Float cause duplicate alter table in all migrations

[ingbond]

Bug description

I have such model

model Logbook {
  meter    Float?          @db.Float
  interval Float?          @db.Float
}

After I added these float fields, all my future migrations contains 'ALTER TABLE' for that:

ALTER TABLE [dbo].[Logbook] ALTER COLUMN [meter] FLOAT NULL;
ALTER TABLE [dbo].[Logbook] ALTER COLUMN [interval] FLOAT NULL;

How to reproduce

1. Use sql server
2. Add float fields to your model
3. Create migration

Expected behavior

Do change table only once

Prisma information

model Logbook {
  id             String          @id(map: "PK_Logbook") @default(uuid()) @db.UniqueIdentifier
  title          String          @db.NVarChar(50)
  description    String?          @db.NVarChar(Max)
  meter          Float?          @db.Float
  interval       Float?          @db.Float
  date           DateTime        @db.Date()
  modified       DateTime        @default(now()) @db.DateTime()
}

Environment & setup

OS: Windows
Database: Sql Server
Node.js version: 16.15.1

Prisma Version

3.15.1

[tomhoule]

I could reproduce the problem in tests and identified the cause — it will be fixed by prisma/prisma-engines#3066, which will be in the next Prisma release (4.1). As a workaround in the meantime, you can replace @db.Float with @db.Float(53) to avoid the spurious migrations. Thanks for reporting this bug!