no-unsafe-vitest-flags

Disallow unsafe Vitest execution flags that can hide failing tests or runtime errors.

Rule catalog ID: R018

Targeted pattern scope

• vitest.config.*
• vitest.workspace.*
• vite.config.* when a Vitest test block is used
• root and inline project test option objects

What this rule reports

This rule reports:

• test.allowOnly: true
• test.dangerouslyIgnoreUnhandledErrors: true

Why this rule exists

These flags weaken core test safety guarantees:

• allowOnly: true can allow focused tests (.only) to pass while silently skipping the rest of the suite
• dangerouslyIgnoreUnhandledErrors: true can hide asynchronous failures and produce misleading green runs

This plugin is focused on robust Vite/Vitest configuration quality, so catching these config-level hazards is a repository-specific, high-signal check.

❌ Incorrect

import { defineConfig } from "vitest/config";

export default defineConfig({
    test: {
        allowOnly: true,
        dangerouslyIgnoreUnhandledErrors: true,
    },
});

✅ Correct

import { defineConfig } from "vitest/config";

export default defineConfig({
    test: {
        allowOnly: false,
        dangerouslyIgnoreUnhandledErrors: false,
    },
});

Behavior and migration notes

• this rule only reports explicit true toggles for unsafe flags
• if these options are omitted, Vitest defaults still apply
• if you need temporary local overrides, prefer ephemeral CLI/dev-only config branching rather than committed repository config

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 test strategy intentionally allows focused test execution or ignored unhandled errors in committed config and you accept that risk.

Package documentation

• Vitest config reference
• Vitest allowOnly option

Further reading

• vitest preset
• no-zero-vitest-timeout