythonVersion('1.2', 'x64', true, true, false);
+    await finder.useCpythonVersion('1.2', 'x64', true, true, false, false);
 
     expect(infoSpy).toHaveBeenCalledWith("Resolved as '1.2.3'");
     expect(infoSpy).toHaveBeenCalledWith(
@@ -197,7 +204,14 @@ describe('Finder tests', () => {
     );
     expect(installSpy).toHaveBeenCalled();
     expect(addPathSpy).toHaveBeenCalledWith(expPath);
-    await finder.useCpythonVersion('1.2.4-beta.2', 'x64', false, true, false);
+    await finder.useCpythonVersion(
+      '1.2.4-beta.2',
+      'x64',
+      false,
+      true,
+      false,
+      false
+    );
     expect(spyCoreAddPath).toHaveBeenCalled();
     expect(spyCoreExportVariable).toHaveBeenCalledWith(
       'pythonLocation',
@@ -224,7 +238,7 @@ describe('Finder tests', () => {
     });
     // This will throw if it doesn't find it in the cache and in the manifest (because no such version exists)
     await expect(
-      finder.useCpythonVersion('1.2', 'x64', false, false, false)
+      finder.useCpythonVersion('1.2', 'x64', false, false, false, false)
     ).resolves.toEqual({
       impl: 'CPython',
       version: '1.2.3'
@@ -251,17 +265,17 @@ describe('Finder tests', () => {
     });
     // This will throw if it doesn't find it in the cache and in the manifest (because no such version exists)
     await expect(
-      finder.useCpythonVersion('1.1', 'x64', false, false, false)
+      finder.useCpythonVersion('1.1', 'x64', false, false, false, false)
     ).rejects.toThrow();
     await expect(
-      finder.useCpythonVersion('1.1', 'x64', false, false, true)
+      finder.useCpythonVersion('1.1', 'x64', false, false, true, false)
     ).resolves.toEqual({
       impl: 'CPython',
       version: '1.1.0-beta.2'
     });
     // Check 1.1.0 version specifier does not fallback to '1.1.0-beta.2'
     await expect(
-      finder.useCpythonVersion('1.1.0', 'x64', false, false, true)
+      finder.useCpythonVersion('1.1.0', 'x64', false, false, true, false)
     ).rejects.toThrow();
   });
 
@@ -269,7 +283,14 @@ describe('Finder tests', () => {
     // This will throw if it doesn't find it in the cache and in the manifest (because no such version exists)
     let thrown = false;
     try {
-      await finder.useCpythonVersion('3.300000', 'x64', true, false, false);
+      await finder.useCpythonVersion(
+        '3.300000',
+        'x64',
+        true,
+        false,
+        false,
+        false
+      );
     } catch {
       thrown = true;
     }

action.yml

@@ -26,6 +26,9 @@ inputs:
   allow-prereleases:
     description: "When 'true', a version range passed to 'python-version' input will match prerelease versions if no GA versions are found. Only 'x.y' version range is supported for CPython."
     default: false
+  freethreaded:
+    description: "When 'true', use the freethreaded version of Python."
+    default: false
 outputs:
   python-version:
     description: "The installed Python or PyPy version. Useful when given a version range as input."

docs/advanced-usage.md

@@ -77,6 +77,31 @@ steps:
 - run: python my_script.py
 ```
 
+You can specify the [free threading](https://docs.python.org/3/howto/free-threading-python.html) version of Python by setting the `freethreaded` input to `true` or by using the special **t** suffix in some cases.
+You can use the **t** suffix when specifying the major and minor version (e.g., `3.13t`), with a patch version (e.g., `3.13.1t`), or with the **x.y-dev syntax** (e.g., `3.14t-dev`).
+Free threaded Python is only available starting with the 3.13 release.
+
+```yaml
+steps:
+- uses: actions/checkout@v4
+- uses: actions/setup-python@v5
+  with:
+    python-version: '3.13t'
+- run: python my_script.py
+```
+
+Note that the **t** suffix is not `semver` syntax. If you wish to specify a range, you must use the `freethreaded` input instead of the `t` suffix.
