vitest-dev/vitest · error

Task was not found

Error message

Task ${id} was not found

What it means

rerunTask looks up the task by id in state.idMap; if the id was never collected/registered it throws. This is a watcher-driven API, so the error means an id was supplied that Vitest never indexed — typically a stale, fabricated, or post-deletion id.

Solutions

1. Guard with state.idMap.has(id) (or state.getTask(id)) before calling rerunTask.
2. Re-run collection so the idMap is rebuilt before rerunning.
3. Ensure the source file still exists and was imported successfully in the last run.

Example fix

// before
await vitest.rerunTask(id)

// after
if (!vitest.state.idMap.has(id)) {
  await vitest.collect() // rebuild idMap
}
if (vitest.state.idMap.has(id)) {
  await vitest.rerunTask(id)
}

function taskExists(state, id) {
  return state.idMap.has(id)
}
// before: if (!taskExists(vitest.state, id)) await vitest.collect()

function isKnownTaskId(state, id): id is string {
  return typeof id === 'string' && state.idMap.has(id)
}

When it happens

Trigger: Calling rerunTask(id) (usually via watcher/IPC/programmatic API) with an id that is not a key in state.idMap, e.g. after the source file was removed, after state was cleared, or with a hardcoded/external id.

Common situations: Watcher rerun after file deletion; programmatic API misuse with hardcoded ids; stale id captured from a previous run; rerun triggered during teardown.

Related errors

• Test specification for task

AI-assisted analysis of vitest-dev/vitest@1fa9837ec2 (2026-08-11). Data as JSON: /api/errors/a2fcf1afa2133f04. Report an issue: GitHub.

Appendix: source

Thrown at packages/vitest/src/node/core.ts:1279

      files = files.filter(file => filteredFiles.some(f => f.moduleId === file))
    }

    const specifications = files.flatMap(file => this.getModuleSpecifications(file))
    await Promise.all([
      this.report('onWatcherRerun', files, trigger),
      ...this._onUserTestsRerun.map(fn => fn(specifications)),
    ])
    const testResult = await this.runFiles(specifications, allTestsRun)

    await this.report('onWatcherStart', this.state.getFiles(files))
    return testResult
  }

  /** @internal */
  async rerunTask(id: string): Promise<void> {
    const task = this.state.idMap.get(id)
    if (!task) {
      throw new Error(`Task ${id} was not found`)
    }

    const reportedTask = this.state.getReportedEntityById(id)
    if (!reportedTask) {
      throw new Error(`Test specification for task ${id} was not found`)
    }

    const specifications = [reportedTask.toTestSpecification()]
    await Promise.all([
      this.report(
        'onWatcherRerun',
        [task.file.filepath],
        'tasks' in task ? 'rerun suite' : 'rerun test',
      ),
      ...this._onUserTestsRerun.map(fn => fn(specifications)),
    ])
    await this.runFiles(specifications, false)
    await this.report(

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