OOM crashes

[ceedubs]

Describe and demonstrate the bug

I don't know a simple way to reproduce this. But for the last couple of hours I have doing a lot of the following commands on the nimbus codebase while searching for unused code and code that has been upstreamed to libraries:

• ls
• dependents
• delete.term
• delete.namespace
• view

Often I'm calling these with numbered args from ls and dependents output.

2 or 3 times my computer has frozen and my fans have gone full throttle (presumably from CPU usage). One time I gave up and did a hard power reset of my computer and the other time my OS had killed my tmux process when I returned to my computer ~10 min later.

I'm guessing that there is a memory leak and that I could get this to fail more gracefully by setting a max memory limit on the Haskell runtime. But ideally this wouldn't be necessary.

Environment (please complete the following information):

• ucm --version 335512e331339cd496db97b6d3bead1efc090f42 (via nix run)
• OS/Architecture: x86 NixOS

[aryairani]

Let's reevaluate this after #5041, though it shouldn't be leaking per se.

In Haskell can we detect memory pressure and reduce our cache sizes?