+
+```yaml
+steps:
+- uses: actions/checkout@v4
+- uses: actions/setup-python@v5
+  with:
+    python-version: '>=3.13'
+    freethreaded: true
+- run: python my_script.py
+```
+
 You can also use several types of ranges that are specified in [semver](https://github.com/npm/node-semver#ranges), for instance:
 
 - **[ranges](https://github.com/npm/node-semver#ranges)** to download and set up the latest available version of Python satisfying a range:

package-lock.json

@@ -23,12 +23,12 @@
         "@types/jest": "^29.5.12",
         "@types/node": "^20.11.25",
         "@types/semver": "^7.5.8",
-        "@typescript-eslint/eslint-plugin": "^5.54.0",
-        "@typescript-eslint/parser": "^5.54.0",
-        "@vercel/ncc": "^0.38.0",
+        "@typescript-eslint/eslint-plugin": "^8.26.1",
+        "@typescript-eslint/parser": "^8.26.1",
+        "@vercel/ncc": "^0.38.3",
         "eslint": "^8.57.0",
         "eslint-config-prettier": "^8.6.0",
-        "eslint-plugin-jest": "^27.9.0",
+        "eslint-plugin-jest": "^28.11.0",
         "eslint-plugin-node": "^11.1.0",
         "jest": "^29.7.0",
         "jest-circus": "^29.7.0",
@@ -1745,12 +1745,6 @@
         "pretty-format": "^29.0.0"
       }
     },
-    "node_modules/@types/json-schema": {
-      "version": "7.0.15",
-      "resolved": "https://registry.npmjs.org/@types/json-schema/-/json-schema-7.0.15.tgz",
-      "integrity": "sha512-5+fP8P8MFNC+AyZCDxrB2pkZFPGzqQWUzpSeuuVLvm8VMcorNYavBqoFcxK8bQz4Qsbn4oUEEem4wDLfcysGHA==",
-      "dev": true
-    },
     "node_modules/@types/node": {
       "version": "20.11.25",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-20.11.25.tgz",
@@ -1817,77 +1811,72 @@
       "dev": true
     },
     "node_modules/@typescript-eslint/eslint-plugin": {
-      "version": "5.62.0",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-5.62.0.tgz",
-      "integrity": "sha512-TiZzBSJja/LbhNPvk6yc0JrX9XqhQ0hdh6M2svYfsHGejaKFIAGd9MQ+ERIMzLGlN/kZoYIgdxFV0PuljTKXag==",
+      "version": "8.26.1",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-8.26.1.tgz",
+      "integrity": "sha512-2X3mwqsj9Bd3Ciz508ZUtoQQYpOhU/kWoUqIf49H8Z0+Vbh6UF/y0OEYp0Q0axOGzaBGs7QxRwq0knSQ8khQNA==",
       "dev": true,
+      "license": "MIT",
       "dependencies": {
-        "@eslint-community/regexpp": "^4.4.0",
-        "@typescript-eslint/scope-manager": "5.62.0",
-        "@typescript-eslint/type-utils": "5.62.0",
-        "@typescript-eslint/utils": "5.62.0",
-        "debug": "^4.3.4",
+        "@eslint-community/regexpp": "^4.10.0",
+        "@typescript-eslint/scope-manager": "8.26.1",
+        "@typescript-eslint/type-utils": "8.26.1",
+        "@typescript-eslint/utils": "8.26.1",
+        "@typescript-eslint/visitor-keys": "8.26.1",
         "graphemer": "^1.4.0",
-        "ignore": "^5.2.0",
-        "natural-compare-lite": "^1.4.0",
-        "semver": "^7.3.7",
-        "tsutils": "^3.21.0"
+        "ignore": "^5.3.1",
+        "natural-compare": "^1.4.0",
+        "ts-api-utils": "^2.0.1"
       },
       "engines": {
-        "node": "^12.22.0 || ^14.17.0 || >=16.0.0"
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
       },
       "funding": {
         "type": "opencollective",
         "url": "https://opencollective.com/typescript-eslint"
       },
       "peerDependencies": {
-        "@typescript-eslint/parser": "^5.0.0",
-        "eslint": "^6.0.0 || ^7.0.0 || ^8.0.0"
-      },
-      "peerDependenciesMeta": {
-        "typescript": {
-          "optional": true
-        }
+        "@typescript-eslint/parser": "^8.0.0 || ^8.0.0-alpha.0",
+        "eslint": "^8.57.0 || ^9.0.0",
+        "typescript": ">=4.8.4 <5.9.0"
       }
     },
     "node_modules/@typescript-eslint/parser": {
-      "version": "5.62.0",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/parser/-/parser-5.62.0.tgz",
-      "integrity": "sha512-VlJEV0fOQ7BExOsHYAGrgbEiZoi8D+Bl2+f6V2RrXerRSylnp+ZBHmPvaIa8cz0Ajx7WO7Z5RqfgYg7ED1nRhA==",
+      "version": "8.26.1",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/parser/-/parser-8.26.1.tgz",
+      "integrity": "sha512-w6HZUV4NWxqd8BdeFf81t07d7/YV9s7TCWrQQbG5uhuvGUAW+fq1usZ1Hmz9UPNLniFnD8GLSsDpjP0hm1S4lQ==",
