Bug description

Starting after I upgraded to 6.17.0, I have a model that looks like

model Location {
  id        String                    @id @default(cuid())
  name      String
  location  Unsupported("geography")?
}

prisma migrate diff --from-schema-datasource prisma/schema.prisma --to-schema-datamodel prisma/schema.prisma

reports

[*] Changed the `Location` table
  [*] Altered column `location` (type changed)

prisma migrate dev

does

You are about to alter the column `location` on the `Location` table, which contains 10 non-null values. The data in that column will be cast from `geography` to `Unsupported("geography")`.

Severity

⚠️ Major: Breaks core functionality (e.g., migrations fail)

Reproduction

Expected vs. Actual Behavior

no migrate diff

Frequency

Consistently reproducible

Does this occur in development or production?

Only in development (e.g., CLI tools, migrations, Prisma Studio)

Is this a regression?

yes, working in 6.16.3, broken in 6.17.0

Workaround

downgrading

Prisma Schema & Queries

// Add relevant schema.prisma snippet

// Add relevant Prisma Client query

Prisma Config

// Add your `prisma.config.ts`

Logs & Debug Info

// Debug logs here

Environment & Setup

Mac OS X, Postgresql

Prisma Version

6.17.0