feature: add a `python-path` output

Expose a `python-path` output containing the chosen Python executable path.

.github/workflows/test-pypy.yml

@@ -37,10 +37,15 @@ jobs:
         uses: actions/checkout@v2
   
       - 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
   

.github/workflows/test-python.yml

@@ -23,9 +23,14 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v2
 
-    - name: setup default python 
+    - name: setup default python
+      id: setup-python
       uses: ./
 
+    - name: Check python-path
+      run: ./__tests__/check-python-path.sh '${{ steps.setup-python.outputs.python-path }}'
+      shell: bash
+
     - name: Validate version
       run: python --version
 
@@ -45,10 +50,15 @@ jobs:
       uses: actions/checkout@v2
 
     - name: setup-python ${{ matrix.python }}
+      id: setup-python
       uses: ./
       with:
         python-version: ${{ matrix.python }}
 
+    - name: Check python-path
+      run: ./__tests__/check-python-path.sh '${{ steps.setup-python.outputs.python-path }}'
+      shell: bash
+
     - name: Validate version
       run: |
         $pythonVersion = (python --version)
@@ -74,10 +84,15 @@ jobs:
       uses: actions/checkout@v2
 
     - name: setup-python 3.9.0-beta.4
+      id: setup-python
       uses: ./
       with:
         python-version: '3.9.0-beta.4'
 
+    - name: Check python-path
+      run: ./__tests__/check-python-path.sh '${{ steps.setup-python.outputs.python-path }}'
+      shell: bash
+
     - name: Validate version
       run: |
         $pythonVersion = (python --version)

.github/workflows/workflow.yml

@@ -89,3 +89,13 @@ jobs:
         python-version: 3.8.1
     - name: Verify 3.8.1
       run: python __tests__/verify-python.py 3.8.1
+
+    - name: Run with setup-python 3.10
+      id: cp310
+      uses: ./
+      with:
+        python-version: "3.10"
+    - name: Verify 3.10
+      run: python __tests__/verify-python.py 3.10
+    - name: Run python-path sample 3.10
+      run: pipx run --python '${{ steps.cp310.outputs.python-path }}' nox --version

