Unclear error message when using prisma-level default functions (cuid, uuid) as default for non-nullable fields

Bug description

After adding a NON NULLABLE column with a default value to an existing table with records in the database, I get the following error:

Added the required column `x` to the `y` table without a default value. There are `z` rows in this table, it is not possible to execute this migration.

The model looks like the following:

model MyModel {
    id   String   @default(cuid())             @id
    x    String   @default("Some value")
    // And some other columns...
}

The column causing the error is the x column.

How to reproduce

1. Create a migration with a model and some columns.
2. Add a NON NULLABLE column to that model.
3. Save the changes and run the migration.
4. See error.

Expected behavior

Migration to be successfully applied.

Environment & setup

• OS: Windows 10 2004 (Running on WSL 2)
• Database: PostgreSQL
• Node.js version: 12.18.2
• Prisma version: 2.1.3

[tomhoule]

cuid() and uuid() are not database-level defaults — they are instead populated by the prisma-client. The only workaround in this case is to add the columns as optional, populate them, then make them required. I’ll keep this issue open as a reminder to expand the error message.

[Madmeerkat-creator]

Hi! I had a same problem, having error <Step 1 Added the required column password to the User table without a default value. There are 1 rows in this table, it is not possible to execute this migration.> So I checked my MySQL Workbench and I found that there is a data. So I erased it… and it finally worked! Here is my code

model User {
  id      Int       @default(autoincrement()) @id
  email   String    @unique
  name    String
  password  String
}