SIGBUS error with @swc/jest: Intermittent CI failures

[rheaditi]

Hello 👋🏼

We're experiencing an intermittent issue with @swc/jest that's causing our CI builds to fail. We switched from babel-jest to @swc/jest for transpiling our TypeScript project in unit tests, and since then, we've been seeing errors of this format:

  ● Test suite failed to run
    A jest worker process (pid=X) was terminated by another process: signal=SIGBUS, exitCode=null. Operating system logs may contain more information on why this occurred.

A few notable points:-

1. This issue started occurring immediately after switching to @swc/jest, the very first occurrence was on a feature branch introducing this change.
2. It happens in about 1-2.5% of our CI builds (we run upto 3000 builds per day) on our main branch.
3. The error is thrown always on the very first test that is executed, amongst 8 workers (jest is run with maxWorkers=50% on a 16 core machine). The remaining workers seem to be able to run normally, ie is run the remaining tests.
4. Re-running the build usually resolves the issue, making it difficult to reproduce.

I'm primarily looking for help reproducing this issue as without it, it's going to be impossible to debug 😓

We've tried increasing the old space memory for the Node process from 4GB to 8GB and this problem still occurs. We've measured the memory usage of all our tests with jest's --logHeapUsage and --expose-gc but the tests do not exceed usage of 1500MB.

Has anyone else encountered similar issues or have any suggestions for further investigation or potential fixes?
Thank you for your help!

---

Setup / Env details

Dependency Versions

• Node.js – v20.15.1
• @swc/jest – 0.2.37
  • @swc/core – 1.7.35
• jest – 29.7.0

CPU / Memory details of the container running the build

Linux with 64GB, 16 cores

Architecture:                       x86_64
CPU op-mode(s):                     32-bit, 64-bit
Byte Order:                         Little Endian
Address sizes:                      46 bits physical, 57 bits virtual
CPU(s):                             16
On-line CPU(s) list:                0-15
Thread(s) per core:                 1
Core(s) per socket:                 1
Socket(s):                          16
NUMA node(s):                       1
Vendor ID:                          GenuineIntel
CPU family:                         6
Model:                              106
Model name:                         Intel(R) Xeon(R) Platinum 8375C CPU @ 2.90GHz
Stepping:                           6
CPU MHz:                            2899.920
BogoMIPS:                           5799.84
Virtualization:                     VT-x
Hypervisor vendor:                  KVM
Virtualization type:                full
L1d cache:                          512 KiB
L1i cache:                          512 KiB
L2 cache:                           64 MiB
L3 cache:                           256 MiB

swc config

{
  "$schema": "https://swc.rs/schema.json",
  "jsc": {
    "parser": {
      "syntax": "typescript",
      "tsx": true,
      "decorators": true,
      "dynamicImport": true
    },
    "transform": {
      "react": {
        "runtime": "automatic",
        "pragma": "React.createElement",
        "pragmaFrag": "React.Fragment",
        "throwIfNamespace": true,
        "development": false,
        "useBuiltins": false
      }
    },
    "loose": false,
    "externalHelpers": true,
    "experimental": {
      "plugins": [
        [
          "swc_mut_cjs_exports",
          {
            "mutable": true
          }
        ]
      ]
    }
  }
}