Move SQLite reads/writes, JSON.parse, semver matching, and version
picking from the main thread to the existing worker pool.
The main thread is now a thin orchestrator that only does network I/O.
Resolution uses at most 2 round-trips to the worker:
1. Worker checks SQLite cache → cache hit returns immediately
2. On cache miss, main thread fetches from registry, sends raw JSON
to worker → worker parses, writes cache, picks version
This unblocks the main event loop during resolution — network I/O,
tarball downloads, and linking can proceed while the worker does
CPU-heavy parsing and semver matching.
Replace the per-package JSON file cache (metadata-v1.4/, metadata-ff-v1.4/)
with a single SQLite database (metadata.db) for registry metadata caching.
Benefits:
- Cheap conditional request header lookups (etag/modified) without parsing
the full metadata JSON — enables If-None-Match/If-Modified-Since with
minimal I/O overhead
- Full metadata can serve abbreviated requests — if a package was previously
fetched as full (e.g., for trustPolicy or resolutionMode), the resolver
reuses it instead of making another registry request
- Eliminates hundreds of individual file read/write/rename operations per
install, replaced by SQLite WAL-mode transactions
- Removes the runLimited/metafileOperationLimits concurrency machinery —
SQLite handles concurrent access natively
New package: @pnpm/cache.metadata — SQLite-backed MetadataCache class
modeled after @pnpm/store.index, with getHeaders() for cheap lookups,
get() with abbreviated→full fallback, and set()/updateCachedAt().
Replace node-fetch with native undici for HTTP requests throughout pnpm.
Key changes:
- Replace node-fetch with undici's fetch() and dispatcher system
- Replace @pnpm/network.agent with a new dispatcher module in @pnpm/network.fetch
- Cache dispatchers via LRU cache keyed by connection parameters
- Handle proxies via undici ProxyAgent instead of http/https-proxy-agent
- Convert test mocking from nock to undici MockAgent where applicable
- Add minimatch@9 override to fix ESM incompatibility with brace-expansion
