[build-utils] Extract core deserialization funcs by healeycodes · Pull Request #15961 · vercel/vercel

healeycodes · 2026-04-15T08:29:10Z

Extract 6 deserialization functions from the build pipeline into build-utils so they can be called in multiple places (we're trying to reduce code drift).

Also extract shared types.

deserializeLambda supports constructor injection (LambdaClass/NodejsLambdaClass options) so both existing callers can pass their extended Lambda classes with extra properties.

Add mime-types@2.1.28 (matches existing callers).

Importing this code for the two existing callers later on should not introduce semantic changes (and the diffs should be simple to review).

changeset-bot · 2026-04-15T08:29:19Z

🦋 Changeset detected

Latest commit: 4910aec

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

Not sure what this means? Click here to learn what changesets are.

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github-actions · 2026-04-15T08:29:30Z

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vercel · 2026-04-15T08:30:01Z

Low Risk — New utility exports in shared package — additive functions with no behavioral changes to existing code.

packages/build-utils/src/index.ts: exports 6 new deserialization/validation functions and types
packages/build-utils/src/deserialize/: adds deserializeLambda, deserializeEdgeFunction, and serialized type definitions
packages/build-utils/package.json: adds mime-types@2.1.28 dependency

^{Assessed at 4910aec.}

github-actions · 2026-04-15T08:33:07Z

🧪 Unit Test Strategy

Comparing: 1056be9 → 4910aec (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@13.16.0 ### Minor Changes - Add shared deserialization and build-result collection utilities. ([#15961](#15961)) - Add root to experimentalServices to set a service's working directory. ([#15929](#15929)) - Add a new flag to vercel deploy to let users deploy to hive ([#15892](#15892)) ## vercel@51.3.0 ### Minor Changes - Add `vercel alerts inspect` to fetch a single alert group by id with linked project, explicit `--project`, or `--all` scope. ([#15850](#15850)) - Add root to experimentalServices to set a service's working directory. ([#15929](#15929)) - Add a new flag to vercel deploy to let users deploy to hive ([#15892](#15892)) ### Patch Changes - Return 3xx responses directly in `client.fetch()` when `redirect: 'manual'` is passed, instead of entering the error/retry path. ([#15953](#15953)) - Add JSON feature flag support to the CLI so flags can be created, updated, listed, inspected, and set with JSON variant values just like existing boolean, string, and number kinds. ([#15741](#15741)) This aligns the CLI with the recent API and dashboard changes for `json` flags, including parsing raw JSON inputs and preserving structured values in output. - Display case-insensitive feature flag rule comparisons correctly in the CLI. ([#15743](#15743)) - Updated dependencies \[[`86d1f5b3cbd520af2632d4a3d6a1f24557448c0e`](86d1f5b), [`1056be976b6ba9b42cc1e2ffe895d255ab6c9850`](1056be9), [`c27eedaa1b0e3f6e3770b578f62e5463d82f06e0`](c27eeda)]: - @vercel/build-utils@13.16.0 - @vercel/python@6.32.0 - @vercel/backends@0.0.61 - @vercel/elysia@0.1.64 - @vercel/express@0.1.74 - @vercel/fastify@0.1.67 - @vercel/go@3.5.0 - @vercel/h3@0.1.73 - @vercel/hono@0.2.67 - @vercel/hydrogen@1.3.6 - @vercel/koa@0.1.47 - @vercel/nestjs@0.2.68 - @vercel/next@4.16.7 - @vercel/node@5.7.6 - @vercel/redwood@2.4.12 - @vercel/remix-builder@5.7.2 - @vercel/ruby@2.3.2 - @vercel/rust@1.1.0 - @vercel/static-build@2.9.14 ## @vercel/config@0.2.0 ### Minor Changes - Add root to experimentalServices to set a service's working directory. ([#15929](#15929)) ## @vercel/fs-detectors@5.17.0 ### Minor Changes - Add root to experimentalServices to set a service's working directory. ([#15929](#15929)) ### Patch Changes - fix(node): scope entrypoint filter to `api/` directory only ([#15954](#15954)) - Add actix framework preset ([#15752](#15752)) - Updated dependencies \[[`86d1f5b3cbd520af2632d4a3d6a1f24557448c0e`](86d1f5b), [`1056be976b6ba9b42cc1e2ffe895d255ab6c9850`](1056be9), [`620c42ffa6d335c9a6e3e57a1e81c522696b7c2c`](620c42f), [`c27eedaa1b0e3f6e3770b578f62e5463d82f06e0`](c27eeda)]: - @vercel/build-utils@13.16.0 - @vercel/frameworks@3.24.1 ## @vercel/python@6.32.0 ### Minor Changes - Add a new flag to vercel deploy to let users deploy to hive ([#15892](#15892)) ## @vercel/backends@0.0.61 ### Patch Changes - Updated dependencies \[[`86d1f5b3cbd520af2632d4a3d6a1f24557448c0e`](86d1f5b), [`1056be976b6ba9b42cc1e2ffe895d255ab6c9850`](1056be9), [`c27eedaa1b0e3f6e3770b578f62e5463d82f06e0`](c27eeda)]: - @vercel/build-utils@13.16.0 ## @vercel/cervel@0.0.48 ### Patch Changes - Updated dependencies \[]: - @vercel/backends@0.0.61 ## @vercel/client@17.3.3 ### Patch Changes - Updated dependencies \[[`86d1f5b3cbd520af2632d4a3d6a1f24557448c0e`](86d1f5b), [`1056be976b6ba9b42cc1e2ffe895d255ab6c9850`](1056be9), [`c27eedaa1b0e3f6e3770b578f62e5463d82f06e0`](c27eeda)]: - @vercel/build-utils@13.16.0 ## @vercel/elysia@0.1.64 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.6 ## @vercel/express@0.1.74 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.6 - @vercel/cervel@0.0.48 ## @vercel/fastify@0.1.67 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.6 ## @vercel/frameworks@3.24.1 ### Patch Changes - Add actix framework preset ([#15752](#15752)) ## @vercel/gatsby-plugin-vercel-builder@2.1.14 ### Patch Changes - Updated dependencies \[[`86d1f5b3cbd520af2632d4a3d6a1f24557448c0e`](86d1f5b), [`1056be976b6ba9b42cc1e2ffe895d255ab6c9850`](1056be9), [`c27eedaa1b0e3f6e3770b578f62e5463d82f06e0`](c27eeda)]: - @vercel/build-utils@13.16.0 ## @vercel/h3@0.1.73 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.6 ## @vercel/hono@0.2.67 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.6 ## @vercel/koa@0.1.47 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.6 ## @vercel/nestjs@0.2.68 ### Patch Changes - Updated dependencies \[]: - @vercel/node@5.7.6 ## @vercel/node@5.7.6 ### Patch Changes - Updated dependencies \[[`86d1f5b3cbd520af2632d4a3d6a1f24557448c0e`](86d1f5b), [`1056be976b6ba9b42cc1e2ffe895d255ab6c9850`](1056be9), [`c27eedaa1b0e3f6e3770b578f62e5463d82f06e0`](c27eeda)]: - @vercel/build-utils@13.16.0 ## @vercel/static-build@2.9.14 ### Patch Changes - Updated dependencies \[]: - @vercel/gatsby-plugin-vercel-builder@2.1.14 Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

