@@ -65,3 +65,33 @@ jobs:
           EXECUTABLE=${EXECUTABLE%%-*}  # remove any -* suffixe
           ${EXECUTABLE} --version
         shell: bash
+
+  setup-pypy-noenv:
+    name: Setup PyPy ${{ matrix.pypy }} ${{ matrix.os }} (noenv)
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [macos-latest, windows-latest, ubuntu-18.04, ubuntu-latest]
+        pypy:
+        - 'pypy2.7'
+        - 'pypy3.7'
+        - 'pypy3.8'
+        - 'pypy3.9-nightly'
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: setup-python ${{ matrix.pypy }}
+        id: setup-python
+        uses: ./
+        with:
+          python-version: ${{ matrix.pypy }}
+          no-environment-update: true
+
+      - name: PyPy and Python version
+        run: ${{ steps.setup-python.outputs.python-path }} --version
+
+      - name: Run simple code
+        run: ${{ steps.setup-python.outputs.python-path }} -c 'import math; print(math.factorial(5))'
@@ -1,5 +1,5 @@
 name: Validate Python e2e
-on: 
+on:
   push:
     branches:
       - main
@@ -106,3 +106,27 @@ jobs:
     - name: Run simple code
       run: python -c 'import math; print(math.factorial(5))'
 
+  setup-versions-noenv:
+    name: Setup ${{ matrix.python }} ${{ matrix.os }} (noenv)
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [macos-latest, windows-latest, ubuntu-18.04, ubuntu-20.04]
+        python: ["3.7", "3.8", "3.9", "3.10"]
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v3
+
+    - name: setup-python ${{ matrix.python }}
+      id: setup-python
+      uses: ./
+      with:
+        python-version: ${{ matrix.python }}
+        no-environment-update: true
+
+    - name: Python version
+      run: ${{ steps.setup-python.outputs.python-path }} --version
+
+    - name: Run simple code
+      run: ${{ steps.setup-python.outputs.python-path }} -c 'import math; print(math.factorial(5))'
@@ -305,6 +305,26 @@ steps:
 - run: pipenv install
 ```
 
+# No environment update
+
+ The `no-environment-update` flag defaults to `false`.
+ With this setting, the action will add/update environment variables (e.g. `PATH`, `PKG_CONFIG_PATH`, `pythonLocation`) for `python` to just work out of the box.
+
+ If `no-environment-update` is set to `true`, the action will not add/update environment variables.
+ This can prove useful if you want the only side-effect to be to ensure python is installed and rely on the `python-path` output to run python.
+ Such a requirement on side-effect could be because you don't want your composite action messing with your user's workflows.
+
+ ```yaml
+ steps:
+   - uses: actions/checkout@v3
+   - uses: actions/setup-python@v3
+     id: cp310
+     with:
+       python-version: '3.10'
+       no-environment-update: true
+   - run: ${{ steps.cp310.outputs.python-path }} my_script.py
+ ```
+
 # Using `setup-python` with a self hosted runner
 
 Python distributions are only available for the same [environments](https://github.com/actions/virtual-environments#available-environments) that GitHub Actions hosted environments are available for. If you are using an unsupported version of Ubuntu such as `19.04` or another Linux distribution such as Fedora, `setup-python` will not work. If you have a supported self-hosted runner and you would like to use `setup-python`, there are a few extra things you need to make sure are set up so that new versions of Python can be downloaded and configured on your runner.
