vercel/next.js · error

${formatIssue(issue)}

Error message

${formatIssue(issue)}

What it means

Generic passthrough logger in printNonFatalIssue: after isRelevantWarning/shouldEmitOnceWarning filtering, a Turbopack build issue (config or compile stage) that should not block the build is formatted via formatIssue and emitted with Log.warn. The message text is entirely the formatted issue payload — severity, title, and location come from Turbopack, not from this call site.

Source

Thrown at packages/next/src/server/dev/turbopack-utils.ts:74

  if (
    severity === 'warning' &&
    stage === 'config' &&
    renderStyledStringToErrorAnsi(issue.title).includes("can't be external")
  ) {
    if (onceErrorSet.has(issue)) {
      return false
    }
    onceErrorSet.add(issue)
  }

  return true
}

/// Print out an issue to the console which should not block
/// the build by throwing out or blocking error overlay.
export function printNonFatalIssue(issue: Issue) {
  if (isRelevantWarning(issue) && shouldEmitOnceWarning(issue)) {
    Log.warn(formatIssue(issue))
  }
}

export function processTopLevelIssues(
  currentTopLevelIssues: TopLevelIssuesMap,
  result: TurbopackResult
) {
  currentTopLevelIssues.clear()

  for (const issue of result.issues) {
    const issueKey = getIssueKey(issue)
    currentTopLevelIssues.set(issueKey, issue)
  }
}

export { msToNs } from '../../shared/lib/turbopack/compilation-events'

export type ChangeSubscriptions = Map<

View on GitHub (pinned to 258b1c1bc0)

Solutions

1. Address the reported Turbopack issue in the indicated file; details are in the formatted message.

When it happens

Trigger: Thrown at packages/next/src/server/dev/turbopack-utils.ts:74 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of vercel/next.js@258b1c1bc0 (2026-08-19). Data as JSON: /api/errors/a5f82e814d010e10. Report an issue: GitHub.