Postgres Migration Bug after making schema changes (P3006 Error)

Bug description

Migrations don’t appear to be working as expected when using postgresql (tried on both 12.6 and 13). Specifically, running the first migration works fine. However, when I make new changes to the schema.prisma file, Prisma doesn’t pick up on the changes and it instead tries reapplying the migration already there and I get a P3006 error stating the relations are already created.

How to reproduce

1. Set up some temp postgres DB using 12.6 or 13
2. Start with boilerplate prisma schema code
3. Run first migration npx prisma migrate dev --name init --preview-feature
4. Make some change to the prisma.schema file (add new model, change a column name, etc)
5. Run migration again: npx prisma migrate dev --name change --preview-feature

Console Error

Error: P3006

Migration `20210217161456_init` failed to apply cleanly to a temporary database. 
Error:
Database error: Error querying the database: db error: ERROR: relation "User" already exists
   0: sql_migration_connector::flavour::postgres::sql_schema_from_migration_history
             at migration-engine/connectors/sql-migration-connector/src/flavour/postgres.rs:270
   1: sql_migration_connector::sql_database_migration_inferrer::calculate_drift
             at migration-engine/connectors/sql-migration-connector/src/sql_database_migration_inferrer.rs:40
   2: migration_core::api::DevDiagnostic
             at migration-engine/core/src/api.rs:79

Expected behavior

I expected Prisma to generate a new migration file with the new name based on the diff and apply the changes from the diff.

Prisma information

This issue can be reproduced using the simple boilerplate prisma schema.

Schema for 1st Migration

datasource db {
  url           = env("DATABASE_URL")
  provider = "postgresql"
}
generator client {
  provider = "prisma-client-js"
}
model User {
  id        Int      @id @default(autoincrement())
  createdAt DateTime @default(now())
  email     String   @unique
  name      String?  
}

Altered Schema for 2nd Migration

datasource db {
  url      = env("DATABASE_URL")
  provider = "postgresql"
}
generator client {
  provider = "prisma-client-js"
}
model User {
  id        Int      @id @default(autoincrement())
  createdAt DateTime @default(now())
  email     String   @unique
  name      String?
}
// CHANGED: Added new table to DB
model Post {
  id        Int      @id @default(autoincrement())
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt
  published Boolean  @default(false)
  title     String   @db.VarChar(255)
  author    User?    @relation(fields: [authorId], references: [id])
  authorId  Int?
}

Environment & setup

• OS: MacOS
• Database: PostgreSQL (12.6 and 13)
• Node.js version: v14.1.1
• Prisma version: 2.17

[tomhoule]

@chelog last update — I have a PR here, it does look like we broke the MySQL case sensitivity setting detection recently, and didn’t notice because we don’t run CI on windows MySQL installations.

[jbroomer]

I think it may have been a DB permissions issue for me. I had some others try it out and they were able to perform the 2nd migration. It, also, worked when I specified a shadow DB (even though I shouldn’t have had to since I was running locally with a superuser).

Thank you for looking into this though!