mirror of https://github.com/pnpm/pnpm.git synced 2026-03-26 11:02:01 -04:00

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Victor Sumner ee9fe5853e perf(importer): skip staging directory and write package.json as completion marker (#11088 )

## Problem

The indexed package importer always creates a staging temp directory, imports files there, then renames to the final location. For cold installs where the target doesn't exist (the common case), the staging + rename is unnecessary overhead.

## Solution

- **Fast path**: callers already verify the target package is missing before calling `importIndexedDir`, so we can write directly into the final directory and skip the temp dir + rename. Falls back to the atomic staging path on EEXIST (concurrent import race) or when `keepModulesDir` is set (hoisted linker needs to merge existing `node_modules`).

- **Completion marker**: `package.json` is written last by `tryImportIndexedDir`, so `pkgExistsAtTargetDir()` (which checks for `package.json`) won't consider a partially-imported directory as complete after a crash.

- **Atomic copy**: the copy import path (non-COW filesystems) uses a temp file + `renameOverwriteSync` for the `package.json` write, since `copyFileSync` is not atomic. Hard links and reflinks are inherently atomic. This is expressed via the `Importer` interface (`importFile` + `importFileAtomic`), passed as the first argument to `importIndexedDir`.

- **Synthetic package.json**: packages that lack a `package.json` (e.g. injected Bit workspace packages) now get a synthetic empty `{}` added to the store, so the completion marker works universally.

- **DRY**: extracted `retryWithSanitizedFilenames()` to deduplicate the ENOENT handler used by both the fast path and staging path.

2026-03-25 23:16:08 +01:00