[Bug]: Direct assignment to array methods creates enumerable properties causing Jest toEqual() failures

[vladlearns]

Version

v1.56.0

Steps to reproduce

The bug is in

playwright/packages/playwright/src/worker/testInfo.ts

Line 216 in 99515d7

this._attachmentsPush = this.attachments.push.bind(this.attachments);

typescriptthis._attachmentsPush = this.attachments.push.bind(this.attachments);
this.attachments.push = (...attachments: TestInfo['attachments']) => {
  for (const a of attachments)
    this._attach(a, this._parentStep()?.stepId);
  return this.attachments.length;
};

-> direct assignment creates an enumerable property on the array.

• no existing tests compare test.info().attachments directly with toEqual([]);
• tests only compare individual attachment objects or arrays from reports;
• bug was discovered when implementing the same pattern for annotations.push, which does have direct equality tests.

Expected behavior

1. wrapping arr methods should not affect arr eq checks;
2. Object.keys(testInfo.attachments) should return [] for an empty attachments arr;
3. expect(testInfo.attachments).toEqual([]) should pass for empty attachments;
4. push should be non-enumerable (like built-in arr methods).

Actual behavior

1. direct assignment makes the push enumerable;
2. Object.keys(testInfo.attachments) returns ['push'] even for empty arrs;
3. tests toEqual() sees the enumerable property and fails with: "Received: serializes to the same string";
4. tests that compare testInfo.attachments directly will fail unexpectedly.

Additional context

example of how it should be handled https://github.com/microsoft/playwright/pull/37761/files#diff-4f61694176d25f70ab6fc3d94b43ef85e9c178d8ecc5680268046e534db1515fR223

Environment

System:
  OS: Linux 6.2 Ubuntu 22.04.3 LTS 22.04.3 LTS (Jammy Jellyfish)
  CPU: (8) arm64
Binaries:
  Node: 18.19.0 - ~/.nvm/versions/node/v18.19.0/bin/node
  npm: 10.2.3 - ~/.nvm/versions/node/v18.19.0/bin/npm
npmPackages:
  @playwright/test: 1.56.0 => 1.56.0

[vladlearns]

fix is here #37814