Versions

• NodeJS: 23.3.0
• mongodb-memory-server-*: 9.x, 10.x, 10.1.3
• mongodb(the binary version): not relevant, quickest to notice is 7.0.14
• mongodb(the js package): not relevant
• system: linux, but likely others

package: mongo-memory-server-core

What is the Problem?

It seems like when we do child_process.fork now, it implies --import PRELOAD if the original process has been started with --import, like in the following example.
This causes the PRELOAD to be re-executed upon forking to the killer_script, causing a infinite loop of starting and never cleaning-up extra mongo servers.

see #907 (comment)

Code Example

// setup.js
const t = require("node:test");
const { MongoMemoryServer } = require("mongodb-memory-server-core");

let dbServer;

module.exports.connect = async () => {
  dbServer = await MongoMemoryServer.create();
};

module.exports.closeDatabase = async () => {
  await new Promise((res) => {
    setTimeout(res, 1000 * 10);
  })
  await dbServer.stop({ doCleanup: true });
};

t.before(async () => {
  await module.exports.connect();
});

t.after(async () => {
  await module.exports.closeDatabase();
});

// a.test.js
const t = require("node:test");

t.describe("name", () => {
  t.it("test", () => {
    1+1
  });
});

Execute with:

node --test --import ./setup.js

Debug Output

no output by default as we disable stdio for the forked process

Do you know why it happenes?

Yes, as described above.