[build-utils] Extend finalizeLambda with pluggable ZIP strategy and pre-digest validation hook by healeycodes · Pull Request #15856 · vercel/vercel

healeycodes · 2026-04-07T13:29:33Z

Callers that handle large functions (multi-GiB) need to stream zips to disk instead of holding them in memory. The current finalizeLambda always creates an in-memory Buffer, forcing callers to duplicate the entire finalization pipeline (encrypted env, environment setup, streaming detection) just to swap out the zip step.

Additionally, callers need to validate zip size before sha256 runs so the size check must come first.

How

Add optional createZip callback to FinalizeLambdaParams. Callers can provide a custom ZIP strategy (e.g. streaming to disk) and the shared function handles everything else
Add optional validateZip hook that runs after zip creation but before digest computation
Add size and zipPath to FinalizeLambdaResult` so callers don't need to re-derive them
Extend TraceFn with optional tags param so callers can attach tracing metadata
Widen getLambdaEnvironment / getLambdaPreloadScripts buffer param from Buffer to { byteLength: number } (this is what was actually used, removes the need for as Buffer casts when the zip is on disk.
Export new types: CreateZipResult, CreateZipFn

Notes

No behavioral change for callers that don't use the new params
All new params are optional with backward-compatible defaults

…re-digest validation hook

changeset-bot · 2026-04-07T13:29:42Z

🦋 Changeset detected

Latest commit: d8db542

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

This PR includes changesets to release 16 packages

Name	Type
@vercel/build-utils	Minor
@vercel/backends	Patch
vercel	Patch
@vercel/client	Patch
@vercel/elysia	Patch
@vercel/express	Patch
@vercel/fastify	Patch
@vercel/fs-detectors	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
@vercel/cervel	Patch

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github-actions · 2026-04-07T13:30:37Z

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vercel · 2026-04-07T13:31:29Z

Low Risk — Additive API extension with optional params and backward-compatible defaults.

finalize-lambda.ts: added optional createZip callback and validateZip hook params
finalize-lambda.ts: extended FinalizeLambdaResult with size and zipPath fields
get-lambda-environment.ts, get-lambda-preload-scripts.ts: widened buffer param type from Buffer to { byteLength: number }

