chenglou/pretext · error · Error

Unsupported browser ${browser}; expected chrome or safari

Error message

Unsupported browser ${browser}; expected chrome or safari

What it means

Thrown by `parseBrowser` when the resolved browser is neither `chrome` nor `safari`. The value comes from `--browser=`, falling back to the `CORPUS_CHECK_BROWSER` env var, then `chrome`.

Source

Thrown at scripts/corpus-sweep.ts:114

function parseOptionalNumberFlag(name: string): number | null {
  const raw = parseStringFlag(name)
  if (raw === null) return null
  const parsed = Number.parseInt(raw, 10)
  if (!Number.isFinite(parsed)) {
    throw new Error(`Invalid value for --${name}: ${raw}`)
  }
  return parsed
}

function hasFlag(name: string): boolean {
  return process.argv.includes(`--${name}`)
}

function parseBrowser(value: string | null): BrowserKind {
  const browser = (value ?? process.env['CORPUS_CHECK_BROWSER'] ?? 'chrome').toLowerCase()
  if (browser !== 'chrome' && browser !== 'safari') {
    throw new Error(`Unsupported browser ${browser}; expected chrome or safari`)
  }
  return browser
}

async function loadSources(): Promise<CorpusMeta[]> {
  return await Bun.file('corpora/sources.json').json()
}

function parseOptions(): SweepOptions {
  const start = parseNumberFlag('start', 300)
  const end = parseNumberFlag('end', 900)
  const step = parseNumberFlag('step', 10)
  if (step <= 0) throw new Error('--step must be > 0')
  if (end < start) throw new Error('--end must be >= --start')
  if (parseStringFlag('samples') !== null) {
    throw new Error('--samples is obsolete for corpus-sweep; use the default step-based sweep or sampled font-matrix/taxonomy runs instead')
  }

View on GitHub (pinned to ac49b09b7d)

Solutions

Use `--browser=chrome` or `--browser=safari`.
Unset or correct `CORPUS_CHECK_BROWSER` in your shell.
For Firefox, use the accuracy/checker paths instead; the corpus sweep/taxonomy scripts intentionally support only chrome and safari.

Example fix

// before
CORPUS_CHECK_BROWSER=firefox bun run scripts/corpus-sweep.ts --id=...
// after
CORPUS_CHECK_BROWSER=chrome bun run scripts/corpus-sweep.ts --id=...

Defensive patterns

Strategy: validation

Validate before calling

const raw = (parseStringFlag('browser') ?? process.env['CORPUS_CHECK_BROWSER'] ?? 'chrome').toLowerCase()
if (raw !== 'chrome' && raw !== 'safari') {
  console.error(`Unsupported browser ${raw}; expected chrome or safari`)
  process.exit(2)
}

Type guard

const isSupportedBrowser = (v: string): v is 'chrome' | 'safari' =>
  v === 'chrome' || v === 'safari'

Prevention

Pin --browser explicitly in CI rather than relying on an env var.
Remember these corpus scripts support only chrome and safari; use accuracy paths for Firefox.
Unset CORPUS_CHECK_BROWSER when switching tools to avoid stale values.

When it happens

Trigger: `--browser=firefox` or `CORPUS_CHECK_BROWSER=edge bun run scripts/corpus-sweep.ts ...`.

Common situations: Wanting Firefox coverage (these corpus scripts are chrome/safari only by design); an env var left set by another tool; a typo like `--browser=chrom`.

Related errors

AI-assisted analysis of chenglou/pretext@ac49b09b7d (2026-08-12). Data as JSON: /api/errors/49abfbe6421b0ea5. Report an issue: GitHub.