       "dev": true,
+      "license": "MIT",
       "dependencies": {
-        "@typescript-eslint/scope-manager": "5.62.0",
-        "@typescript-eslint/types": "5.62.0",
-        "@typescript-eslint/typescript-estree": "5.62.0",
+        "@typescript-eslint/scope-manager": "8.26.1",
+        "@typescript-eslint/types": "8.26.1",
+        "@typescript-eslint/typescript-estree": "8.26.1",
+        "@typescript-eslint/visitor-keys": "8.26.1",
         "debug": "^4.3.4"
       },
       "engines": {
-        "node": "^12.22.0 || ^14.17.0 || >=16.0.0"
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
       },
       "funding": {
         "type": "opencollective",
         "url": "https://opencollective.com/typescript-eslint"
       },
       "peerDependencies": {
-        "eslint": "^6.0.0 || ^7.0.0 || ^8.0.0"
-      },
-      "peerDependenciesMeta": {
-        "typescript": {
-          "optional": true
-        }
+        "eslint": "^8.57.0 || ^9.0.0",
+        "typescript": ">=4.8.4 <5.9.0"
       }
     },
     "node_modules/@typescript-eslint/scope-manager": {
-      "version": "5.62.0",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/scope-manager/-/scope-manager-5.62.0.tgz",
-      "integrity": "sha512-VXuvVvZeQCQb5Zgf4HAxc04q5j+WrNAtNh9OwCsCgpKqESMTu3tF/jhZ3xG6T4NZwWl65Bg8KuS2uEvhSfLl0w==",
+      "version": "8.26.1",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/scope-manager/-/scope-manager-8.26.1.tgz",
+      "integrity": "sha512-6EIvbE5cNER8sqBu6V7+KeMZIC1664d2Yjt+B9EWUXrsyWpxx4lEZrmvxgSKRC6gX+efDL/UY9OpPZ267io3mg==",
       "dev": true,
+      "license": "MIT",
       "dependencies": {
-        "@typescript-eslint/types": "5.62.0",
-        "@typescript-eslint/visitor-keys": "5.62.0"
+        "@typescript-eslint/types": "8.26.1",
+        "@typescript-eslint/visitor-keys": "8.26.1"
       },
       "engines": {
-        "node": "^12.22.0 || ^14.17.0 || >=16.0.0"
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
       },
       "funding": {
         "type": "opencollective",
@@ -1895,39 +1884,37 @@
       }
     },
     "node_modules/@typescript-eslint/type-utils": {
-      "version": "5.62.0",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/type-utils/-/type-utils-5.62.0.tgz",
-      "integrity": "sha512-xsSQreu+VnfbqQpW5vnCJdq1Z3Q0U31qiWmRhr98ONQmcp/yhiPJFPq8MXiJVLiksmOKSjIldZzkebzHuCGzew==",
+      "version": "8.26.1",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/type-utils/-/type-utils-8.26.1.tgz",
+      "integrity": "sha512-Kcj/TagJLwoY/5w9JGEFV0dclQdyqw9+VMndxOJKtoFSjfZhLXhYjzsQEeyza03rwHx2vFEGvrJWJBXKleRvZg==",
       "dev": true,
+      "license": "MIT",
       "dependencies": {
-        "@typescript-eslint/typescript-estree": "5.62.0",
-        "@typescript-eslint/utils": "5.62.0",
+        "@typescript-eslint/typescript-estree": "8.26.1",
+        "@typescript-eslint/utils": "8.26.1",
         "debug": "^4.3.4",
-        "tsutils": "^3.21.0"
+        "ts-api-utils": "^2.0.1"
       },
       "engines": {
-        "node": "^12.22.0 || ^14.17.0 || >=16.0.0"
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
       },
       "funding": {
         "type": "opencollective",
         "url": "https://opencollective.com/typescript-eslint"
       },
       "peerDependencies": {
-        "eslint": "*"
-      },
-      "peerDependenciesMeta": {
-        "typescript": {
-          "optional": true
-        }
+        "eslint": "^8.57.0 || ^9.0.0",
+        "typescript": ">=4.8.4 <5.9.0"
       }
     },
     "node_modules/@typescript-eslint/types": {
-      "version": "5.62.0",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/types/-/types-5.62.0.tgz",
-      "integrity": "sha512-87NVngcbVXUahrRTqIK27gD2t5Cu1yuCXxbLcFtCzZGlfyVWWh8mLHkoxzjsB6DDNnvdL+fW8MiwPEJyGJQDgQ==",
+      "version": "8.26.1",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/types/-/types-8.26.1.tgz",
+      "integrity": "sha512-n4THUQW27VmQMx+3P+B0Yptl7ydfceUj4ON/AQILAASwgYdZ/2dhfymRMh5egRUrvK5lSmaOm77Ry+lmXPOgBQ==",
       "dev": true,
+      "license": "MIT",
