Type for an enum array is incorrectly generated

[alii]

With postgres as a datasource, prisma will let you use an enum array as a value. Example:

enum UserPermissions {
  FOO
  BAR
}

model User {
  id String @id
  permissions UserPermissions[]
}

Unfortunately prisma-kysely generates the array type that the prisma client would return, but in reality the migration/shape prisma would use for this is actually a string, and it's stored as an arbitrary string format: {FOO,BAR}. An empty array would be stored as the string {}

Of course I wouldn't expect kysely to be selecting this string value as an array, so I think it would make the most sense for prisma-kysely to either say "we don't support enum array types" or (ideally) have it generate this array to a string type.

Here's an example of what we could generate:

export type EnumArrayInner<T extends string, All extends string> = T extends infer Single extends string ? T | `${Single},${Exclude<All, Single>}` : never
export type EnumArray<T extends string> = `{${EnumArrayInner<T, T>}}`;

export const UserPermissions = {
    FOO: "FOO",
    BAR: "BAR"
} as const;
export type UserPermissions = (typeof UserPermissions)[keyof typeof UserPermissions];

export type User = {
    id: string;
    permissions: EnumArray<UserPermissions>;
}

[alii]

I did already open #108 but I noticed a problem in it with the generated TypeScript types. I'm going to have another shot at fixing this next weekend.