no-vitest-max-workers-zero

Disallow invalid test.maxWorkers values (0 or empty strings).

Rule catalog ID: R041

Targeted pattern scope

vitest.config.*
vitest.workspace.*
vite.config.* when Vitest options are configured
test.maxWorkers

What this rule reports

This rule reports test.maxWorkers values that are:

0
empty strings ("", whitespace-only template/literal strings)

Why this rule exists

Invalid worker values can break parallel scheduling and create ambiguous runtime behavior. This is a high-signal static config mistake that is cheap to catch early.

❌ Incorrect

import { defineConfig } from "vitest/config";

export default defineConfig({
    test: {
        maxWorkers: 0,
    },
});

✅ Correct

import { defineConfig } from "vitest/config";

export default defineConfig({
    test: {
        maxWorkers: 2,
    },
});

Behavior and migration notes

this rule checks static literal/template values only
valid percentage-style strings (for example "50%") are not reported

ESLint flat config example

import vite from "@typpi/eslint-plugin-vite";

export default [vite.configs.strict, vite.configs.vitest];

When not to use it

Disable this rule only if your tooling intentionally injects maxWorkers dynamically and committed placeholders use empty or zero values.

Package documentation

Vitest config reference

Targeted pattern scope​

What this rule reports​

Why this rule exists​

❌ Incorrect​

✅ Correct​

Behavior and migration notes​

ESLint flat config example​

When not to use it​

Package documentation​

Further reading​