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-    },
-    "node_modules/tsutils/node_modules/tslib": {
-      "version": "1.14.1",
-      "resolved": "https://registry.npmjs.org/tslib/-/tslib-1.14.1.tgz",
-      "integrity": "sha512-Xni35NKzjgMrwevysHTCArtLDpPvye8zV/0E4EyYn43P7/7qvQwPh9BGkHewbMulVntbigmcT7rdX3BNo9wRJg==",
-      "dev": true
-    },
     "node_modules/tunnel": {
       "version": "0.0.6",
       "resolved": "https://registry.npmjs.org/tunnel/-/tunnel-0.0.6.tgz",

package.json

@@ -39,12 +39,12 @@
     "@types/jest": "^29.5.12",
     "@types/node": "^20.11.25",
     "@types/semver": "^7.5.8",
-    "@typescript-eslint/eslint-plugin": "^5.54.0",
-    "@typescript-eslint/parser": "^5.54.0",
-    "@vercel/ncc": "^0.38.0",
+    "@typescript-eslint/eslint-plugin": "^8.26.1",
+    "@typescript-eslint/parser": "^8.26.1",
+    "@vercel/ncc": "^0.38.3",
     "eslint": "^8.57.0",
     "eslint-config-prettier": "^8.6.0",
-    "eslint-plugin-jest": "^27.9.0",
+    "eslint-plugin-jest": "^28.11.0",
     "eslint-plugin-node": "^11.1.0",
     "jest": "^29.7.0",
     "jest-circus": "^29.7.0",

src/find-python.ts

@@ -35,16 +35,28 @@ export async function useCpythonVersion(
   architecture: string,
   updateEnvironment: boolean,
   checkLatest: boolean,
-  allowPreReleases: boolean
+  allowPreReleases: boolean,
+  freethreaded: boolean
 ): Promise<InstalledVersion> {
   let manifest: tc.IToolRelease[] | null = null;
-  const desugaredVersionSpec = desugarDevVersion(version);
+  const {version: desugaredVersionSpec, freethreaded: versionFreethreaded} =
+    desugarVersion(version);
   let semanticVersionSpec = pythonVersionToSemantic(
     desugaredVersionSpec,
     allowPreReleases
   );
+  if (versionFreethreaded) {
+    // Use the freethreaded version if it was specified in the input, e.g., 3.13t
+    freethreaded = true;
+  }
   core.debug(`Semantic version spec of ${version} is ${semanticVersionSpec}`);
 
+  if (freethreaded) {
+    // Free threaded versions use an architecture suffix like `x64-freethreaded`
+    core.debug(`Using freethreaded version of ${semanticVersionSpec}`);
+    architecture += '-freethreaded';
+  }
+
   if (checkLatest) {
     manifest = await installer.getManifest();
     const resolvedVersion = (
@@ -90,16 +102,22 @@ export async function useCpythonVersion(
 
   if (!installDir) {
     const osInfo = await getOSInfo();
-    throw new Error(
-      [
-        `The version '${version}' with architecture '${architecture}' was not found for ${
-          osInfo
-            ? `${osInfo.osName} ${osInfo.osVersion}`
-            : 'this operating system'
-        }.`,
-        `The list of all available versions can be found here: ${installer.MANIFEST_URL}`
-      ].join(os.EOL)
+    const msg = [
+      `The version '${version}' with architecture '${architecture}' was not found for ${
+        osInfo
+          ? `${osInfo.osName} ${osInfo.osVersion}`
+          : 'this operating system'
+      }.`
+    ];
+    if (freethreaded) {
+      msg.push(
+        `Free threaded versions are only available for Python 3.13.0 and later.`
+      );
+    }
+    msg.push(
+      `The list of all available versions can be found here: ${installer.MANIFEST_URL}`
     );
+    throw new Error(msg.join(os.EOL));
   }
 
   const _binDir = binDir(installDir);
@@ -153,10 +171,38 @@ export async function useCpythonVersion(
   }
 
   const installed = versionFromPath(installDir);
-  core.setOutput('python-version', installed);
+  let pythonVersion = installed;
+  if (freethreaded) {
+    // Add the freethreaded suffix to the version (e.g., 3.13.1t)
+    pythonVersion += 't';
+  }
+  core.setOutput('python-version', pythonVersion);
   core.setOutput('python-path', pythonPath);
 
-  return {impl: 'CPython', version: installed};
+  return {impl: 'CPython', version: pythonVersion};
+}
+
+/* Desugar free threaded and dev versions */
+export function desugarVersion(versionSpec: string) {
+  const {version, freethreaded} = desugarFreeThreadedVersion(versionSpec);
+  return {version: desugarDevVersion(version), freethreaded};
+}
+
+/* Identify freethreaded versions like, 3.13t, 3.13.1t, 3.13t-dev.