 
@@ -5,6 +5,7 @@ import {HttpClient} from '@actions/http-client';
 import * as ifm from '@actions/http-client/interfaces';
 import * as tc from '@actions/tool-cache';
 import * as exec from '@actions/exec';
+import * as core from '@actions/core';
 
 import * as path from 'path';
 import * as semver from 'semver';
@@ -148,6 +149,8 @@ describe('findPyPyVersion', () => {
   let spyWriteExactPyPyVersionFile: jest.SpyInstance;
   let spyCacheDir: jest.SpyInstance;
   let spyChmodSync: jest.SpyInstance;
+  let spyCoreAddPath: jest.SpyInstance;
+  let spyCoreExportVariable: jest.SpyInstance;
 
   beforeEach(() => {
     tcFind = jest.spyOn(tc, 'find');
@@ -201,6 +204,10 @@ describe('findPyPyVersion', () => {
 
     spyExistsSync = jest.spyOn(fs, 'existsSync');
     spyExistsSync.mockReturnValue(true);
+
+    spyCoreAddPath = jest.spyOn(core, 'addPath');
+
+    spyCoreExportVariable = jest.spyOn(core, 'exportVariable');
   });
 
   afterEach(() => {
@@ -211,22 +218,31 @@ describe('findPyPyVersion', () => {
 
   it('found PyPy in toolcache', async () => {
     await expect(
-      finder.findPyPyVersion('pypy-3.6-v7.3.x', architecture)
+      finder.findPyPyVersion('pypy-3.6-v7.3.x', architecture, true)
     ).resolves.toEqual({
       resolvedPythonVersion: '3.6.12',
       resolvedPyPyVersion: '7.3.3'
     });
+    expect(spyCoreAddPath).toHaveBeenCalled();
+    expect(spyCoreExportVariable).toHaveBeenCalledWith(
+      'pythonLocation',
+      expect.anything()
+    );
+    expect(spyCoreExportVariable).toHaveBeenCalledWith(
+      'PKG_CONFIG_PATH',
+      expect.anything()
+    );
   });
 
   it('throw on invalid input format', async () => {
     await expect(
-      finder.findPyPyVersion('pypy3.7-v7.3.x', architecture)
+      finder.findPyPyVersion('pypy3.7-v7.3.x', architecture, true)
     ).rejects.toThrow();
   });
 
   it('throw on invalid input format pypy3.7-7.3.x', async () => {
     await expect(
-      finder.findPyPyVersion('pypy3.7-v7.3.x', architecture)
+      finder.findPyPyVersion('pypy3.7-v7.3.x', architecture, true)
     ).rejects.toThrow();
   });
 
@@ -238,16 +254,42 @@ describe('findPyPyVersion', () => {
     spyChmodSync = jest.spyOn(fs, 'chmodSync');
     spyChmodSync.mockImplementation(() => undefined);
     await expect(
-      finder.findPyPyVersion('pypy-3.7-v7.3.x', architecture)
+      finder.findPyPyVersion('pypy-3.7-v7.3.x', architecture, true)
+    ).resolves.toEqual({
+      resolvedPythonVersion: '3.7.9',
+      resolvedPyPyVersion: '7.3.3'
+    });
+    expect(spyCoreAddPath).toHaveBeenCalled();
+    expect(spyCoreExportVariable).toHaveBeenCalledWith(
+      'pythonLocation',
+      expect.anything()
+    );
+    expect(spyCoreExportVariable).toHaveBeenCalledWith(
+      'PKG_CONFIG_PATH',
+      expect.anything()
+    );
+  });
+
+  it('found and install successfully without environment update', async () => {
+    spyCacheDir = jest.spyOn(tc, 'cacheDir');
+    spyCacheDir.mockImplementation(() =>
+      path.join(toolDir, 'PyPy', '3.7.7', architecture)
+    );
+    spyChmodSync = jest.spyOn(fs, 'chmodSync');
+    spyChmodSync.mockImplementation(() => undefined);
+    await expect(
+      finder.findPyPyVersion('pypy-3.7-v7.3.x', architecture, false)
     ).resolves.toEqual({
       resolvedPythonVersion: '3.7.9',
       resolvedPyPyVersion: '7.3.3'
     });
+    expect(spyCoreAddPath).not.toHaveBeenCalled();
+    expect(spyCoreExportVariable).not.toHaveBeenCalled();
   });
 
   it('throw if release is not found', async () => {
     await expect(
-      finder.findPyPyVersion('pypy-3.7-v7.5.x', architecture)
+      finder.findPyPyVersion('pypy-3.7-v7.5.x', architecture, true)
     ).rejects.toThrowError(
       `PyPy version 3.7 (v7.5.x) with arch ${architecture} not found`
     );
 
@@ -19,23 +19,54 @@ process.env['RUNNER_TOOL_CACHE'] = toolDir;
 process.env['RUNNER_TEMP'] = tempDir;
 
 import * as tc from '@actions/tool-cache';
