Middleware + $transactions do not play well together

[sdnts]

Bug description

If I use a middleware to Client, then call a prisma.$transaction, then the middleware blocks query execution.

How to reproduce

Assume this schema:

model User {
  id Int @id
  name String
}

I have a middlware that modifies Client responses to also include some extra parameters with it:

const prisma = new PrismaClient();

prisma.$use(async (params, next) => {
  let response = await next(params);
  console.log("middleware", response);
  return {
    params,
    response,
  };
});

  await prisma.$transaction([
    prisma.user.create({
      data: {
        id: "1",
        name: "Sid",
      },
    }),
  ]);

However:

1. The query doesn't get executed. I don't see this record in my database.
2. Instead of logging the Client response, the variabke response seems to be an async function. If I log response.toString(), it looks like calling next returns the actual next function. If I call this returned value again, like so:

prisma.$use(async (params, next) => {
  let response = await next(params);
  response = await (response as any)(params);
  console.log("middleware", response);
  return {
    params,
    response,
  };
});

  await prisma.$transaction([
    prisma.user.create({
      data: {
        id: "1",
        name: "Sid",
        age: 0,
      },
    }),
  ])

then everything works as expected. I see the correct log and the query gets executed.

Expected behavior

No response

Prisma information

model User {
id Int @id
name String
}

Environment & setup

• OS: macOS
• Database: Postgres
• Node.js version: v14.17.0

Prisma Version

This seems to only be happening on dev. Prisma 2.24.1 behaves as expected.

I'm on:

prisma               : 2.25.0-dev.31
@prisma/client       : 2.25.0-dev.31
Current platform     : darwin
Query Engine         : query-engine 89926e7ecbebb89657ae2b56ab3454364ad7b5c5 (at node_modules/@prisma/engines/query-engine-darwin)
Migration Engine     : migration-engine-cli 89926e7ecbebb89657ae2b56ab3454364ad7b5c5 (at node_modules/@prisma/engines/migration-engine-darwin)
Introspection Engine : introspection-core 89926e7ecbebb89657ae2b56ab3454364ad7b5c5 (at node_modules/@prisma/engines/introspection-engine-darwin)
Format Binary        : prisma-fmt 89926e7ecbebb89657ae2b56ab3454364ad7b5c5 (at node_modules/@prisma/engines/prisma-fmt-darwin)
Default Engines Hash : 89926e7ecbebb89657ae2b56ab3454364ad7b5c5
Studio               : 0.399.0

Internal Slack https://prisma-company.slack.com/archives/C016KUHB1R6/p1623327462109600

[pantharshit00]

I can confirm this regression. In 2.25.0-dev.32 it also throws response is not a function which is also odd.

❯ yarn start
yarn run v1.22.5
$ ts-node main.ts
middleware { id: 1, name: 'Sid' }
(node:24744) UnhandledPromiseRejectionWarning: TypeError: response is not a function
    at C:\Users\harshit\code\reproductions\issue-7584\main.ts:8:23
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
    at main (C:\Users\harshit\code\reproductions\issue-7584\main.ts:24:16)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:24744) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handl
ed with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id:
1)(node:24744) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
Terminate batch job (Y/N)?
^C

It doesn't happen in 2.24.1