[build-utils] Improve memory efficiency in FileBlob.fromStream() by ofhouse · Pull Request #14701 · vercel/vercel

ofhouse · 2026-01-22T14:28:42Z

Summary

Avoids unnecessary buffer copies in FileBlob.fromStream() when stream chunks are already Buffer instances
Reduces peak memory usage from ~3x to ~2x file size during stream collection

Details

The previous implementation always called Buffer.from(chunk), which copies data even when chunk is already a Buffer. For a 100MB file with 64KB chunks, this created ~1,600 unnecessary buffer copies, effectively doubling memory usage during stream collection.

The fix adds a Buffer.isBuffer() check to only copy when necessary (e.g., when chunks are strings or other types).

changeset-bot · 2026-01-22T14:28:47Z

🦋 Changeset detected

Latest commit: fb6d1b7

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 13 packages

Name	Type
@vercel/build-utils	Patch
vercel	Patch
@vercel/client	Patch
@vercel/elysia	Patch
@vercel/express	Patch
@vercel/fastify	Patch
@vercel/gatsby-plugin-vercel-builder	Patch
@vercel/h3	Patch
@vercel/hono	Patch
@vercel/koa	Patch
@vercel/nestjs	Patch
@vercel/node	Patch
@vercel/static-build	Patch

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github-actions · 2026-01-22T14:32:08Z

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github-actions · 2026-01-22T14:33:47Z

🧪 Unit Test Strategy

Comparing: ee44634 → fb6d1b7 (view diff)

Strategy: Code changed outside of a package - running all unit tests

⚠️ All unit tests will run because global code changes could impact all packages.

Affected packages - 41 (100%)

@vercel-internals/get-package-json
@vercel/backends
@vercel/build-utils
@vercel/cervel
@vercel/cli-auth
@vercel/client
@vercel/config
@vercel/detect-agent
@vercel/edge
@vercel/elysia
@vercel/error-utils
@vercel/express
@vercel/fastify
@vercel/firewall
@vercel/frameworks
@vercel/fs-detectors
@vercel/functions
@vercel/gatsby-plugin-vercel-builder
@vercel/go
@vercel/h3
@vercel/hono
@vercel/hydrogen
@vercel/introspection
@vercel/koa
@vercel/nestjs
@vercel/next
@vercel/node
@vercel/oidc
@vercel/oidc-aws-credentials-provider
@vercel/python
@vercel/python-analysis
@vercel/redwood
@vercel/related-projects
@vercel/remix-builder
@vercel/routing-utils
@vercel/ruby
@vercel/rust
@vercel/static-build
@vercel/static-config
examples
vercel

Results

Unit tests: All affected packages will run unit tests
E2E tests: Handled separately (Version Packages PRs or run-e2e-tests label)
Type checks: All affected packages will run type checks

