[Ladislau Szomoru (lszomoru)]

Follow-up of #347275, for #345429: chat-lib - Test (Windows) is the last job of pr.yml that installs the workspace dependencies without starting from a workspace image, apart from Windows / Electron-Smoke (WSL) on the 1ES pool.

What changes

• Runner: chat-lib - Test (Windows) moves from windows-2025 to vscode-large-runners-windows-8-core. An image can only be used on the runners that build it, as it holds the workspace at the path of their workspaces.
• Image steps: like chat-lib - Test (Linux), the job reuses the download, Node.js and restore steps of Compile & Hygiene (YAML anchors), gets actions: read to find and download the image, and checks out with clean: false when it mounted one.
• Without an image (none of main, a pull request to a release branch, other native build inputs, or an error or timeout of the restore), it installs everything with a plain pnpm install, without the pnpm store cache, like the other pr.yml jobs that use the images (restore-pnpm-store: 'false').
• Windows: it sets GODEBUG=winreadlinkvolume=1, like Copilot - Test (Windows) and pr-win32-test.yml, so that esbuild resolves pnpm's junctions on the image, which is mounted without a drive letter.
• Guard test and docs: workspaceImage.test.ts checks that the job downloads the image scripts like the jobs that build the images, and the workspace image README no longer lists it as an exception.

Reviewers should know

• The job now takes one of the larger Windows runners on every pull request that changes Copilot, which the PR checks share with the Windows test jobs.
• In recent runs, the job took about 2.5–3 minutes on windows-2025, most of it in the Test chat-lib step, which installs Copilot and chat-lib. Copilot - Test (Windows), which installs the same projects, restored the image in about 33 s and installed in about 7 s on the larger runner.
• Without an image, the job now downloads every package instead of restoring the store cache. The manual chat-lib-package.yml workflow still uses the store cache, so pr-pnpm-store.yml keeps warming pnpm-store-copilot-windows.

How to test

This pull request's own checks run the job: its summary reports that it restored the image, or a Workspace image warning when it installed everything instead.

• cd build && node --test lib/test/workspaceImage.test.ts lib/test/detectChanges.test.ts lib/test/detectMissingCaches.test.ts lib/test/agentHostTestSelection.test.ts: passed, 36 tests.
• cd build && pnpm run typecheck: passed.
• ./node_modules/.bin/eslint build/lib/test/workspaceImage.test.ts: passed.
• actionlint -shellcheck= .github/workflows/pr.yml (actionlint 1.7.12): passed, apart from the custom runner labels.
• Not run locally: the job itself on an image, which this pull request's checks cover.

🤖 Authored with GitHub Copilot on behalf of Ladislau Szomoru (@lszomoru).

[Copilot]

🟢 Approval recommended

No active review issues remain for the change extending workspace-image reuse to the Windows chat-lib PR job.

No open issues 🎉

What changed in this PR

Extends workspace-image reuse to the Windows chat-lib PR job, following the earlier migration of other dependency-installing jobs.

Changes:

• Moves the job to the compatible larger Windows runner and reuses shared image-restore steps.
• Preserves restored dependencies, enables Windows junction resolution, and disables pnpm store-cache restoration.
• Extends the guard test and updates documentation to include Windows chat-lib.

No actionable findings remain. Image-backed Windows execution was not tested locally and relies on the PR checks.

File	Description
build/​lib/​test/​workspaceImage.test.ts	Adds Windows chat-lib to the image-script consistency check.
.github/​workflows/​workspace_image/​README.md	Removes Windows chat-lib from the image-adoption exceptions.
.github/​workflows/​pr.yml	Configures Windows chat-lib to restore and use workspace images.

_{Review effort: Balanced}