release: Prevent virtualenv redirect from occupying .venv (#26168)

## Why
Backport of
[#26167](#26167) for the
2026.6 release branch. [virtualenv
21.12](https://github.com/pypa/virtualenv/releases/tag/21.12.0) began
writing a `.venv` redirect file when creating `.virtualenv` in a project
with `pyproject.toml`. The following `python -m venv .venv` then cannot
create the separate stdlib venv directory, breaking the release branch's
Windows and Linux venv jobs.

## Change
Pass `--no-venv-redirect` when creating `.virtualenv` so the existing
`.virtualenv` and `.venv` tests continue to use their original, separate
paths. Exit immediately if stdlib venv creation fails.

## Windows unit-test investigation
The Windows `ts-unit` job also intermittently failed on the first Native
Python Finder refresh while the subsequent refresh succeeded. The
locator-output diagnostic reproduced the failure: Pet logged `Skipping
refresh state sync for stale generation 0 because current generation is
1` and returned no environments. The finder had launched a configure
request in its constructor without awaiting it, while its first refresh
launched another configure and could start before the first completed.
Pet suppresses environment notifications from stale configuration
generations. Remove the redundant constructor configure; the first
refresh already configures and awaits completion before sending the
refresh request. The existing non-empty assertion is unchanged and still
includes the locator log on failure.

The release branch's Build workflow must pass after this lands before
releasing.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: eleanorjboyd

.github/workflows/build.yml

@@ -311,7 +311,7 @@ jobs:
         if: matrix.test-suite == 'venv'
         run: |
           python -m pip install virtualenv
-          python -m virtualenv .virtualenv/
+          python -m virtualenv --no-venv-redirect .virtualenv/
           if ('${{ matrix.os }}' -match 'windows-latest') {
             & ".virtualenv/Scripts/python.exe" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} virtualEnvPath
           } else {
@@ -326,10 +326,11 @@ jobs:
         if: matrix.test-suite == 'venv' && startsWith(matrix.python, 3.)
         run: |
           python -m venv .venv
+          if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
           if ('${{ matrix.os }}' -match 'windows-latest') {
-            & ".venv/Scripts/python.exe" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} venvPath
+            & "./.venv/Scripts/python.exe" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} venvPath
           } else {
-            & ".venv/bin/python" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} venvPath
+            & "./.venv/bin/python" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} venvPath
           }
 
       - name: Prepare conda for venv tests

.github/workflows/pr-check.yml

@@ -304,7 +304,7 @@ jobs:
         if: matrix.test-suite == 'venv'
         run: |
           python -m pip install virtualenv
-          python -m virtualenv .virtualenv/
+          python -m virtualenv --no-venv-redirect .virtualenv/
           if ('${{ matrix.os }}' -match 'windows-latest') {
             & ".virtualenv/Scripts/python.exe" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} virtualEnvPath
           } else {
@@ -319,10 +319,11 @@ jobs:
         if: matrix.test-suite == 'venv' && startsWith(matrix.python, 3.)
         run: |
           python -m venv .venv
+          if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
           if ('${{ matrix.os }}' -match 'windows-latest') {
-            & ".venv/Scripts/python.exe" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} venvPath
+            & "./.venv/Scripts/python.exe" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} venvPath
           } else {
-            & ".venv/bin/python" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} venvPath
+            & "./.venv/bin/python" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} venvPath
           }
 
       - name: Prepare conda for venv tests
@@ -584,7 +585,7 @@ jobs:
         shell: pwsh
         run: |
           python -m pip install virtualenv
-          python -m virtualenv .virtualenv/
+          python -m virtualenv --no-venv-redirect .virtualenv/
           if ('${{ matrix.os }}' -match 'windows-latest') {
             & ".virtualenv/Scripts/python.exe" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} virtualEnvPath
           } else {
@@ -598,10 +599,11 @@ jobs:
         shell: pwsh
         run: |
           python -m venv .venv
+          if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
           if ('${{ matrix.os }}' -match 'windows-latest') {
-            & ".venv/Scripts/python.exe" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} venvPath
+            & "./.venv/Scripts/python.exe" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} venvPath
           } else {
-            & ".venv/bin/python" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} venvPath
+            & "./.venv/bin/python" ./build/ci/addEnvPath.py ${{ env.PYTHON_VIRTUAL_ENVS_LOCATION }} venvPath
           }
 
       - name: Prepare conda for venv tests

src/client/pythonEnvironments/base/locators/common/nativePythonFinder.ts

@@ -120,7 +120,6 @@ class NativePythonFinderImpl extends DisposableBase implements NativePythonFinde
             ? getGlobalStorage<boolean>(this.context, DONT_SHOW_SPAWN_ERROR_AGAIN, false)
             : ({ get: () => false, set: async () => {} } as IPersistentStorage<boolean>);
         this.connection = this.start();
-        void this.configure();
         this.firstRefreshResults = this.refreshFirstTime();
     }
 

src/test/pythonEnvironments/nativePythonFinder.unit.test.ts

@@ -21,10 +21,11 @@ suite('Native Python Finder', () => {
     let getConfigurationStub: sinon.SinonStub;
     let configMock: typemoq.IMock<WorkspaceConfiguration>;
     let getWorkspaceFolderPathsStub: sinon.SinonStub;
+    const locatorOutput = new MockOutputChannel('locator');
 
     setup(() => {
         createLogOutputChannelStub = sinon.stub(windowsApis, 'createLogOutputChannel');
-        createLogOutputChannelStub.returns(new MockOutputChannel('locator'));
+        createLogOutputChannelStub.returns(locatorOutput);
 
         getWorkspaceFolderPathsStub = sinon.stub(workspaceApis, 'getWorkspaceFolderPaths');
         getWorkspaceFolderPathsStub.returns([]);
@@ -55,7 +56,7 @@ suite('Native Python Finder', () => {
         }
 
         // typically all test envs should have at least one environment
-        assert.isNotEmpty(envs);
+        assert.isNotEmpty(envs, `Python Locator output:\n${locatorOutput.output || '(none)'}`);
     });
 
     test('Resolve should return python environments with version', async () => {