README.md

@@ -137,6 +137,20 @@ jobs:
 ```
 More details on PyPy syntax and examples of using preview / nightly versions of PyPy can be found in the [Available versions of PyPy](#available-versions-of-pypy) section.
 
+An output is available with the absolute path of the python interpreter executable if you need it:
+```yaml
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - uses: actions/setup-python@v3
+      id: cp310
+      with:
+        python-version: "3.10"
+    - run: pipx run --python '${{ steps.cp310.outputs.python-path }}' nox --version
+```
+
 # Getting started with Python + Actions
 
 Check out our detailed guide on using [Python with GitHub Actions](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/using-python-with-github-actions).

__tests__/check-python-path.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+
+set -euo pipefail
+
+PYTHON_PATH="$1"
+PATH_EXECUTABLE=$(python -c 'import sys; print(sys.executable)')
+PYTHON_PATH_EXECUTABLE=$("${PYTHON_PATH}" -c 'import sys; print(sys.executable)')
+if [ "${PATH_EXECUTABLE}" != "${PYTHON_PATH_EXECUTABLE}" ]; then
+    echo "Executable mismatch."
+    echo "python in PATH is: ${PATH_EXECUTABLE}"
+    echo "python-path (${PYTHON_PATH}) is: ${PYTHON_PATH_EXECUTABLE}"
+    exit 1
+fi
+echo "python-path: ${PYTHON_PATH}"

action.yml

@@ -21,6 +21,8 @@ outputs:
     description: "The installed python version. Useful when given a version range as input."
   cache-hit:
     description: 'A boolean value to indicate a cache entry was found'
+  python-path:
+    description: "The absolute path to the Python executable."
 runs:
   using: 'node16'
   main: 'dist/setup/index.js'

dist/setup/index.js

@@ -52375,12 +52375,15 @@ function findPyPyVersion(versionSpec, architecture) {
         }
         const pipDir = utils_1.IS_WINDOWS ? 'Scripts' : 'bin';
         const _binDir = path.join(installDir, pipDir);
+        const binaryExtension = utils_1.IS_WINDOWS ? '.exe' : '';
+        const pythonPath = path.join(utils_1.IS_WINDOWS ? installDir : _binDir, `python${binaryExtension}`);
         const pythonLocation = pypyInstall.getPyPyBinaryPath(installDir);
         core.exportVariable('pythonLocation', pythonLocation);
         core.exportVariable('PKG_CONFIG_PATH', pythonLocation + '/lib/pkgconfig');
         core.addPath(pythonLocation);
         core.addPath(_binDir);
         core.setOutput('python-version', 'pypy' + resolvedPyPyVersion.trim());
+        core.setOutput('python-path', pythonPath);
         return { resolvedPyPyVersion, resolvedPythonVersion };
     });
 }
@@ -57027,8 +57030,11 @@ function useCpythonVersion(version, architecture) {
                 core.exportVariable('LD_LIBRARY_PATH', pyLibPath + libPath);
             }
         }
+        const _binDir = binDir(installDir);
+        const binaryExtension = utils_1.IS_WINDOWS ? '.exe' : '';
+        const pythonPath = path.join(utils_1.IS_WINDOWS ? installDir : _binDir, `python${binaryExtension}`);
         core.addPath(installDir);
-        core.addPath(binDir(installDir));
+        core.addPath(_binDir);
         if (utils_1.IS_WINDOWS) {
             // Add --user directory
             // `installDir` from tool cache should look like $RUNNER_TOOL_CACHE/Python/<semantic version>/x64/
@@ -57042,6 +57048,7 @@ function useCpythonVersion(version, architecture) {
         // On Linux and macOS, pip will create the --user directory and add it to PATH as needed.
         const installed = versionFromPath(installDir);
         core.setOutput('python-version', installed);
+        core.setOutput('python-path', pythonPath);
         return { impl: 'CPython', version: installed };
     });
 }

src/find-pypy.ts

@@ -48,12 +48,18 @@ export async function findPyPyVersion(
 
   const pipDir = IS_WINDOWS ? 'Scripts' : 'bin';
   const _binDir = path.join(installDir, pipDir);
+  const binaryExtension = IS_WINDOWS ? '.exe' : '';
+  const pythonPath = path.join(
+    IS_WINDOWS ? installDir : _binDir,
+    `python${binaryExtension}`
+  );
   const pythonLocation = pypyInstall.getPyPyBinaryPath(installDir);
   core.exportVariable('pythonLocation', pythonLocation);
   core.exportVariable('PKG_CONFIG_PATH', pythonLocation + '/lib/pkgconfig');
   core.addPath(pythonLocation);
   core.addPath(_binDir);
   core.setOutput('python-version', 'pypy' + resolvedPyPyVersion.trim());
+  core.setOutput('python-path', pythonPath);
 
   return {resolvedPyPyVersion, resolvedPythonVersion};
 }

src/find-python.ts

@@ -83,8 +83,14 @@ export async function useCpythonVersion(
     }
   }
 
+  const _binDir = binDir(installDir);
+  const binaryExtension = IS_WINDOWS ? '.exe' : '';
+  const pythonPath = path.join(
+    IS_WINDOWS ? installDir : _binDir,
+    `python${binaryExtension}`
+  );
   core.addPath(installDir);
-  core.addPath(binDir(installDir));
+  core.addPath(_binDir);
 
   if (IS_WINDOWS) {
     // Add --user directory
@@ -106,6 +112,7 @@ export async function useCpythonVersion(
 
   const installed = versionFromPath(installDir);
   core.setOutput('python-version', installed);
+  core.setOutput('python-path', pythonPath);
 
   return {impl: 'CPython', version: installed};
 }