+ * Returns the version without the `t` and the architectures suffix, if freethreaded */
+function desugarFreeThreadedVersion(versionSpec: string) {
+  const majorMinor = /^(\d+\.\d+(\.\d+)?)(t)$/;
+  if (majorMinor.test(versionSpec)) {
+    return {version: versionSpec.replace(majorMinor, '$1'), freethreaded: true};
+  }
+  const devVersion = /^(\d+\.\d+)(t)(-dev)$/;
+  if (devVersion.test(versionSpec)) {
+    return {
+      version: versionSpec.replace(devVersion, '$1$3'),
+      freethreaded: true
+    };
+  }
+  return {version: versionSpec, freethreaded: false};
 }
 
 /** Convert versions like `3.8-dev` to a version like `~3.8.0-0`. */

src/install-pypy.ts

@@ -8,6 +8,7 @@ import * as exec from '@actions/exec';
 import fs from 'fs';
 
 import {
+  IS_LINUX,
   IS_WINDOWS,
   WINDOWS_PLATFORMS,
   IPyPyManifestRelease,
@@ -246,7 +247,7 @@ export function pypyVersionToSemantic(versionSpec: string) {
 }
 
 export function isArchPresentForWindows(item: any, architecture: string) {
-  architecture = replaceX32toX86(architecture);
+  architecture = pypyArchitecture(architecture);
   return item.files.some(
     (file: any) =>
       WINDOWS_PLATFORMS.includes(file.platform) && file.arch === architecture
@@ -258,13 +259,14 @@ export function isArchPresentForMacOrLinux(
   architecture: string,
   platform: string
 ) {
+  architecture = pypyArchitecture(architecture);
   return item.files.some(
     (file: any) => file.arch === architecture && file.platform === platform
   );
 }
 
 export function findAssetForWindows(releases: any, architecture: string) {
-  architecture = replaceX32toX86(architecture);
+  architecture = pypyArchitecture(architecture);
   return releases.files.find(
     (item: any) =>
       WINDOWS_PLATFORMS.includes(item.platform) && item.arch === architecture
@@ -276,15 +278,18 @@ export function findAssetForMacOrLinux(
   architecture: string,
   platform: string
 ) {
+  architecture = pypyArchitecture(architecture);
   return releases.files.find(
     (item: any) => item.arch === architecture && item.platform === platform
   );
 }
 
-function replaceX32toX86(architecture: string): string {
-  // convert x32 to x86 because os.arch() returns x32 for 32-bit systems but PyPy releases json has x86 arch value.
-  if (architecture === 'x32') {
+function pypyArchitecture(architecture: string): string {
+  if (IS_WINDOWS && architecture === 'x32') {
+    // convert x32 to x86 because os.arch() returns x32 for 32-bit systems but PyPy releases json has x86 arch value.
     architecture = 'x86';
+  } else if (IS_LINUX && architecture === 'arm64') {
+    architecture = 'aarch64';
   }
   return architecture;
 }

src/setup-python.ts

@@ -92,6 +92,7 @@ async function run() {
     const versions = resolveVersionInput();
     const checkLatest = core.getBooleanInput('check-latest');
     const allowPreReleases = core.getBooleanInput('allow-prereleases');
+    const freethreaded = core.getBooleanInput('freethreaded');
 
     if (versions.length) {
       let pythonVersion = '';
@@ -132,7 +133,8 @@ async function run() {
             arch,
             updateEnvironment,
             checkLatest,
-            allowPreReleases
+            allowPreReleases,
+            freethreaded
           );
           pythonVersion = installed.version;
           core.info(`Successfully set up ${installed.impl} (${pythonVersion})`);