This comment is automatically generated based on the affected testing strategy

This PR was opened by the [Changesets release](https://github.com/changesets/action) GitHub action. When you're ready to do a release, you can merge this and the packages will be published to npm automatically. If you're not ready to do a release yet, that's fine, whenever you add more changesets to main, this PR will be updated. # Releases ## @vercel/frameworks@3.17.0 ### Minor Changes - Add experimental Go runtime framework preset. ([#14865](#14865)) This adds support for deploying standalone Go HTTP servers (using `package main` with `func main()`) in addition to the existing serverless function pattern. The preset supports: - `main.go` at project root (simple projects) - `cmd/api/main.go` (API servers) - `cmd/server/main.go` (HTTP servers) The Go application must listen on the port specified by the `PORT` environment variable. ## @vercel/go@3.4.0 ### Minor Changes - Add experimental Go runtime framework preset. ([#14865](#14865)) This adds support for deploying standalone Go HTTP servers (using `package main` with `func main()`) in addition to the existing serverless function pattern. The preset supports: - `main.go` at project root (simple projects) - `cmd/api/main.go` (API servers) - `cmd/server/main.go` (HTTP servers) The Go application must listen on the port specified by the `PORT` environment variable. ## @vercel/backends@0.0.29 ### Patch Changes - Updated dependencies \[[`fc357e11cb4b00ab8ec413a0ea3586a87e733f0e`](fc357e1), [`ff320caa5c8a0857aad0b989699207a6a703256f`](ff320ca)]: - @vercel/build-utils@13.3.2 ## @vercel/build-utils@13.3.2 ### Patch Changes - Improve memory efficiency in `FileBlob.fromStream()` by avoiding unnecessary buffer copies when chunks are already Buffers ([#14701](#14701)) - [services] build time service url env vars ([#14893](#14893)) - Updated dependencies \[[`7a747344dfb778a650da2ee5f7fba8c974098b42`](7a74734)]: - @vercel/python-analysis@0.3.1 ## @vercel/cervel@0.0.16 ### Patch Changes - Updated dependencies \[]: - @vercel/backends@0.0.29 ## vercel@50.12.2 ### Patch Changes - Add source and defaultResourceName query params to legacy integration add web UI path ([#14868](#14868)) - [services] build time service url env vars ([#14893](#14893)) - Updated dependencies \[[`fc357e11cb4b00ab8ec413a0ea3586a87e733f0e`](fc357e1), [`84f121190813b2840a6a16279dcaa75dcb2872cd`](84f1211), [`ff320caa5c8a0857aad0b989699207a6a703256f`](ff320ca)]: - @vercel/build-utils@13.3.2 - @vercel/go@3.4.0 - @vercel/backends@0.0.29 - @vercel/elysia@0.1.31 - @vercel/express@0.1.40 - @vercel/fastify@0.1.34 - @vercel/h3@0.1.40 - @vercel/hono@0.2.34 - @vercel/hydrogen@1.3.5 - @vercel/koa@0.1.14 - @vercel/nestjs@0.2.35 - @vercel/next@4.15.23 - @vercel/node@5.5.32 - @vercel/python@6.6.0 - @vercel/redwood@2.4.9 - @vercel/remix-builder@5.5.10 - @vercel/ruby@2.2.5 - @vercel/rust@1.0.5 - @vercel/static-build@2.8.33 ## @vercel/client@17.2.35 ### Patch Changes - Updated dependencies \[[`fc357e11cb4b00ab8ec413a0ea3586a87e733f0e`](fc357e1), [`ff320caa5c8a0857aad0b989699207a6a703256f`](ff320ca)]: - @vercel/build-utils@13.3.2 ## @vercel/elysia@0.1.31 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.5.32 ## @vercel/express@0.1.40 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.5.32 - @vercel/cervel@0.0.16 ## @vercel/fastify@0.1.34 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.5.32 ## @vercel/fs-detectors@5.8.2 ### Patch Changes - Updated dependencies \[[`84f121190813b2840a6a16279dcaa75dcb2872cd`](84f1211)]: - @vercel/frameworks@3.17.0 ## @vercel/gatsby-plugin-vercel-builder@2.0.131 ### Patch Changes - Updated dependencies \[[`fc357e11cb4b00ab8ec413a0ea3586a87e733f0e`](fc357e1), [`ff320caa5c8a0857aad0b989699207a6a703256f`](ff320ca)]: - @vercel/build-utils@13.3.2 ## @vercel/h3@0.1.40 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.5.32 ## @vercel/hono@0.2.34 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.5.32 ## @vercel/koa@0.1.14 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.5.32 ## @vercel/nestjs@0.2.35 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.5.32 ## @vercel/node@5.5.32 ### Patch Changes - Updated dependencies \[[`fc357e11cb4b00ab8ec413a0ea3586a87e733f0e`](fc357e1), [`ff320caa5c8a0857aad0b989699207a6a703256f`](ff320ca)]: - @vercel/build-utils@13.3.2 ## @vercel/python-analysis@0.3.1 ### Patch Changes - fix ESM/CJS cross-compatibility ([#14869](#14869)) ## @vercel/static-build@2.8.33 ### Patch Changes - Updated dependencies \[]: - @vercel/gatsby-plugin-vercel-builder@2.0.131 Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

[build-utils] Improve memory efficiency in FileBlob.fromStream()

fb6d1b7

ofhouse force-pushed the ofhouse/fix-fileblob-memory-efficiency branch from 9da4eb1 to fb6d1b7 Compare January 22, 2026 14:29

vercel bot deployed to Preview January 22, 2026 14:32 View deployment

ofhouse marked this pull request as ready for review February 5, 2026 21:05

ofhouse requested a review from a team as a code owner February 5, 2026 21:05

ofhouse requested review from ali-vercel, healeycodes and janory February 5, 2026 21:08

ali-vercel approved these changes Feb 5, 2026

View reviewed changes

ofhouse merged commit fc357e1 into main Feb 5, 2026
265 of 273 checks passed

ofhouse deleted the ofhouse/fix-fileblob-memory-efficiency branch February 5, 2026 21:14

vercel-release-bot mentioned this pull request Feb 5, 2026

Version Packages #14890

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[build-utils] Improve memory efficiency in FileBlob.fromStream()#14701

[build-utils] Improve memory efficiency in FileBlob.fromStream()#14701
ofhouse merged 1 commit intomainfrom
ofhouse/fix-fileblob-memory-efficiency

ofhouse commented Jan 22, 2026

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changeset-bot bot commented Jan 22, 2026 •

edited

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ofhouse commented Jan 22, 2026

Summary

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🧪 Unit Test Strategy

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changeset-bot bot commented Jan 22, 2026 •

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