newly built go functions suddenly panic'ing

[zhammer (Zach Hammer)]

suddenly my go functions are crashing with the following:

panic: no such file or directory
goroutine 1 [running]:
main.checkForLambdaWrapper()
/vercel/path0/main__vc__go__.go:24 +0x14a
main.main()
/vercel/path0/main__vc__go__.go:29 +0x13

this is only on new builds. (for some context, this seems to be happening right around when i switched my default branch from master→main

here’s an example of a redeployment where this fails:

deployment: QdayQv6kf (1/17/26)

build logs

22:15:16.889 Running build in Washington, D.C., USA (East) – iad1
22:15:16.890 Build machine configuration: 2 cores, 8 GB
22:15:17.075 Cloning github.com/zhammer/scribly (Branch: master, Commit: 8cbfcab)
22:15:17.475 Cloning completed: 400.000ms
22:15:18.686 Restored build cache from previous deployment (8REKU17wmseUGCVqoR4EoWHofgjf)
22:15:19.116 Running "vercel build"
22:15:20.043 Vercel CLI 50.4.4
22:15:21.118 go: finding module for package github.com/vercel/go-bridge/go/bridge
22:15:21.322 go: found github.com/vercel/go-bridge/go/bridge in github.com/vercel/go-bridge v0.0.0-20221108222652-296f4c6bdb6d
22:15:21.331 go: finding module for package github.com/aws/aws-lambda-go/lambda
22:15:21.332 go: finding module for package github.com/aws/aws-lambda-go/events
22:15:21.416 go: found github.com/aws/aws-lambda-go/events in github.com/aws/aws-lambda-go v1.52.0
22:15:21.417 go: found github.com/aws/aws-lambda-go/lambda in github.com/aws/aws-lambda-go v1.52.0
22:15:23.498 Build Completed in /vercel/output [3s]
22:15:23.541 Deploying outputs...
22:15:29.415 Deployment completed
22:15:30.311 Creating build cache...
22:15:49.969 Created build cache: 19.658s
22:15:49.971 Uploading build cache [203.00 MB]
22:15:52.491 Build cache uploaded: 2.520s

deployment: BBuKZCSgm [redeployment of QdayQv6kf] (1/22/26)

build logs

15:06:05.867 Running build in Washington, D.C., USA (East) – iad1
15:06:05.868 Build machine configuration: 2 cores, 8 GB
15:06:05.878 Cloning github.com/zhammer/scribly (Branch: master, Commit: 8cbfcab)
15:06:05.879 Skipping build cache, deployment was triggered without cache.
15:06:06.186 Cloning completed: 308.000ms
15:06:06.685 Running "vercel build"
15:06:08.624 Vercel CLI 50.4.9
15:06:08.831 Downloading go: https://dl.google.com/go/go1.24.1.linux-amd64.tar.gz
15:06:31.608 go: downloading github.com/kelseyhightower/envconfig v1.4.0
15:06:31.614 go: downloading github.com/jackc/pgx/v5 v5.7.2
15:06:31.730 go: downloading github.com/uptrace/bun v1.2.9
15:06:31.730 go: downloading github.com/uptrace/bun/dialect/pgdialect v1.2.9
15:06:32.029 go: downloading github.com/uptrace/bun/extra/bundebug v1.2.9
15:06:32.366 go: downloading github.com/gorilla/mux v1.8.1
15:06:32.377 go: downloading github.com/gorilla/schema v1.4.1
15:06:32.386 go: downloading github.com/gorilla/sessions v1.4.0
15:06:32.393 go: downloading github.com/mitchellh/mapstructure v1.5.0
15:06:32.404 go: downloading github.com/mssola/useragent v1.0.0
15:06:32.418 go: downloading github.com/stretchr/testify v1.10.0
15:06:32.458 go: downloading github.com/vanng822/go-premailer v1.24.0
15:06:32.650 go: downloading github.com/fatih/color v1.18.0
15:06:32.661 go: downloading github.com/gorilla/securecookie v1.1.2
15:06:32.667 go: downloading github.com/davecgh/go-spew v1.1.1
15:06:32.670 go: downloading github.com/pmezard/go-difflib v1.0.0
15:06:32.710 go: downloading github.com/PuerkitoBio/goquery v1.10.2
15:06:32.711 go: downloading github.com/vanng822/css v1.0.1
15:06:32.720 go: downloading golang.org/x/net v0.37.0
15:06:32.742 go: downloading github.com/jackc/pgpassfile v1.0.0
15:06:32.748 go: downloading github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761
15:06:32.757 go: downloading golang.org/x/crypto v0.36.0
15:06:32.947 go: downloading golang.org/x/text v0.23.0
15:06:33.032 go: downloading github.com/jackc/puddle/v2 v2.2.2
15:06:33.041 go: downloading github.com/tmthrgd/go-hex v0.0.0-20190904060850-447a3041c3bc
15:06:33.048 go: downloading github.com/jinzhu/inflection v1.0.0
15:06:33.058 go: downloading github.com/puzpuzpuz/xsync/v3 v3.5.0
15:06:33.165 go: downloading github.com/vmihailenco/msgpack/v5 v5.4.1
15:06:33.180 go: downloading github.com/mattn/go-colorable v0.1.14
15:06:33.190 go: downloading github.com/mattn/go-isatty v0.0.20
15:06:33.197 go: downloading golang.org/x/sys v0.31.0
15:06:33.425 go: downloading github.com/google/gofuzz v1.2.0
15:06:33.437 go: downloading gopkg.in/yaml.v3 v3.0.1
15:06:33.490 go: downloading github.com/gorilla/css v1.0.1
15:06:33.497 go: downloading github.com/andybalholm/cascadia v1.3.3
15:06:33.517 go: downloading golang.org/x/sync v0.12.0
15:06:33.529 go: downloading github.com/vmihailenco/tagparser/v2 v2.0.0
15:06:33.538 go: downloading gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c
15:06:33.587 go: downloading github.com/kr/pretty v0.3.0
15:06:33.605 go: downloading github.com/kr/text v0.2.0
15:06:33.629 go: downloading github.com/rogpeppe/go-internal v1.14.1
15:06:33.696 go: finding module for package github.com/vercel/go-bridge/go/bridge
15:06:33.972 go: downloading github.com/vercel/go-bridge v0.0.0-20221108222652-296f4c6bdb6d
15:06:34.014 go: found github.com/vercel/go-bridge/go/bridge in github.com/vercel/go-bridge v0.0.0-20221108222652-296f4c6bdb6d
15:06:34.020 go: finding module for package github.com/aws/aws-lambda-go/events
15:06:34.021 go: finding module for package github.com/aws/aws-lambda-go/lambda
15:06:34.049 go: downloading github.com/aws/aws-lambda-go v1.52.0
15:06:34.091 go: found github.com/aws/aws-lambda-go/events in github.com/aws/aws-lambda-go v1.52.0
15:06:34.092 go: found github.com/aws/aws-lambda-go/lambda in github.com/aws/aws-lambda-go v1.52.0
15:07:06.007 Build Completed in /vercel/output [57s]
15:07:06.060 Deploying outputs...
15:07:12.150 Deployment completed
15:07:13.064 Creating build cache...
15:07:29.410 Created build cache: 16.339s
15:07:29.411 Uploading build cache [140.24 MB]
15:07:31.430 Build cache uploaded: 2.008s

