fix: propagate generics from FastifyRegister to plugin type

[stefee]

Closes #4032

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[RafaelGSS]

Can you include a tsd test as well?

[stefee]

@RafaelGSS Yep, will do when I have time.

[stefee]

Fixed commit message.

[stefee]

Changing back to a draft - there's a failing test.

[stefee]

The failing test is in hook.test-d.ts

https://github.com/stefee/fastify/blob/e68bd8c42b5cbcabcb4cfee860e1e8d87a730b9c/test/types/hooks.test-d.ts#L217-L236

test/types/hooks.test-d.ts:235:19
  ✖  235:19  No overload matches this call.
  The last overload gave the following error.
    Argument of type "preHandler" is not assignable to parameter of type "onClose".

  1 error

The problem is to do with passing anonymous (and therefore implicitly typed) plugin into .register(. It seems that the type of instance that gets passed to the plugin has a concrete type which has changed as a result of the change in this PR.

[stefee]

The above issue was resolved by providing default values inferred from the instance on which .register is called.

[stefee]

Moved tests into the relevant file.

[RafaelGSS]

LGTM.

[RafaelGSS]

cc: @sinclairzx81

[mcollina]

@climba03003 @fox1t can you take a look?

[climba03003]

I am only afraid will it affect the non-default generic.
For example, people using http2 or https.

[mcollina]

@sinclairzx81 do you approve this?

[sinclairzx81]

@mcollina Hi, this looks ok to me. As suggested by @climba03003, it may be good to put some TS tests up around the http2 and https server types (as these propagate), This would just rule out any issues with varying server types prior to merge if there are concerns there.

But other than that, this looks great :) @stefee Nice work!

[stefee]

@climba03003 @sinclairzx81 @mcollina Which type signature is expected for a https server instance?

default:

FastifyInstance

http2:

FastifyInstance<Http2Server, Http2ServerRequest, Http2ServerResponse>

with type provider:

FastifyInstance<Server, IncomingMessage, ServerResponse, FastifyLoggerInstance, TestTypeProvider>

https: ?

[mcollina]

lgtm

[sinclairzx81]

Which type signature is expected for a https server instance?

@stefee The following generic arguments should match each of the varying server types.

import * as http from 'http'
import * as https from 'https'
import * as http2 from 'http2'

...

// With Http
const serverWithHttp = fastify({ })
type ServerWithHttp = FastifyInstance<http.Server, http.IncomingMessage, http.ServerResponse>

...

// With Https
const serverWithHttps = fastify({ https: { } })
type ServerWithHttps = FastifyInstance<https.Server, http.IncomingMessage, http.ServerResponse>

...

// With Http2
const serverWithHttp2 = fastify({ http2: true })
type ServerWithHttp2 = FastifyInstance<http2.Http2Server, http2.Http2ServerRequest, http2.Http2ServerResponse>
...

Have tested the HTTPS variant locally, and all looks good to me :)

Good work!

[fox1t]

LGTM! Nice job!

[github-actions]

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