Unreachable shadowDatabaseUrl leads to confusing output

[janpio]

Bug description

C:\Users\Jan\Documents\throwaway\planetscale>npx prisma migrate dev --create-only
Environment variables loaded from .env
Prisma schema loaded from prisma\schema.prisma
Datasource "db": MySQL database "fk-test2" at "127.0.0.1:3306"

Error: P1001

Can't reach database server at `localhost`:`3333`

Please make sure your database server is running at `localhost`:`3333` which can lead to very confusing debugging sessions.

Note the different ports

How to reproduce

Define schema and env as below, only run the main database but not the shadow database.

Expected behavior

Optimal: Better error message that mentions shadow database.
Pragmatic: Shadow database could also get output line a la Datasource "db": MySQL database "fk-test2" at "127.0.0.1:3306", so error message would just not be a full surprise.

Prisma information

.env

DATABASE_URL="mysql://root:@127.0.0.1:3306/fk-test2"
SHADOW_DATABASE_URL="mysql://root:@localhost:3333/fk-test2"

schema:

datasource db {
  provider          = "mysql"
  url               = env("DATABASE_URL")
  shadowDatabaseUrl = env("SHADOW_DATABASE_URL")
}

Environment & setup

• OS: WIndows
• Database:

Prisma Version

2.23.0

[tomhoule]

I dived into the CLI code to see if we could make it happen easily, and it turns out that the "print database info" functionality in the CLI depends on the DMMF, which is going to be brittle and more involved than it needs to be. This is one more argument for moving this logic into engines (mentioned frequently in the past). I opened and candidated an issue: https://github.com/prisma/migrations-team/issues/246

[do4gr]

Here wrapping the error from the shadowdb to tell the user that that's where it came from this would be much clearer.