[@vercel/backends] Support function overrides by jeffsee55 · Pull Request #15214 · vercel/vercel

jeffsee55 · 2026-02-23T21:06:29Z

Note

Low Risk Change

This PR adds function override support to the backends builder by spreading config overrides into lambda options and removes validation logic for unused functions, which could allow previously flagged configurations to pass silently.

Adds functionConfigOverrides spread into lambda args, allowing external config to override defaults
Removes unused function validation loop for backends, now returns null instead of checking entrypoints
Minor TypeScript version bump in go package (4.3.4 → 4.9.5)

^{Risk assessment for commit 776724b.}

changeset-bot · 2026-02-23T21:06:38Z

🦋 Changeset detected

Latest commit: 776724b

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

This PR includes changesets to release 16 packages

Name	Type
@vercel/fs-detectors	Patch
@vercel/build-utils	Patch
@vercel/backends	Patch
vercel	Patch
@vercel/static-build	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/cervel	Patch

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github-actions · 2026-02-23T21:07:09Z

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github-actions · 2026-02-23T21:10:51Z

🧪 Unit Test Strategy

Comparing: b16548f → 776724b (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

packages/backends/src/index.ts

…ng `functionFailoverRegions` and `experimentalTriggers` properties and doesn't support glob pattern matching for function config keys. This commit fixes the issue reported at packages/backends/src/index.ts:140 ## Bug Analysis The `@vercel/backends` builder implemented a custom `getFunctionConfigOverrides` function to read function configuration from `vercel.json`. This custom function has three problems compared to the established `getLambdaOptionsFromFunction` utility used by all other builders (@vercel/next, @vercel/go, @vercel/rust): 1. **Missing `functionFailoverRegions`**: If a user configures `functionFailoverRegions` in their `vercel.json` for a backends function, the setting is silently ignored. This property controls failover region configuration for Lambda functions. 2. **Missing `experimentalTriggers`**: The `experimentalTriggers` property (used for queue/v2beta triggers) is also not forwarded from the function config. 3. **No glob/minimatch pattern matching**: The custom implementation does a direct property lookup (`args.config.functions?.[dest]`), meaning function config entries using glob patterns (e.g., `"api/**/*.ts"`) won't match. The standard `getLambdaOptionsFromFunction` iterates over all entries and uses `minimatch` for pattern matching. 4. **Maintenance risk**: Any future properties added to `getLambdaOptionsFromFunction` won't be picked up by the custom implementation, leading to recurring inconsistencies. ## Fix Replaced the custom `getFunctionConfigOverrides` inline function with a call to the existing `getLambdaOptionsFromFunction` utility from `@vercel/build-utils`. This: - Adds the `getLambdaOptionsFromFunction` import from `@vercel/build-utils` - Replaces the 10-line custom function and its call with a single `await getLambdaOptionsFromFunction({ sourceFile: entrypoint, config: args.config })` call - Brings `@vercel/backends` in line with all other builders for function config resolution - Automatically includes `functionFailoverRegions`, `experimentalTriggers`, and any future properties - Enables glob pattern matching for function config keys Co-authored-by: Vercel <vercel[bot]@users.noreply.github.com> Co-authored-by: jeffsee55 <jeffsee.55@gmail.com>

