Support passing reporter options via CLI

[hi-ogawa]

Clear and concise description of the problem

Reporter options can only be set in the config file via the tuple form reporters: [['json', { outputFile: '...' }]]. There's no CLI equivalent, except the special-cased top-level --outputFile.

So options like junit includeConsoleOutput or default summary can't be overridden from the CLI, which is awkward for CI/matrix jobs. We even ship bespoke env vars per option to work around this (e.g. VITEST_BLOB_LABEL for the blob reporter's label), which doesn't scale.

Suggested solution

Support --reporterOption.<name>.<option>, merged into the reporter's options (CLI over config):

vitest --reporter=json --reporterOption.json.outputFile=./out.json
vitest --reporter=junit --reporterOption.junit.includeConsoleOutput=false
vitest --reporter=default --reporterOption.default.summary=false
vitest --reporter=blob --reporterOption.blob.label=linux

Alternative

• Dedicated per-option flags or env vars (e.g. --junitIncludeConsoleOutput, VITEST_BLOB_LABEL) — doesn't scale, one-off per option.
• Env-var/config branching — the current workaround.

Additional context

• #9812 — CLI support for junit includeConsoleOutput (proposes --reporterOption.junit.includeConsoleOutput)
• #8070 — disable default reporter summary via CLI (proposes --reporter.default.summary)
• #5042 — config-side reporter options (shipped)
• #10031 — added blob label / VITEST_BLOB_LABEL (example of per-option env-var plumbing)
• Came up in #10621: feat(reporters)!: write json and junit reporter output files to .vitest by default #10621 (comment)

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that requests the same feature to avoid creating a duplicate.

[AriPerkkio]

For custom reporters, I'd say we should introduce a new name: string field in interface Reporter, that can be used to resolve where CLI options need to be passed.

vitest/packages/vitest/src/node/types/reporter.ts

Line 11 in d8b040c

export interface Reporter {

As string defined reporters are not yet constructed during resolveConfig, we'll probably want to pass these reporter CLI options in onInit?

vitest/packages/vitest/src/node/types/reporter.ts

Line 12 in d8b040c

onInit?: (vitest: Vitest) => void