nestjs
NestJS 9 with Fastify ignores @Res() in controller
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Is there an existing issue that is already proposing this?
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Potential Commit/PR that introduced the regression
No response
NestJS version
8.4.7 -> 9.1.2
Describe the regression
NestJS appears to be ignoring the use of @Res() to override Nest's standard code for responding to a request, specifically when using Fastify.
In version 8, Nest doesn't attempt to respond to requests at all if it sees @Res() in the controller's parameters and allows you to respond when needed (for example, any asynchronous code not through a Promise). In version 9, the same code will respond immediately, ignoring your res.send if it doesn't happen synchronously.
Note: NestJS 9 using Express behaves the same way as NestJS 8 using Fastify.
Minimum reproduction code
https://github.com/coryroloff/nestjs-res-bug
Input code
No response
Expected behavior
To test NestJS 8, run the following:
cd nestjs-8
npm install
npm run start:dev
curl localhost:3000/test-res-bug -v
You will get the response "hello world" back. This is expected behavior.
To test NestJS 9 with Fastify, run the following:
cd nestjs-9
npm install
npm run start:dev
curl localhost:3000/test-res-bug -v
You will get an empty response body back, instead of the expected "hello world".
To test NestJS 9 with Express, run the following:
cd nestjs-9-express
npm install
npm run start:dev
curl localhost:3000/test-res-bug -v
You will get the response "hello world" back. This is expected behavior.
Other
No response
This actually might be related to something I'm looking into with @fastify/view integration and not being able to res.view() from an exception filter. I think there's somewhere that an await is possibly missing that's causing fastify to send a response before we expect it to. I'll try to update this as I can
Did you have a chance to find the root cause @jmcdo29? Let me know and I can take over if you're busy 🙌
This may be the problem
Did you have a chance to find the root cause @jmcdo29? Let me know and I can take over if you're busy raised_hands
@kamilmysliwiec that might be best. What SirReiva added might be relevant here too
@SirReiva's answer explains and solves the issue I was running into. Thanks, everyone.
making this change apparently works