While I was integrating #15961 for existing callers, I saw that we are slightly changing the behavior of prerenders. This PR fixes the differing semantics and unblocks this migration work.

Building on previous PRs: - #15927 - #15961 - #16002 We are extracting the core `deserialize-build-output.ts` file here. This is following refactor efforts in the existing caller codebases to make this extraction simpler. After shipping this extraction, we'll delete the duplicated code and import `deserializeBuildOutput` from this PR. Doing this should introduce zero semantic changes for those callers. Note: callers must inject their own `groupLambdas` strategy. Note2: some existing TODO comments have been left in-place as code documentation.

[build-utils] Extract core deserialization funcs

799cee9

healeycodes requested a review from ofhouse April 15, 2026 08:29

healeycodes requested a review from a team as a code owner April 15, 2026 08:29

ofhouse approved these changes Apr 15, 2026

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4910aec

vercel Bot deployed to Preview April 15, 2026 09:03 View deployment

healeycodes merged commit 86d1f5b into main Apr 15, 2026
202 checks passed

healeycodes deleted the more-deserialize-funcs branch April 15, 2026 12:52

vercel-cli-release-bot mentioned this pull request Apr 15, 2026

Version Packages #15939

Merged

healeycodes mentioned this pull request Apr 16, 2026

[build-utils] Align deserialize logic with existing callers #16002

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healeycodes mentioned this pull request Apr 20, 2026

[build-utils] Extract main deserialize-build-output file #16048

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[build-utils] Extract core deserialization funcs#15961

[build-utils] Extract core deserialization funcs#15961
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