"The 'path' argument must be of type string. Received undefined" when using next-auth

[zaarheed]

Describe the bug
I initially raised a bug on the next-auth repo here: nextauthjs/next-auth#1311

I am using next-on-netlify with next-auth. I am able to enter my email address at /api/auth/signin, but the following page (/api/auth/signin/email) shows the following runtime error:

{"errorType":"Runtime.UnhandledPromiseRejection","errorMessage":"TypeError [ERR_INVALID_ARG_TYPE]: The \"path\" argument must be of type string. Received undefined","trace":["Runtime.UnhandledPromiseRejection: TypeError [ERR_INVALID_ARG_TYPE]: The \"path\" argument must be of type string. Received undefined","    at process.<anonymous> (/var/runtime/index.js:35:15)","    at process.emit (events.js:314:20)","    at processPromiseRejections (internal/process/promises.js:209:33)","    at processTicksAndRejections (internal/process/task_queues.js:98:32)"]}

The full logs on Netlify show the following:

11:22:40 PM: 2021-02-13T23:22:40.108Z	b4c355c3-801b-4f2e-b1a4-9c1fc1f1ef88	INFO	[request] /api/auth/signin

11:22:40 PM: Duration: 25.63 ms	Memory Usage: 133 MB	Init Duration: 632.42 ms	

11:22:45 PM: 2021-02-13T23:22:45.318Z	754432c8-0294-4ed2-b94e-09ee1c1657bb	INFO	[request] /api/auth/signin/email

11:22:45 PM: 2021-02-13T23:22:45.825Z	754432c8-0294-4ed2-b94e-09ee1c1657bb	WARN	Warning: no saslprep library specified. Passwords will not be sanitized

11:22:46 PM: 2021-02-13T23:22:46.115Z	754432c8-0294-4ed2-b94e-09ee1c1657bb	ERROR	Unhandled Promise Rejection 	{"errorType":"Runtime.UnhandledPromiseRejection","errorMessage":"TypeError [ERR_INVALID_ARG_TYPE]: The \"path\" argument must be of type string. Received undefined","reason":{"errorType":"TypeError","errorMessage":"The \"path\" argument must be of type string. Received undefined","code":"ERR_INVALID_ARG_TYPE","stack":["TypeError [ERR_INVALID_ARG_TYPE]: The \"path\" argument must be of type string. Received undefined","    at validateString (internal/validators.js:120:11)","    at Object.dirname (path.js:1128:5)","    at find_package_json (/var/task/src/nextPage.js:132745:23)","    at find_package_json_with_name (/var/task/src/nextPage.js:132762:20)","    at require_optional (/var/task/src/nextPage.js:132797:13)","    at Object.<anonymous> (/var/task/src/nextPage.js:153355:53)","    at Generator.next (<anonymous>)","    at asyncGeneratorStep (/var/task/src/nextPage.js:153264:103)","    at _next (/var/task/src/nextPage.js:153266:194)","    at processTicksAndRejections (internal/process/task_queues.js:97:5)"]},"promise":{},"stack":["Runtime.UnhandledPromiseRejection: TypeError [ERR_INVALID_ARG_TYPE]: The \"path\" argument must be of type string. Received undefined","    at process.<anonymous> (/var/runtime/index.js:35:15)","    at process.emit (events.js:314:20)","    at processPromiseRejections (internal/process/promises.js:209:33)","    at processTicksAndRejections (internal/process/task_queues.js:98:32)"]}

11:22:46 PM: Duration: 805.37 ms	Memory Usage: 136 MB	

11:22:46 PM: Unknown application error occurred

I can't make much of what's going on, but digging through node_modules it seems the validateString() method mentioned in the logs above belongs to the Next.js library.

Any ideas on whether this is a next issue, next-auth issue, or a next-on-netlify issue?

To Reproduce
Steps to reproduce:

1. Navigate to https://next-on-netlify-auth.netlify.app/api/auth/signin
2. Enter email
3. See error message

The same steps above work without error on localhost (both npm run dev and netlify dev).

Here is a repo with the code: https://github.com/zaarheed/next-on-netlify-auth. Run it locally or deploy to Netlify. Remember to add environment variables in .env (example provided) or in the Netlify dashboard.

