require-vitest-coverage-provider-when-enabled

Require explicit test.coverage.provider when coverage is enabled.

Rule catalog ID: R043

Targeted pattern scope

• vitest.config.*
• vitest.workspace.*
• vite.config.* when Vitest coverage is configured
• test.coverage.enabled: true

What this rule reports

This rule reports enabled coverage blocks that omit test.coverage.provider.

Why this rule exists

Coverage provider selection impacts instrumentation behavior and output consistency. Making it explicit in shared config avoids hidden defaults and cross-environment drift.

❌ Incorrect

import { defineConfig } from "vitest/config";

export default defineConfig({
    test: {
        coverage: {
            enabled: true,
        },
    },
});

✅ Correct

import { defineConfig } from "vitest/config";

export default defineConfig({
    test: {
        coverage: {
            enabled: true,
            provider: "v8",
        },
    },
});

Behavior and migration notes

• this rule checks static enabled/provider values only
• it reports once per coverage scope missing a provider

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 provider configuration is intentionally delegated to runtime-only flags.

Package documentation

• Vitest config reference

Further reading

• require-vitest-coverage-reporter-when-enabled