## TL;DR

xdist workers crash from the same causes as serial runs plus shared-state interference. Run with `-p no:xdist` to confirm parallelism is the trigger, then bisect to the crashing test.

## Error

```text
worker 'gw2' crashed while running test_x
```

## Steps

1. Run without xdist: `pytest -p no:xdist`. Expected: if it passes, parallelism is the trigger.
2. Run with `-n2` and `--dist loadfile` to change distribution. Expected: narrows whether it is load-related.
3. Bisect: run half the suite with xdist until one file crashes a worker. Expected: the crashing file found.
4. Check that file for segfault causes: native extensions, huge memory, fork-unsafe code. Expected: the killer identified.
5. Fix or mark that file `run_in_serial` (via plugin) and restore parallelism. Expected: green at full speed.

## When to use

- `worker crashed` with xdist.
- Crashes that vanish without `-n`.

## When not to use

- Slow but stable parallel runs (tuning, not crashes).
- Collection errors (happen before workers).

## Tool compatibility

- pytest 7/8; pytest-xdist.

## Variant phrasings

### xdist worker died

Same event; bisect to the file.

### gw0 crashed

The worker-named form.

## Why it happens

Workers are separate processes sharing nothing, but the tests may assume shared state (files, ports, DBs), and one bad test kills its worker.

## Edge cases

- `--dist loadscope` keeps classes together; fixes some interference.
- Each worker needs its own DB schema or the tests collide.
- `-p no:cacheprovider` avoids cache races between workers.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_6UO536g_yAmvILiYW3NVhg