This PR adds a feature which fixes another issue with migrations in
Postgres and does few refactors that significantly reduce code
duplication.
Previously, if you needed to use the underlying database directly in
migrations with the active transaction (for example to execute raw SQL),
created from `payload create:migration`, as `req` doesn't work there you
had to do something like this:
```ts
// Postgres
export async function up({ payload, req }: MigrateUpArgs): Promise<void> {
const db = payload.db.sessions?.[await req.transactionID!].db ?? payload.db
const { rows: posts } = await db.execute(sql`SELECT * from posts`)
}
// MongoDB
export async function up({ payload, req }: MigrateUpArgs): Promise<void> {
const session = payload.db.sessions?.[await req.transactionID!]
const posts = await payload.db.collections.posts.collection.find({ session }).toArray()
}
```
Which was:
1. Awkward to write
2. Not documented anywhere
Now, we expose `session` and `db` to `up` and `down` functions for you:
#### MongoDB:
```ts
import { type MigrateUpArgs } from '@payloadcms/db-mongodb'
export async function up({ session, payload, req }: MigrateUpArgs): Promise<void> {
const posts = await payload.db.collections.posts.collection.find({ session }).toArray()
}
```
#### Postgres:
```ts
import { type MigrateUpArgs, sql } from '@payloadcms/db-postgres'
export async function up({ db, payload, req }: MigrateUpArgs): Promise<void> {
const { rows: posts } = await db.execute(sql`SELECT * from posts`)
}
```
#### SQLite:
```ts
import { type MigrateUpArgs, sql } from '@payloadcms/db-sqlite'
export async function up({ db, payload, req }: MigrateUpArgs): Promise<void> {
const { rows: posts } = await db.run(sql`SELECT * from posts`)
}
```
This actually was a thing with Postgres migrations, we already were
passing `db`, but:
1. Only for `up` and when running `payload migrate`, not for example
with `payload migrate:fresh`
2. Not documented neither in TypeScript or docs.
By ensuring we use `db`, this also fixes an issue that affects all
Postgres/SQLite migrations:
Currently, if we run `payload migration:create` with the postgres
adapter we get a file like this:
```ts
import { MigrateUpArgs, MigrateDownArgs, sql } from '@payloadcms/db-postgres'
export async function up({ payload, req }: MigrateUpArgs): Promise<void> {
await payload.db.drizzle.execute(sql`
CREATE TABLE IF NOT EXISTS "users" (
"id" serial PRIMARY KEY NOT NULL,
);
```
Looks good?
Not exactly!
`payload.db.drizzle.execute()` doesn't really use the current
transaction which can lead to some problems.
Instead, it should use the `db` from `payload.db.sessions?.[await
req.transactionID!].db` because that's where we store our Drizzle
instance with the transaction.
But now, if we generate `payload migrate:create` we get:
```ts
import { MigrateUpArgs, MigrateDownArgs, sql } from '@payloadcms/db-postgres'
export async function up({ db, payload, req }: MigrateUpArgs): Promise<void> {
await db.execute(sql`
CREATE TABLE IF NOT EXISTS "users" (
"id" serial PRIMARY KEY NOT NULL,
);
```
Which is what we want, as the `db` is passed correctly here:
76428373e4/packages/drizzle/src/migrate.ts (L88-L90)
```ts
export async function up({ db, payload, req }: MigrateUpArgs): Promise<void> {
const dbWithTransaction = payload.db.sessions?.[await req.transactionID!].db
payload.logger.info({ one: db === dbWithTransaction })
payload.logger.info({ two: db === payload.db.drizzle })
```
<img width="336" alt="image"
src="https://github.com/user-attachments/assets/f9fab5a9-44c2-44a9-95dd-8e5cf267f027">
Additionally, this PR refactors:
* `createMigration` with Drizzle - now we have sharable
`buildCreateMigration` in `@payloadcms/drizzle` to reduce copy-pasting
of the same logic.
* the `v2-v3` relationships migration for Postgres is now shared between
`db-postgres` and `db-vercel-postgres`, again to reduce copy-paste.
b73fc586b8