Versions

"next": "10.0.6"
"next-auth": "3.4.1"
 "next-on-netlify": "2.8.7"

[lindsaylevine]

@zaarheed hey! thanks so much for providing such a detailed issue. i wish it was enough but unfortunately i need a little bit more. i'd love to help you but don't have the time to set up the env vars that seem to be needed/legitimate in order to exactly repro what you're seeing. if you can provide valid "mock" values for EMAIL_FROM, EMAIL_SERVER_ADDRESS and IDENTITY_DB_URL, i can handle NEXTAUTH_URL and NEXT_PUBLIC_BASE_URL (obv, as they'll be my own site's url). feel free to dm me @levlinds if you want to share your original personal ones with me, but it's not in my scope to navigate around next-auth in order to repro unfortunately :( hope you understand!

[zaarheed]

@lindsaylevine totally understandable. I've DM'd you with all the env vars you need to recreate the issue. Once you're done I'll delete them.

If anyone else needs access to the vars to investigate, feel free to DM at @zaarheed and I'm happy to provide.

Appreciate any insight and guidance on this issue :)

[lindsaylevine]

@zaarheed hello! so i believe this may actually be a next-auth issue after all... but not totally sure next-on-netlify is absolved of all responsibility quite yet. cc @balazsorban44

what i do know is that the root of the issue starts here: https://github.com/nextauthjs/next-auth/blob/82dd6ba3e4ba481c5003c918eb1d2fa95f7d76dd/src/adapters/typeorm/index.js#L101

in the lambda that Next.js generates for your API route /api/auth/next_auth (aka what we host in a netlify function), there's the require_optional call for 'mongodb', which eventually takes us to the line that's failing:

location = path.dirname(location);

id argue that the condition that allows this line to run is a bug (aka } else if (location !== '/') {). this condition will pass when location is undefined, causing path.dirname to error out with the error we're seeing.

that said, i acknowledge this code likely never expected location to be undefined. this is where the fault could be on netlify's side. i'll have to do a bit more digging there to know for sure, but i'm not sure right now why this require_optional logic is necessary. this bug persists even when mongodb is installed as a normal dependency in the project.

[zaarheed]

@lindsaylevine Interesting, thanks for taking a look. It sounds very similar to this issue I saw on the next-auth repo earlier.

[lindsaylevine]

if you include package.json in the list of files that get bundled and deployed and that should resolve the issue - I think there are some old issues (possibly closed now) that cover this.

interesting comment from @iaincollins ... i'm not sure this is a fair expectation? traditionally the package.json is excluded from bundles and publish dirs on purpose 🤔

[lindsaylevine]

@zaarheed hey hey - i hate to send you on a wild goose chase. it's frustrating bouncing between repos, for sure. that said, i don't think there's anything left i can do on netlify's end. this is an issue specifically with next-auth and how next is bundling/generating this lambda representing /api/auth/[...nextauth]. when i log currentModule in the source at this point i get:

this of course means currentModule.filename is undefined, causing location to be undefined. the module value comes from the way this lambda is generated by next.js. i could possibly help you personally with a patch, unrelated to netlify, to unblock you, but i'm not sure what we can do on our end :/. if you wanted to temporarily use patch-package to move forward, let me know, and we can try to figure that out together. yk how to reach me on twitter as well!

if a next or next-auth maintainer can prove past what i've proven that this is in fact netlify specific, i'll be happy to dig deeper into their findings!!

[balazsorban44]

To say something here, I don't like require_optional, and would like to move to something like peerDependenciesMeta. We are also in the process of moving out the adapters into their own packages. (https://github.com/nextauthjs/adapters)

Related issue: nextauthjs/next-auth#1012

[brenelz]

So I think I am having this issue. Does next-auth work on netlify currently?

[zaarheed]

@brenelz not working for me when using Mongo as the database

@lindsaylevine has kindly shown me how to use patch-package to see if that will get me around the issue but I haven’t had a chance to try it yet

[lindsaylevine]

@brenelz yeah, it doesn't work. i think next-auth needs to support serverless environments to be compatible with netlify (see: nextauthjs/next-auth#887 which @zaarheed shared earlier in the thread).

[balazsorban44]

@brenelz not totally sure what you mean by us working on netlify? We try not to specifically code against any platform but we do support all the platforms that can run Next.js correctly.

@lindsaylevine we do support serverless, and it works fine for most of the people. (an example of our effort to support serverless is how we bundle css, see the comments in this file:
https://www.github.com/nextauthjs/next-auth/tree/main/src%2Fcss%2Findex.js)
If you are having issues, please report it under our repository with a complete reproduction, so we can track down the problem.