vitest-dev/vitest · error · Error

Task instance was not found for ${runnerTask.type} "${runner

Error message

Task instance was not found for ${runnerTask.type} "${runnerTask.name}"

What it means

Thrown by `getReportedTask` (reported-tasks.ts:779) when a runner task (the low-level `RunnerTask` from the test runner) is looked up in `project.vitest.state.reportedTasksMap` / via `getReportedEntity` but no reported entity has been registered for it. This is an internal invariant: every runner task that the reporter layer processes must have been stored first via `storeTask`. Encountering it indicates a state-tracking bug or out-of-order access inside Vitest rather than a user configuration problem.

Source

Thrown at packages/vitest/src/node/reporters/reported-tasks.ts:779

   */
  readonly workerId: number
}

function storeTask(
  project: TestProject,
  runnerTask: RunnerTask,
  reportedTask: TestCase | TestSuite | TestModule,
): void {
  project.vitest.state.reportedTasksMap.set(runnerTask, reportedTask)
}

function getReportedTask(
  project: TestProject,
  runnerTask: RunnerTask,
): TestCase | TestSuite | TestModule {
  const reportedTask = project.vitest.state.getReportedEntity(runnerTask)
  if (!reportedTask) {
    throw new Error(
      `Task instance was not found for ${runnerTask.type} "${runnerTask.name}"`,
    )
  }
  return reportedTask
}

function getSuiteState(task: RunnerTestSuite | RunnerTestFile): TestSuiteState {
  const mode = task.mode
  const state = task.result?.state
  if (mode === 'skip' || mode === 'todo' || state === 'skip' || state === 'todo') {
    return 'skipped'
  }
  if (state == null || state === 'run' || state === 'only') {
    return 'pending'
  }
  if (state === 'fail') {
    return 'failed'
  }

View on GitHub (pinned to d568f8ce37)

Solutions

1. If you hit this in app code, report a Vitest bug with a minimal reproduction (it signals an internal consistency violation).
2. In custom reporters, only access reported tasks during/after the hooks that guarantee they exist (e.g. `onTestRunEnd`, `onTaskUpdate`) rather than early lifecycle hooks.
3. Upgrade to the latest patch release; this kind of invariant break is typically fixed quickly.

try {
  const entity = project.vitest.state.getReportedEntity(runnerTask)
  if (!entity) return // guard instead of letting Vitest throw
  // ... use entity
} catch (e) {
  if (e instanceof Error && /Task instance was not found/.test(e.message)) {
    // skip tasks without reported entities
  } else throw e
}

When it happens

Trigger: A custom reporter calling APIs that walk runner tasks before the reported-task map is populated; an internal ordering change where a task event arrives before its `storeTask` call; mutating or reusing runner task objects across Vitest instances.

Common situations: Building a custom reporter that touches `experimental_getRunnerTask` / internal task state at the wrong lifecycle hook; running against an in-development Vitest build with a regression in task tracking.

Related errors

• Unknown suite state: ${state}
• Task ${id} was not found
• Test specification for task ${id} was not found
• Cannot find iframe with id ${event.iframeId}
• Cannot spawn child server without a parent dev server.

AI-assisted analysis of vitest-dev/vitest@d568f8ce37 (2026-08-03). Data as JSON: /data/errors/8758b46771599e50.json. Report an issue: GitHub.