+import * as core from '@actions/core';
 import * as finder from '../src/find-python';
 import * as installer from '../src/install-python';
 
 const manifestData = require('./data/versions-manifest.json');
 
 describe('Finder tests', () => {
+  let spyCoreAddPath: jest.SpyInstance;
+  let spyCoreExportVariable: jest.SpyInstance;
+
+  beforeEach(() => {
+    spyCoreAddPath = jest.spyOn(core, 'addPath');
+
+    spyCoreExportVariable = jest.spyOn(core, 'exportVariable');
+  });
+
   afterEach(() => {
     jest.resetAllMocks();
     jest.clearAllMocks();
+    jest.restoreAllMocks();
   });
 
   it('Finds Python if it is installed', async () => {
     const pythonDir: string = path.join(toolDir, 'Python', '3.0.0', 'x64');
     await io.mkdirP(pythonDir);
     fs.writeFileSync(`${pythonDir}.complete`, 'hello');
     // This will throw if it doesn't find it in the cache and in the manifest (because no such version exists)
-    await finder.useCpythonVersion('3.x', 'x64');
+    await finder.useCpythonVersion('3.x', 'x64', true);
+    expect(spyCoreAddPath).toHaveBeenCalled();
+    expect(spyCoreExportVariable).toHaveBeenCalledWith(
+      'pythonLocation',
+      expect.anything()
+    );
+    expect(spyCoreExportVariable).toHaveBeenCalledWith(
+      'PKG_CONFIG_PATH',
+      expect.anything()
+    );
+  });
+
+  it('Finds Python if it is installed without environment update', async () => {
+    const pythonDir: string = path.join(toolDir, 'Python', '3.0.0', 'x64');
+    await io.mkdirP(pythonDir);
+    fs.writeFileSync(`${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);
+    expect(spyCoreAddPath).not.toHaveBeenCalled();
+    expect(spyCoreExportVariable).not.toHaveBeenCalled();
+    expect(spyCoreExportVariable).not.toHaveBeenCalled();
   });
 
   it('Finds stable Python version if it is not installed, but exists in the manifest', async () => {
@@ -52,7 +83,16 @@ 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('1.2.3', 'x64');
+    await finder.useCpythonVersion('1.2.3', 'x64', true);
+    expect(spyCoreAddPath).toHaveBeenCalled();
+    expect(spyCoreExportVariable).toHaveBeenCalledWith(
+      'pythonLocation',
+      expect.anything()
+    );
+    expect(spyCoreExportVariable).toHaveBeenCalledWith(
+      'PKG_CONFIG_PATH',
+      expect.anything()
+    );
   });
 
   it('Finds pre-release Python version in the manifest', async () => {
@@ -74,17 +114,28 @@ describe('Finder tests', () => {
       fs.writeFileSync(`${pythonDir}.complete`, 'hello');
     });
     // This will throw if it doesn't find it in the manifest (because no such version exists)
-    await finder.useCpythonVersion('1.2.3-beta.2', 'x64');
+    await finder.useCpythonVersion('1.2.3-beta.2', 'x64', true);
+    expect(spyCoreAddPath).toHaveBeenCalled();
+    expect(spyCoreExportVariable).toHaveBeenCalledWith(
+      'pythonLocation',
+      expect.anything()
+    );
+    expect(spyCoreExportVariable).toHaveBeenCalledWith(
+      'PKG_CONFIG_PATH',
+      expect.anything()
+    );
   });
 
   it('Errors if Python is not installed', async () => {
     // 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');
+      await finder.useCpythonVersion('3.300000', 'x64', true);
     } catch {
       thrown = true;
     }
     expect(thrown).toBeTruthy();
+    expect(spyCoreAddPath).not.toHaveBeenCalled();
+    expect(spyCoreExportVariable).not.toHaveBeenCalled();
   });
 });
@@ -16,6 +16,9 @@ inputs:
     default: ${{ github.token }}
   cache-dependency-path:
     description: 'Used to specify the path to dependency files. Supports wildcards or a list of file names for caching multiple dependencies.'
+  no-environment-update:
+    description: 'Set this option if you want the action not to update environment variables.'
+    default: false
 outputs:
   python-version:
     description: "The installed python version. Useful when given a version range as input."