^{Assessed at d8db542.}

github-actions · 2026-04-07T13:36:11Z

🧪 Unit Test Strategy

Comparing: 280d949 → d8db542 (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 - 40 (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/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: Running in parallel via E2E Tests workflow
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/build-utils@13.13.0 ### Minor Changes - Extend `finalizeLambda` with pluggable ZIP strategy (`createZip`), pre-digest validation hook (`validateZip`), and optional trace tags. Widen `getLambdaEnvironment` buffer param to `{ byteLength: number }`. ([#15856](#15856)) ## vercel@50.41.0 ### Minor Changes - Add `vercel edge-config` with `list`, `add`, `get`, `update`, `remove`, `items`, and `tokens` subcommands for Edge Config dashboard API parity. ([#15822](#15822)) - Add `vercel project checks` to list a project's deployment checks configuration (parity with dashboard), including `--format json` and non-interactive error payloads. ([#15816](#15816)) ### Patch Changes - Improve `vercel teams request` in non-interactive mode: validation, missing team scope, and API errors emit structured JSON on stdout with stable `reason` values and `next[]` commands that preserve global flags (for example `--cwd` and `--non-interactive`). ([#15815](#15815)) - Hide `--search` flag from `vc logs --help` output while continuing to accept it, and update the `--query` flag description to indicate advanced querying with filter syntax support. ([#15854](#15854)) - Updated dependencies \[[`a80217a9ed60d7b7f3e98537b0468cc5488078c1`](a80217a)]: - @vercel/build-utils@13.13.0 - @vercel/backends@0.0.56 - @vercel/elysia@0.1.59 - @vercel/express@0.1.69 - @vercel/fastify@0.1.62 - @vercel/go@3.4.7 - @vercel/h3@0.1.68 - @vercel/hono@0.2.62 - @vercel/hydrogen@1.3.6 - @vercel/koa@0.1.42 - @vercel/nestjs@0.2.63 - @vercel/next@4.16.5 - @vercel/node@5.7.1 - @vercel/python@6.29.0 - @vercel/redwood@2.4.12 - @vercel/remix-builder@5.7.2 - @vercel/ruby@2.3.2 - @vercel/rust@1.0.6 - @vercel/static-build@2.9.9 ## @vercel/backends@0.0.56 ### Patch Changes - Updated dependencies \[[`a80217a9ed60d7b7f3e98537b0468cc5488078c1`](a80217a)]: - @vercel/build-utils@13.13.0 ## @vercel/cervel@0.0.43 ### Patch Changes - Updated dependencies \[]: - @vercel/backends@0.0.56 ## @vercel/client@17.2.68 ### Patch Changes - Updated dependencies \[[`a80217a9ed60d7b7f3e98537b0468cc5488078c1`](a80217a)]: - @vercel/build-utils@13.13.0 ## @vercel/elysia@0.1.59 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 ## @vercel/express@0.1.69 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 - @vercel/cervel@0.0.43 ## @vercel/fastify@0.1.62 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 ## @vercel/fs-detectors@5.14.3 ### Patch Changes - Updated dependencies \[[`a80217a9ed60d7b7f3e98537b0468cc5488078c1`](a80217a)]: - @vercel/build-utils@13.13.0 ## @vercel/gatsby-plugin-vercel-builder@2.1.9 ### Patch Changes - Updated dependencies \[[`a80217a9ed60d7b7f3e98537b0468cc5488078c1`](a80217a)]: - @vercel/build-utils@13.13.0 ## @vercel/h3@0.1.68 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 ## @vercel/hono@0.2.62 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 ## @vercel/koa@0.1.42 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 ## @vercel/nestjs@0.2.63 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 ## @vercel/node@5.7.1 ### Patch Changes - Updated dependencies \[[`a80217a9ed60d7b7f3e98537b0468cc5488078c1`](a80217a)]: - @vercel/build-utils@13.13.0 ## @vercel/static-build@2.9.9 ### Patch Changes - Updated dependencies \[]: - @vercel/gatsby-plugin-vercel-builder@2.1.9 Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

…re-digest validation hook (#15856) Callers that handle large functions (multi-GiB) need to stream zips to disk instead of holding them in memory. The current `finalizeLambda` always creates an in-memory `Buffer`, forcing callers to duplicate the entire finalization pipeline (encrypted env, environment setup, streaming detection) just to swap out the zip step. Additionally, callers need to validate zip size before `sha256` runs so the size check must come first. ### How - Add optional `createZip` callback to `FinalizeLambdaParams`. Callers can provide a custom ZIP strategy (e.g. streaming to disk) and the shared function handles everything else - Add optional `validateZip` hook that runs after zip creation but before digest computation - Add `size` and `zipPath to `FinalizeLambdaResult` so callers don't need to re-derive them - Extend `TraceFn` with optional tags param so callers can attach tracing metadata - Widen `getLambdaEnvironment` / `getLambdaPreloadScripts` `buffer` param from `Buffer` to `{ byteLength: number }` (this is what was actually used, removes the need for `as Buffer` casts when the zip is on disk. - Export new types: `CreateZipResult`, `CreateZipFn` ### Notes - No behavioral change for callers that don't use the new params - All new params are optional with backward-compatible defaults

