Function runtime error: Cannot find module

[dglazkov]

Here's the minimal repro: https://github.com/dglazkov/vercel-test

1. Create a Vercel project
2. Deploy the github project above in it
3. Go to <deployment url>/api/hello.

It gets a consistent "This Serverless Function has crashed." error. When I look into the runtime logs, I see that the the problem is described as follows:

Error: Cannot find module '/var/task/node_modules/@google-labs/breadboard/dist/src/remote.js' imported from /var/task/node_modules/@google-labs/breadboard/dist/src/runner.js
at finalizeResolution (node:internal/modules/esm/resolve:269:11)
at moduleResolve (node:internal/modules/esm/resolve:937:10)
at moduleResolveWithNodePath (node:internal/modules/esm/resolve:1161:14)
at defaultResolve (node:internal/modules/esm/resolve:1204:79)
at ModuleLoader.defaultResolve (node:internal/modules/esm/loader:390:12)
at ModuleLoader.resolve (node:internal/modules/esm/loader:359:25)
at ModuleLoader.getModuleJob (node:internal/modules/esm/loader:234:38)
at ModuleWrap.<anonymous> (node:internal/modules/esm/module_job:87:39)
at link (node:internal/modules/esm/module_job:86:36) {
code: 'ERR_MODULE_NOT_FOUND',
url: 'file:///var/task/node_modules/@google-labs/breadboard/dist/src/remote.js'
}
Node.js process exited with exit status: 1. The logs above can help with debugging the issue.
INIT_REPORT Init Duration: 241.97 ms	Phase: invoke	Status: error	Error Type: Runtime.ExitError
Unknown application error occurred

When I look at the node_modules in the project, the remote.js file is present:

$ find node_modules | grep remote.js    
node_modules/@google-labs/breadboard/dist/src/remote.js
node_modules/@google-labs/breadboard/dist/src/remote.js.map
$

However, when I do a local vercel build, I can see that this file is not present in the node_modules of the function:

$ find .vercel/output/functions/api/hello.func/node_modules | grep "remote.js" 
$

It looks like it's getting dropped somehow? Not sure where. I gave the @vercel/node a quick spelunk and couldn't find anything that jumped out at me.

[dglazkov]

Can confirm it works with VERCEL_CLI_VERSION = vercel@34.2 set.

[onsclom]

@dglazkov v34.2 just shipped as the default, so you can remove this env var now. Thanks for the great description and repro!