Surface schema validation errors during Re-Introspection and change flow

[do4gr]

(Currently Re-Introspection is in an experimental state and has its own flag to be activated.)

The command prisma introspection --experimental-reintrospection just returns a warning when it receives an invalid Prisma schema (that it needs to work its Re-Introspection magic). It then proceeds to run a normal prisma introspection and still delivers a valid schema.

This can be annoying for users with big schemas, that make it hard to pinpoint the reason why the schema is invalid. See #3044 (comment)

We should change this behavior to instead error out and return the validation errors for the invalid schema. Additionally, we should introduce a flag that allows the user to ignore the invalid schema (--clean, --fresh, --force, --overwrite or similar).

This is what this would look like:

CLI Command	Valid Previous Schema	Invalid Previous Schema
prisma introspection --experimental-reintrospection	success, enriched schema based on db state and previous schema	error, list schema validation errors
prisma introspection --experimental-reintrospection --clean	success, raw schema based on db state	success, raw schema based on db state
prisma introspection	success, raw schema based on db state	success, raw schema based on db state

---

After Re-Introspection leaves the experimental state the commands can be collapsed into:

CLI Command	Valid Previous Schema	Invalid Previous Schema
prisma introspection	success, enriched schema based on db state and previous schema	error, list schema validation errors
prisma introspection --clean	success, raw schema based on db state	success, raw schema based on db state

[mavilein]

Internal Note: @do4gr has implemented the engines part. Awaiting integration on CLI side.

[Jolg42]

CLI implementation is done in 2.4.0-dev.30, if everything works as expected this could be closed.

[janpio]

What error message does a user get when the Re-Introspection fails that tells them to use --clean?