[Introspection] Identify Prisma 1 Id defaults

[divyenduz]

Problem

Prisma 1 IDs are introspected as Strings without a default/@default.

Suggested solution

Introspection can be improved following this logic:

1. Is it a Prisma1 or Prisma11 classified database schema?
2. Is there a primary key column of type char(25) or char(36)?
3. If yes, apply the following default:
   • char(25) -> @default(cuid())
   • char(36) -> @default(uuid())

Additional context

• Internal investigation document https://www.notion.so/prismaio/String-IDs-Details-47a2e3f256a848479cc3d34f51e23986
• Related issues that will keep this information on Re-Introspection: [Re-Introspection] Keep defaults that are not persisted in the database (cuid() and uuid()) #2534
• Will close this issue: [Introspection] No @default attribute when introspecting on PostgreSQL from Prisma V1 #1897

[do4gr]

Additionally we should generat warnings for cases where we do such an inference. Since this is based upon us recognizing the schema as P1 migrated and this itself is only a heuristic.

We would therefore render the defaults but emit warnings at the same time, so the user knows these are not based on information in the SQL schema.