engineering: use tar+zstd for win32 node_modules cache

[tmm1]

this is significantly faster in my tests, down to 60s vs 120-180s before in the Extract node_modules phase

GHA and Azure Pipelines images have tar.exe and zstandard bundled since a few years ago

(will need to bump cachesalt if merging, to invalidate old cache)

cc @lszomoru @deepak1556

[deepak1556]

Thanks! should also mirror this in .github/workflows/pr-node-modules.yml and .github/workflows/pr-win32-test.yml that is used for pr builds

[tmm1]

should also mirror this in .github/workflows/pr-node-modules.yml and .github/workflows/pr-win32-test.yml that is used for pr builds

Those paths already use tar but may see added speedups from zstd. For some reason whatever 7z does in the azure-pipeline is very slow.

[deepak1556]

Those paths already use tar but may see added speedups from zstd.

The windows jobs use 7z

vscode/.github/workflows/pr-win32-test.yml

Line 91 in d5e0905

exec { 7z.exe a .build/node_modules_cache/cache.7z -mx3 `@.build/node_modules_list.txt }

and

vscode/.github/workflows/pr-node-modules.yml

Line 293 in d5e0905

exec { 7z.exe a .build/node_modules_cache/cache.7z -mx3 `@.build/node_modules_list.txt }

[deepak1556]

@joaomoreno actually wrote the archive cache steps, I couldn't find from commit history why 7z was preferred for windows, maybe it was one of the reasons you had pointed out but lets wait for his review before pushing this forward. He is oof this week :)

I know win32 ships their own tar.exe but I think its bsd not gnutar and the options may not match.

[Copilot]

Pull request overview

Speeds up Win32 node_modules caching by switching from 7z archives to tar+zstd, aiming to reduce cache extraction time in CI.

Changes:

• Replace 7z.exe archive creation/extraction with tar.exe + zstd on Win32 (Azure Pipelines + GitHub Actions).
• Update cache artifact name from cache.7z to cache.tzst.
• Bump build/.cachesalt to invalidate existing caches.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
build/azure-pipelines/win32/steps/product-build-win32-compile.yml	Switch restore/extract + create cache archive steps to tar+zstd for win32 builds.
build/azure-pipelines/win32/product-build-win32-node-modules.yml	Switch node-modules cache archive creation to tar+zstd.
build/.cachesalt	Cache invalidation bump to force regeneration under new archive format.
.github/workflows/pr-win32-test.yml	Update Win32 PR workflow cache extract/create steps to tar+zstd.
.github/workflows/pr-node-modules.yml	Update Win32 node-modules workflow cache archive creation to tar+zstd.

Comments suppressed due to low confidence (2)

build/azure-pipelines/win32/steps/product-build-win32-compile.yml:113

• The archive creation uses tar’s -P (preserve absolute paths). Since listNodeModules.ts emits relative paths, -P isn’t needed and can make the resulting archive unsafe to extract if absolute/path-traversal entries ever get introduced. Prefer omitting -P so the archive contains only relative paths.

      exec { & "C:\Program Files\Git\usr\bin\tar.exe" --posix -cf .build/node_modules_cache/cache.tzst --exclude cache.tzst -P -C . --files-from .build/node_modules_list.txt --force-local --use-compress-program "zstd -T0" }

.github/workflows/pr-win32-test.yml:89

• The create-archive tar command includes -P (preserve absolute paths). Given the archive inputs are relative, -P is unnecessary and increases the risk of writing outside the workspace if unexpected entries ever make it into the cache archive. Prefer omitting -P for safer archives.

          exec { & "C:\Program Files\Git\usr\bin\tar.exe" --posix -cf .build/node_modules_cache/cache.tzst --exclude cache.tzst -P -C . --files-from .build/node_modules_list.txt --force-local --use-compress-program "zstd -T0" }

[joaomoreno]

Moving to #291624 due to engineering checks protections