Extension's $connect method is not used by Prisma query methods unless it's invoked explicitly

[nicolo-tito]

Bug description

When using a Prisma extension with a client $connect method, this is not invoked by the automatic connection of query methods (findFirst, findMany etc...).
It is invoked only by explicitly calling prismaExtension.$connect().

How to reproduce

const prisma = new PrismaClient()

const prismaExtension = prisma.$extends({
  client: {
    async $connect() {
      console.warn('Connecting to database')
      await prisma.$connect()
    }
  }
})

prismaExtension.user.findFirst() // Won't log 'Connecting to database'
// prismaExtension.$connect() // Will log 'Connecting to database'

Expected behavior

Prisma query methods should use the provided extension $connect method on automatic connection

Prisma information

const prisma = new PrismaClient()

const prismaExtension = prisma.$extends({
  client: {
    async $connect() {
      console.warn('Connecting to database')
      await prisma.$connect()
    }
  }
})

prismaExtension.user.findFirst() // Won't log 'Connecting to database'
// prismaExtension.$connect() // Will log 'Connecting to database'

Environment & setup

Operating System:
Platform: win32
Arch: x64
Version: Windows 11 Pro
Binaries:
Node: 20.11.0
npm: N/A
Yarn: N/A
pnpm: N/A
Relevant Packages:
next: 14.1.0
react: 18.2.0
react-dom: 18.2.0
typescript: 5.3.3
Next.js Config:
output: standalone
Database: SQL Server

Prisma Version

5.9.1

[SevInf]

This is generally true for non-extended $connect too - executing request will establish the connection to the database, but it will not do so by calling the same public $connect method. What is a usecase for overriding $connect? Generally, client extensions are meant for additions on top of public client API, not for altering internal behaviours.

[nicolo-tito]

In my case, I was just testing more effective ways to send connection exceptions to a logging service, which in the end I did by just leveraging the $on error event.
I opened the bug anyway because I noticed some official Prisma extensions do override $connect in some cases (e.g. https://github.com/prisma/extension-read-replicas).