Prefer Python Install Manager for Windows Python acquisition

[Stella Huang (StellaHuang95)]

Summary

• prefer an existing Python Install Manager on Windows for base-Python acquisition, while retaining uv when PyManager is absent
• share provider selection across Global creation, project venv creation, activation-time acquisition, and PEP 723 inline-script setup
• verify the actual installed CPython interpreter, serialize PyManager mutations, prevent unsafe downgrades, and pause package watchers during in-place runtime updates
• supplement Global discovery with verified PyManager-owned runtimes while preserving existing uv-managed interpreter behavior
• surface provider-specific cancellation and failure states without starting a second installer or publishing partial selections

Validation

• npm run lint
• npm run compile-tests
• npm run unittest — 3,306 passing, 9 pending
• npm run compile
• npm run smoke-test — 30 passing, 1 pending
• npm run e2e-test — 4 passing
• non-interactive integration suite — 60 passing, 5 pending
• multi-root integration suite — 3 passing, 1 pending
• native Windows PyManager probes succeeded for installed, online, and --one JSON listings (82 online catalogue entries)

The full integration run reached 60 passing and 8 pending, with the existing interactive environment-creation case timing out because the headless VS Code test host cannot answer the real Global Python version picker. The equivalent provider picker and creation flows were verified manually in an Extension Development Host.

[Rich Chiodo (rchiodo)]

🔒 Automated review in progress — Rich Chiodo (@rchiodo) is auto-reviewing this PR.

[Rich Chiodo (rchiodo)]

Result: ⚠️ partially-verified

Verification details

Verification: Isolated verification observed failures that were not classified as caused by this PR: Dependency and test-runner discovery.

Summary: Test compilation and three targeted Mocha runs passed: 972 passing tests and five pending. Coverage included provider selection, interpreter verification, mutation serialization, downgrade prevention, watcher coordination, discovery, venv creation, inline scripts, and uv regressions. Offline dependency installation succeeded; discovery exited 128 because the container snapshot lacked Git metadata. Native Windows PyManager and Electron-hosted integration flows were not exercised, so verification remains partial.

Test runs: 5 passed, 1 failed

• ❌ Failed | unrelated to this PR | Dependency and test-runner discovery | printf 'Sandbox profile: %s\n' "$AUTOMATION_SANDBOX_PROFILE"; node --version; npm --version; git status --short; node -e "const p=require('./package.json'); console.log(JSON.stringify({scripts:p.scripts,engines:p.engines},null,2)); const fs=require('fs'); for (const f of ['node_modules','node_modules/mocha/bin/mocha.js','node_modules/typescript/bin/tsc','out/test/unittests.js']) console.log(f,fs.existsSync(f));"; cat build/.mocha.unittests.json; sed -n '1,110p' src/test/unittests.ts; git log -1 --oneline
• ✅ Passed | Installer process, PyManager detection, runtime candidates, and provider orchestration | node ./node_modules/mocha/bin/mocha.js --no-config --require source-map-support/register --require ./out/test/unittests.js --ui tdd --timeout 20000 --reporter dot out/test/common/installerProcess.unit.test.js out/test/managers/builtin/pymanagerPythonInstaller.unit.test.js out/test/managers/builtin/pythonRuntimeCandidates.unit.test.js out/test/managers/builtin/pythonInstaller.unit.test.js
• ✅ Passed | Watcher coordination, system discovery, saved selection, venv creation, and fast paths | node ./node_modules/mocha/bin/mocha.js --no-config --require source-map-support/register --require ./out/test/unittests.js --ui tdd --timeout 20000 --reporter dot out/test/managers/common/packageWatcher.unit.test.js out/test/managers/builtin/sysPythonManager.pymanager.unit.test.js out/test/managers/builtin/sysPythonManager.savedSelection.unit.test.js out/test/managers/builtin/venvManager.createRemove.unit.test.js out/test/managers/fastPath.get.unit.test.js
• ✅ Passed | Inline-script integration, onboarding isolation, tool managers, and uv regressions | node ./node_modules/mocha/bin/mocha.js --no-config --require source-map-support/register --require ./out/test/unittests.js --ui tdd --timeout 20000 --reporter dot out/test/features/inlineScript/setupEnvironment.unit.test.js out/test/managers/builtin/inlineScript/envManager.unit.test.js out/test/internal/discoveryIsolation.unit.test.js out/test/internal/pythonToolManagers.unit.test.js out/test/managers/builtin/uvPythonInstaller.unit.test.js out/test/managers/builtin/uvManagedPythonInstall.unit.test.js out/test/managers/builtin/venvUtils.uvTracking.unit.test.js
• ✅ Passed | Offline dependency bootstrap | npm ci --offline --frozen-lockfile
• ✅ Passed | TypeScript test compilation | npm run compile-tests

❌ Dependency and test-runner discovery diagnostic output

Sandbox profile: typescript
v22.21.1
10.9.4
node_modules false
node_modules/mocha/bin/mocha.js false
node_modules/typescript/bin/tsc false
out/test/unittests.js false
fatal: not a git repository (or any parent up to mount point /)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
[container exit=128]

[Rich Chiodo (rchiodo)]

Approved via Review Center.

[Bill Schnurr (bschnurr)]

Approved via Review Center.

[Heejae Chang (heejaechang)]

Approved via Review Center.