DateTime precision loss leads to records being unable to be found

[RobertCraigie]

Bug description

Internally, Prisma truncates DateTime values to 3 decimal places, e.g.

2021-11-17 17:04:56.936198 -> 2021-11-17 17:04:56.936000

This can lead to a bug where records cannot be filtered by a DateTime equals value.

This bug was not caught until now as it does not appear on SQLite but does on PostgreSQL.

How to reproduce

import asyncio
from datetime import datetime
from prisma import Client

async def main() -> None:
    db = Client()
    await db.connect()

    date = datetime.utcnow()
    print(date)

    post = await db.post.create(
        data={
            'title': 'My first post',
            'created_at': date,
        },
    )
    print(post.created_at)

    found = await db.post.find_first(
        where={
            'created_at': date,
        },
    )
    print(f'Post found? {found is not None}')

    await db.disconnect()

if __name__ == '__main__':
    asyncio.get_event_loop().run_until_complete(main())

SQLite output:

2021-11-17 17:13:21.288983 
2021-11-17 17:13:21.288000+00:00 
Post found? True

PostgreSQL output:

2021-11-17 17:14:15.055458 
2021-11-17 17:14:15.055000+00:00 
Post found? False

Expected behavior

PostgreSQL output:

2021-11-17 17:14:15.055458 
2021-11-17 17:14:15.055000+00:00 
Post found? True

Prisma information

datasource client {
  // provider = "sqlite"
  // url      = "file:dev.db"
  provider = "postgres"
  url      = env("DATABASE_URL")
}

generator client {
  provider = "prisma-client-py"
  interface = "asyncio"
}

model Post {
  id         String   @id @default(cuid())
  created_at DateTime @default(now())
  updated_at DateTime @updatedAt
  title      String
  published  Boolean  @default(false)
  desc       String?
}

Environment & setup

• OS: Mac OS
• Database: PostgreSQL
• Python version: Python 3.9.1
• Prisma version:

prisma               : 3.4.0
prisma client python : 0.3.0
platform             : darwin
engines              : 1c9fdaa9e2319b814822d6dbfd0a69e1fcc13a85
install path         : .venv/lib/python3.9/site-packages/prisma
installed extras     : []