dotansimha/apollo-very-pessimism

This repository reproduced a memory leak introduced in Apollo-Client v3.

This leak occurs when you use watchQuery along with context passes. Due to the fact the AC3 keeps an internal pointer to that context object, and something internally with Apollo cleanup mechanism isn't functioning, it causes this object to retain in memory, even after cleaning

Actual issue: apollographql/apollo-client#7149

Related Issues:

• apollographql/apollo-client#7086
• apollographql/apollo-client#6985
• apollographql/apollo-client#7013

How to run this test:

1. Run yarn to install deps.
2. Run yarn test to run Jest and the test - if you are getting a timeout after 20s, it means that Apollo-Client still holds a reference to our object.
3. You can run yarn test:debug and and then attach Chrome DevTools - you should be able to use that to take Heap snapshots (no need for breakpoints, I added debugger statements on the important places, and it tells you when to take the snapshot).
4. If you'll comment out the L51 (context: myContext,) - test will pass.

Heap Snapshot

You can find a heap snapshot the describes the issue in this repo (Heap-20201012T074835.heapsnapshot.zip). You can open it with Chrome DevTools and inspect. This heap snapshot was saved after unsubscribe has been called, and after GC has been triggered.