[system]

There’s another community post with 404 debugging tips that might be helpful. Please give these solutions a try and let us know how it goes.

Debugging 404 Errors

Sometimes things don’t go as expected when deploying a website. If you see a 404 on your site, that means the page or resource couldn’t be found. There are many possible causes, and the absence of something can be tricky debug if you don’t know where to look. Here are some things you can do to find the cause and fix it. Debugging Tips Check the error code If you see a mostly white screen with 404: NOT_FOUND along with a Code and and ID then you can click the blue info box below the error deta…

A human should be around soon to offer more advice. But you can also get helpful information quickly by asking v0.

[zhammer (Zach Hammer)]

the last functioning deploy was 21 hours ago (January 21, 2026 06:58:42 PM ET)

[zhammer (Zach Hammer)]

looks like something similar happened here- Encountering no such file or directory goroutine 1 [running]: main.checkForLambdaWrapper() /vercel/path0/main__vc__go__.go · vercel/community · Discussion #6531 · GitHub

[zhammer (Zach Hammer)]

okay this looks like a regression from something on the vercel side

1. here’s the file where the panic is occuring, there’s a wrapper file expected in the runtime that is loaded as an env var but doesn’t seem to be found at that path - vercel/packages/go/main.go at 3bf2458ad57a795cf6618d329cdfcfa17c753254 · vercel/vercel · GitHub
2. here is a super simple reproduce project: GitHub - zhammer/vercel-go-test
   1. same thing happens when i deploy that hello world golang func:

[luggiluggi]

I have the exact same issue. Any solution?

[xjasonlyu (Jason Lyu)]

yeah, I’m experiencing the same issue:

Fixing /opt/wrapper: does not exist error in Vercel PHP functions

I’m having the same issue for a Go project deployed to Vercel. The same deployment that worked a few days ago can no longer be redeployed successfully. After redeploying, I get the following panic: panic: no such file or directory goroutine 1 [running]: main.checkForLambdaWrapper() ./main__vc__go__.go:24 +0x14a main.main() ./main__vc__go__.go:29 +0x13 So I checked the vercel code, and it looks like Vercel is injecting the AWS_LAMBDA_EXEC_WRAPPER environment variable into the Lambda runtime. …

[zhammer (Zach Hammer)]

@xjasonlyu weirdly it says your post was flagged by the community and hidden but clicking on your profile led me to Fixing /opt/wrapper: does not exist error in Vercel PHP functions which is helpful so thanks.

[zhammer (Zach Hammer)]

FYI it appears that even with some workarounds to wipe out that broken env var, all user-set env vars (I’m including from integrations here as well) are now absent on functions (e.g. i can’t see a var I set or db credentials from neon)

[swisscdn]

I have the same issue. Started seeing this since yesterday. Build worked but functions crashing.

panic: no such file or directory
goroutine 1 [running]:
main.checkForLambdaWrapper()
/vercel/path0/main__vc__go__.go:24 +0x14a
main.main()
/vercel/path0/main__vc__go__.go:29 +0x13
panic: no such file or directory
goroutine 1 [running]:
main.checkForLambdaWrapper()
/vercel/path0/main__vc__go__.go:24 +0x14a
main.main()
/vercel/path0/main__vc__go__.go:29 +0x13

Then I added a simple function to test, but now build is failing with

failed to `go build`
Error: Command failed: go build -ldflags -s -w -o /tmp/3bc73a02/bootstrap /vercel/path0/main__vc__go__.go

[healeycodes (Andrew Healey)]

This has been resolved as of Friday Jan 23 at 21:42 UTC. New Go function deployments after that time should work as expected. We’ve added some missing regression tests to prevent similar issues. Sorry for the trouble here.