Some mocked methods no longer work after upgrading to Prisma 6.16 with rust-free engine and prisma-client

[keyserj]

Problem

After upgrading from prisma 5.15.1 -> 6.16.2 and using the rust-free engine + generating prisma code outside of node modules, my tests started failing for multiple mock-related reasons, one specific example being that create would return exactly the model that I passed in, without setting any default values e.g. the primary key.

Previous mocking strategy, using vitest:

import { PrismockClient } from "prismock";
import { PrismockClientType } from "prismock/build/main/lib/client";
import { vi } from "vitest";

vi.mock("@prisma/client", () => ({
  PrismaClient: PrismockClient,
}));

Prisma generator config:

generator client {
  provider            = "prisma-client"
  output              = "./generated/prisma"
  importFileExtension = "ts"
  engineType          = "client"
}

Investigation

I noticed that prismock relies on Prisma.dmmf for determining how to handle each field on creation (and for other mocked methods), but this property is not set with the same values as before the upgrade.

When using prisma-client-js as the client, the values are as follows:

Prisma.dmmf.datamodel.models[0].fields[0], on 5.15.1:

  {
    name: 'id',
    kind: 'scalar',
    isList: false,
    isRequired: true,
    isUnique: false,
    isId: true,
    isReadOnly: false,
    hasDefaultValue: true,
    type: 'Int',
    default: { name: 'autoincrement', args: [] },
    isGenerated: false,
    isUpdatedAt: false
  }

on 6.16.2:

  { name: 'id', kind: 'scalar', type: 'Int' }

I also tried using prisma-client, but this doesn't set Prisma.dmmf at all anymore.

Workaround

This is what is working for me now, getting prismock the dmmf it needs via Prisma's getDMMF(), and prismock's createPrismock:

import { type DMMF } from "@prisma/client/runtime/client";
import { getDMMF } from "@prisma/internals";
import { type PrismockClientType, createPrismock } from "prismock/build/main/lib/client";
import { vi } from "vitest";
import { type PrismaClient } from "@/db/generated/prisma/client";

vi.mock("@/db/generated/prisma/client", async (importOriginal) => {
  const original = await importOriginal<typeof import("@/db/generated/prisma/client")>();
  const { Prisma } = original;

  const dmmf = await getDMMF({ datamodelPath: "./src/db/schema.prisma" });
  const PrismaWithDMMF = { ...Prisma, dmmf };

  return {
    // ensure other parts of the import are still usable e.g. `Prisma`
    ...original,
    PrismaClient: createPrismock(
      PrismaWithDMMF as unknown as typeof Prisma & { dmmf: DMMF.Document },
    ),
  };
});

Notes:

• apparently getDMMF() might be more stable than Prisma.dmmf ? https://www.answeroverflow.com/m/1366812800663420978
• I saw that other people were having issues with a custom directory + createPrismock (Custom client path still attempts to import @prisma/client #1284) but I didn't seem to have that issue

Solution ?

It seems like prismock could rely on getDMMF() instead of Prisma.dmmf. Might need to require a schema path passed in? Not sure if there's a way to get at the configured schema path from Prisma.

[keyserj]

More issues after upgrading to Prisma 7. getDMMF from my workaround above slightly changed, so we have to read the schema ourselves now:

import fs from "node:fs";
...
const schemaContent = fs.readFileSync("./src/db/schema.prisma", "utf-8");
const dmmf = await getDMMF({ datamodel: schemaContent });

And I guess Prisma 7 moved the client path. AI generated this which seems to work (sorry):

vi.hoisted(() => {
  const NodeModule = require("node:module") as typeof import("node:module");
  const nodePath = require("node:path") as typeof import("node:path");

  const originalRequire = NodeModule.prototype.require;

  NodeModule.prototype.require = function patchedRequire(
    this: NodeJS.Module,
    id: string,
  ): NodeJS.Module {
    if (id === "@prisma/client/runtime/library") {
      const redirectPath = nodePath.resolve(
        process.cwd(),
        "node_modules/@prisma/client/runtime/client.js",
      );
      return originalRequire.call(this, redirectPath);
    }
    return originalRequire.call(this, id);
  } as NodeJS.Require;
});