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/routing-utils@6.0.0 ### Major Changes - Allow `routes` to coexist with `rewrites`, `headers`, `redirects`, `cleanUrls`, and `trailingSlash`. ([#15020](#15020)) This is part of our efforts to undeprecate `routes`, which had previously been deprecated for a few years and replaced by the properties above. Now that we are undeprecating `routes` in favor of a more focused deprecation of properties within it, it is now allowed to coexist with the new properties. When used together, `routes` are inserted after `cleanUrls` and `trailingSlash` but before `redirects`, `headers`, and `rewrites` in the routing order. - Deprecate `handle`, `important`, and `override` properties in `routes` schema ([#15015](#15015)) ## @vercel/build-utils@13.6.0 ### Minor Changes - Find entrypoints for django projects. ([#15167](#15167)) ### Patch Changes - Rename fetch to nodeFetch in cases where it is an import from node-fetch ([#15234](#15234)) - [@vercel/build-utils] fix uncaught exception in streamToBuffer when stream exceeds max Buffer size ([#15276](#15276)) - Remove source and destination typo suggestions for routes schema ([#15014](#15014)) - Support function overrides in backends builder ([#15214](#15214)) - Updated dependencies \[[`b3a96cc4f276ce8d16c695eabd499d3a17e73aa8`](b3a96cc)]: - @vercel/python-analysis@0.8.0 ## vercel@50.25.0 ### Minor Changes - Launch auto-provision flow as default for `vercel integration add` and `vercel install`. The `FF_AUTO_PROVISION_INSTALL` flag is now a kill-switch (`=0` to revert) instead of opt-in. ([#15265](#15265)) - [services] make the `experimentalServices` config the primary marker for the services flow ([#15246](#15246)) - Added command to fetch a development OIDC token ([#14785](#14785)) ### Patch Changes - Rename fetch to nodeFetch when importing from node-fetch ([#15232](#15232)) - Add setup/destroy hooks and context handling to the CLI eval runner. ([#15247](#15247)) - [services] fix dev server hang when FastAPI CLI is used ([#15274](#15274)) - Fix `--help` flag to return exit code 0 instead of 2 for the `metrics` command, aligning with standard CLI conventions. ([#15259](#15259)) - Rename fetch to nodeFetch in cases where it is an import from node-fetch ([#15234](#15234)) - Change `vercel metrics` default query output from CSV to rich text with metadata, summary tables, sparklines, and optional raw values via `--raw-values`. ([#15178](#15178)) - Removes the legacy SSO redirect flow code. ([#15228](#15228)) - Updated dependencies \[[`ad86425c3e0a1d1738cef8464dd767dd1d9a0e9a`](ad86425), [`3d872692c601abeec98743d2af3a3ea19587e799`](3d87269), [`d9e3a570a9c6ee47afa3446ec611b6a9e4b4feec`](d9e3a57), [`2db57840669ca2fa8dadf492bd38c21bf9e3cfeb`](2db5784), [`0d42acfd22e51e51cb0e4a5aea7c19f3886ed496`](0d42acf), [`8404a7315260851495d708f1c7c6e870d7ffa007`](8404a73), [`fbf649223e6fa8b509295a85784347dcebd4a0b0`](fbf6492), [`b3a96cc4f276ce8d16c695eabd499d3a17e73aa8`](b3a96cc), [`9a6358529f0737415110cf03d626dc9ee8e99126`](9a63585)]: - @vercel/remix-builder@5.6.0 - @vercel/python@6.17.0 - @vercel/next@4.15.35 - @vercel/node@5.6.8 - @vercel/static-build@2.8.42 - @vercel/build-utils@13.6.0 - @vercel/go@3.4.3 - @vercel/backends@0.0.38 - @vercel/elysia@0.1.41 - @vercel/express@0.1.50 - @vercel/fastify@0.1.44 - @vercel/h3@0.1.50 - @vercel/hono@0.2.44 - @vercel/koa@0.1.24 - @vercel/nestjs@0.2.45 - @vercel/redwood@2.4.9 - @vercel/rust@1.0.5 - @vercel/hydrogen@1.3.5 - @vercel/ruby@2.3.2 ## @vercel/python@6.17.0 ### Minor Changes - Find entrypoints for django projects. ([#15167](#15167)) ### Patch Changes - Rename fetch to nodeFetch when importing from node-fetch ([#15232](#15232)) - [services] fix dev server hang when FastAPI CLI is used ([#15274](#15274)) - [python] fix dev server crash on relative imports ([#15269](#15269)) - Updated dependencies \[[`b3a96cc4f276ce8d16c695eabd499d3a17e73aa8`](b3a96cc)]: - @vercel/python-analysis@0.8.0 ## @vercel/python-analysis@0.8.0 ### Minor Changes - Find entrypoints for django projects. ([#15167](#15167)) ## @vercel/remix-builder@5.6.0 ### Minor Changes - [remix] Support future.v8_middleware option ([#15189](#15189)) ## @vercel/backends@0.0.38 ### Patch Changes - Support function overrides in backends builder ([#15214](#15214)) - Updated dependencies \[[`2db57840669ca2fa8dadf492bd38c21bf9e3cfeb`](2db5784), [`0d42acfd22e51e51cb0e4a5aea7c19f3886ed496`](0d42acf), [`8404a7315260851495d708f1c7c6e870d7ffa007`](8404a73), [`b3a96cc4f276ce8d16c695eabd499d3a17e73aa8`](b3a96cc), [`9a6358529f0737415110cf03d626dc9ee8e99126`](9a63585)]: - @vercel/build-utils@13.6.0 ## @vercel/cervel@0.0.25 ### Patch Changes - Updated dependencies \[[`9a6358529f0737415110cf03d626dc9ee8e99126`](9a63585)]: - @vercel/backends@0.0.38 ## @vercel/client@17.2.48 ### Patch Changes - rename fetch to fetchApi ([#15231](#15231)) - Updated dependencies \[[`e64a85daec784b4fe571abe7405a80aca150007a`](e64a85d), [`2db57840669ca2fa8dadf492bd38c21bf9e3cfeb`](2db5784), [`0d42acfd22e51e51cb0e4a5aea7c19f3886ed496`](0d42acf), [`8404a7315260851495d708f1c7c6e870d7ffa007`](8404a73), [`b3a96cc4f276ce8d16c695eabd499d3a17e73aa8`](b3a96cc), [`9a6358529f0737415110cf03d626dc9ee8e99126`](9a63585), [`af6a651229cad4ddb7fcc15bd14d06355c2b77ee`](af6a651)]: - @vercel/routing-utils@6.0.0 - @vercel/build-utils@13.6.0 ## @vercel/config@0.0.35 ### Patch Changes - Updated dependencies \[[`e64a85daec784b4fe571abe7405a80aca150007a`](e64a85d), [`af6a651229cad4ddb7fcc15bd14d06355c2b77ee`](af6a651)]: - @vercel/routing-utils@6.0.0 ## @vercel/elysia@0.1.41 ### Patch Changes - Updated dependencies \[[`3d872692c601abeec98743d2af3a3ea19587e799`](3d87269)]: - @vercel/node@5.6.8 ## @vercel/express@0.1.50 ### Patch Changes - Updated dependencies \[[`3d872692c601abeec98743d2af3a3ea19587e799`](3d87269)]: - @vercel/node@5.6.8 - @vercel/cervel@0.0.25 ## @vercel/fastify@0.1.44 ### Patch Changes - Updated dependencies \[[`3d872692c601abeec98743d2af3a3ea19587e799`](3d87269)]: - @vercel/node@5.6.8 ## @vercel/frameworks@3.19.1 ### Patch Changes - Rename fetch to nodeFetch when importing from node-fetch ([#15232](#15232)) ## @vercel/fs-detectors@5.8.12 ### Patch Changes - Support function overrides in backends builder ([#15214](#15214)) - Updated dependencies \[[`3d872692c601abeec98743d2af3a3ea19587e799`](3d87269), [`e64a85daec784b4fe571abe7405a80aca150007a`](e64a85d), [`af6a651229cad4ddb7fcc15bd14d06355c2b77ee`](af6a651)]: - @vercel/frameworks@3.19.1 - @vercel/routing-utils@6.0.0 ## @vercel/gatsby-plugin-vercel-builder@2.0.140 ### Patch Changes - Updated dependencies \[[`2db57840669ca2fa8dadf492bd38c21bf9e3cfeb`](2db5784), [`0d42acfd22e51e51cb0e4a5aea7c19f3886ed496`](0d42acf), [`8404a7315260851495d708f1c7c6e870d7ffa007`](8404a73), [`b3a96cc4f276ce8d16c695eabd499d3a17e73aa8`](b3a96cc), [`9a6358529f0737415110cf03d626dc9ee8e99126`](9a63585)]: - @vercel/build-utils@13.6.0 ## @vercel/go@3.4.3 ### Patch Changes - Rename fetch to nodeFetch in cases where it is an import from node-fetch ([#15234](#15234)) ## @vercel/h3@0.1.50 ### Patch Changes - Updated dependencies \[[`3d872692c601abeec98743d2af3a3ea19587e799`](3d87269)]: - @vercel/node@5.6.8 ## @vercel/hono@0.2.44 ### Patch Changes - Updated dependencies \[[`3d872692c601abeec98743d2af3a3ea19587e799`](3d87269)]: - @vercel/node@5.6.8 ## @vercel/koa@0.1.24 ### Patch Changes - Updated dependencies \[[`3d872692c601abeec98743d2af3a3ea19587e799`](3d87269)]: - @vercel/node@5.6.8 ## @vercel/nestjs@0.2.45 ### Patch Changes - Updated dependencies \[[`3d872692c601abeec98743d2af3a3ea19587e799`](3d87269)]: - @vercel/node@5.6.8 ## @vercel/next@4.15.35 ### Patch Changes - Rename fetch to nodeFetch when importing from node-fetch ([#15232](#15232)) ## @vercel/node@5.6.8 ### Patch Changes - Rename fetch to nodeFetch when importing from node-fetch ([#15232](#15232)) - Updated dependencies \[[`2db57840669ca2fa8dadf492bd38c21bf9e3cfeb`](2db5784), [`0d42acfd22e51e51cb0e4a5aea7c19f3886ed496`](0d42acf), [`8404a7315260851495d708f1c7c6e870d7ffa007`](8404a73), [`b3a96cc4f276ce8d16c695eabd499d3a17e73aa8`](b3a96cc), [`9a6358529f0737415110cf03d626dc9ee8e99126`](9a63585)]: - @vercel/build-utils@13.6.0 ## @vercel/static-build@2.8.42 ### Patch Changes - Rename fetch to nodeFetch in cases where it is an import from node-fetch ([#15234](#15234)) - Updated dependencies \[]: - @vercel/gatsby-plugin-vercel-builder@2.0.140 ## @vercel/python-runtime@0.5.2 ### Patch Changes - fix ASGI lifecycle events in non-IPC codepath ([#15268](#15268)) ## @vercel/python-workers@0.0.11 ### Patch Changes - Add a version bump for `@vercel/python-workers` so previously merged changes are included in the next release. ([#15254](#15254))  > [!NOTE] > Low Risk Change > > This PR is an automated Changesets release that only updates version numbers in package.json files and CHANGELOG.md files across multiple packages, with no logic or schema changes. > > - Version bumps across ~30 packages (package.json version fields) > - CHANGELOG.md updates documenting previously merged changes > - Deletion of .changeset/*.md files consumed by release automation > > <sup>Risk assessment for [commit 9b78e59](https://github.com/vercel/vercel/commit/9b78e59c7c4716d10beac3a0228e767c8565f65a).</sup>  Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Support function overrides

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jeffsee55 requested review from a team and agadzik as code owners February 23, 2026 21:06

jeffsee55 changed the title ~~Support function overrides~~ [@vercel/backends] Support function overrides Feb 23, 2026

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jeffsee55 requested a review from TooTallNate February 23, 2026 21:33

Merge branch 'main' into backends-func-overrides

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jeffsee55 merged commit 9a63585 into main Feb 25, 2026
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jeffsee55 deleted the backends-func-overrides branch February 25, 2026 16:28

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[@vercel/backends] Support function overrides#15214

[@vercel/backends] Support function overrides#15214
jeffsee55 merged 9 commits intomainfrom
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