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/build-utils@13.13.0 ### Minor Changes - Extend `finalizeLambda` with pluggable ZIP strategy (`createZip`), pre-digest validation hook (`validateZip`), and optional trace tags. Widen `getLambdaEnvironment` buffer param to `{ byteLength: number }`. ([#15856](#15856)) ## vercel@50.41.0 ### Minor Changes - Add `vercel edge-config` with `list`, `add`, `get`, `update`, `remove`, `items`, and `tokens` subcommands for Edge Config dashboard API parity. ([#15822](#15822)) - Add `vercel project checks` to list a project's deployment checks configuration (parity with dashboard), including `--format json` and non-interactive error payloads. ([#15816](#15816)) ### Patch Changes - Improve `vercel teams request` in non-interactive mode: validation, missing team scope, and API errors emit structured JSON on stdout with stable `reason` values and `next[]` commands that preserve global flags (for example `--cwd` and `--non-interactive`). ([#15815](#15815)) - Hide `--search` flag from `vc logs --help` output while continuing to accept it, and update the `--query` flag description to indicate advanced querying with filter syntax support. ([#15854](#15854)) - Updated dependencies \[[`a80217a9ed60d7b7f3e98537b0468cc5488078c1`](a80217a)]: - @vercel/build-utils@13.13.0 - @vercel/backends@0.0.56 - @vercel/elysia@0.1.59 - @vercel/express@0.1.69 - @vercel/fastify@0.1.62 - @vercel/go@3.4.7 - @vercel/h3@0.1.68 - @vercel/hono@0.2.62 - @vercel/hydrogen@1.3.6 - @vercel/koa@0.1.42 - @vercel/nestjs@0.2.63 - @vercel/next@4.16.5 - @vercel/node@5.7.1 - @vercel/python@6.29.0 - @vercel/redwood@2.4.12 - @vercel/remix-builder@5.7.2 - @vercel/ruby@2.3.2 - @vercel/rust@1.0.6 - @vercel/static-build@2.9.9 ## @vercel/backends@0.0.56 ### Patch Changes - Updated dependencies \[[`a80217a9ed60d7b7f3e98537b0468cc5488078c1`](a80217a)]: - @vercel/build-utils@13.13.0 ## @vercel/cervel@0.0.43 ### Patch Changes - Updated dependencies \[]: - @vercel/backends@0.0.56 ## @vercel/client@17.2.68 ### Patch Changes - Updated dependencies \[[`a80217a9ed60d7b7f3e98537b0468cc5488078c1`](a80217a)]: - @vercel/build-utils@13.13.0 ## @vercel/elysia@0.1.59 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 ## @vercel/express@0.1.69 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 - @vercel/cervel@0.0.43 ## @vercel/fastify@0.1.62 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 ## @vercel/fs-detectors@5.14.3 ### Patch Changes - Updated dependencies \[[`a80217a9ed60d7b7f3e98537b0468cc5488078c1`](a80217a)]: - @vercel/build-utils@13.13.0 ## @vercel/gatsby-plugin-vercel-builder@2.1.9 ### Patch Changes - Updated dependencies \[[`a80217a9ed60d7b7f3e98537b0468cc5488078c1`](a80217a)]: - @vercel/build-utils@13.13.0 ## @vercel/h3@0.1.68 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 ## @vercel/hono@0.2.62 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 ## @vercel/koa@0.1.42 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 ## @vercel/nestjs@0.2.63 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.1 ## @vercel/node@5.7.1 ### Patch Changes - Updated dependencies \[[`a80217a9ed60d7b7f3e98537b0468cc5488078c1`](a80217a)]: - @vercel/build-utils@13.13.0 ## @vercel/static-build@2.9.9 ### Patch Changes - Updated dependencies \[]: - @vercel/gatsby-plugin-vercel-builder@2.1.9 Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Follow up to: - #15856 After using the exported functions for existing callers, I realized we didn't get the `zipPath` type correct. As the goal is to avoid any semantic changes for existing callers, we have to fix it here.

[build-utils] Extend finalizeLambda with pluggable ZIP strategy and p…

0edb86d

…re-digest validation hook

healeycodes requested a review from ofhouse April 7, 2026 13:29

healeycodes requested a review from a team as a code owner April 7, 2026 13:29

vercel Bot deployed to Preview April 7, 2026 13:30 View deployment

healeycodes enabled auto-merge (squash) April 7, 2026 13:30

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d8db542

vercel Bot deployed to Preview April 7, 2026 13:34 View deployment

ofhouse approved these changes Apr 7, 2026

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healeycodes merged commit a80217a into main Apr 7, 2026
338 of 340 checks passed

healeycodes deleted the finalize-func-idea branch April 7, 2026 14:19

vercel-cli-release-bot mentioned this pull request Apr 7, 2026

Version Packages #15842

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healeycodes mentioned this pull request Apr 9, 2026

[build-utils] Update zipPath type to support existing callers #15887

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[build-utils] Extend finalizeLambda with pluggable ZIP strategy and pre-digest validation hook#15856

[build-utils] Extend finalizeLambda with pluggable ZIP strategy and pre-digest validation hook#15856
healeycodes merged 2 commits into
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healeycodes commented Apr 7, 2026

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