chenglou/pretext · error · Error

Corpus font matrix report was missing rows for ${meta.id} ($

Error message

Corpus font matrix report was missing rows for ${meta.id} (${variant.id})

What it means

Thrown by the font-matrix sweep after a browser corpus page posts a 'ready' report that omits the `rows` array for the current font variant. It guards against silently treating an empty/partial measurement as zero mismatches. The page either measured no width or the POST side channel delivered an incomplete payload.

Source

Thrown at scripts/corpus-font-matrix.ts:487

    const report = await (async () => {
      try {
        return await loadPostedReport(
          session,
          url,
          () => reportServer.waitForReport(null),
          requestId,
          options.browser,
          options.timeoutMs,
        )
      } finally {
        reportServer.close()
      }
    })()
    if (report.status === 'error') {
      throw new Error(`Corpus page returned error for ${meta.id} (${variant.id}): ${report.message ?? 'unknown error'}`)
    }
    if (report.rows === undefined) {
      throw new Error(`Corpus font matrix report was missing rows for ${meta.id} (${variant.id})`)
    }

    const mismatches: VariantResult['mismatches'] = report.rows
      .filter(row => Math.round(row.diffPx) !== 0)
      .map(row => ({
        width: row.width,
        diffPx: Math.round(row.diffPx),
        predictedHeight: Math.round(row.predictedHeight),
        actualHeight: Math.round(row.actualHeight),
      }))
    const exactCount = report.exactCount ?? (report.rows.length - mismatches.length)

    variantResults.push({
      id: variant.id,
      label: variant.label,
      font: variant.font,
      lineHeight: variant.lineHeight,
      widthCount: report.rows.length,

View on GitHub (pinned to ac49b09b7d)

Solutions

1. Re-run the matrix; if it persists, open the same `/corpus?id=...&widths=...&font=...&lineHeight=...&report=1` URL in a headed browser and read the console for in-page errors.
2. Check that the corpus's `min_width`/`max_width` in `corpora/sources.json` overlaps your `--start`/`--end` range; a clamped-empty width list yields no rows.
3. Raise `--timeout` (or `CORPUS_CHECK_TIMEOUT_MS`); a measurement exceeding the timeout can post a 'ready' report before rows attach.
4. Confirm the POST side channel (reportEndpoint) is reachable from the page; a blocked endpoint can drop the rows field.

Example fix

// before: corpus min_width clamps the sweep range empty
// corpora/sources.json: { "id": "x", "min_width": 950 }
// invocation:  --start=300 --end=900  -> no widths in range -> no rows

// after: widen the sweep to overlap the corpus bounds
bun run scripts/corpus-font-matrix.ts --id=x --start=900 --end=1200

const widths = getSweepWidths(meta, options)
if (widths.length === 0) {
  console.error(`No widths in range for ${meta.id}; adjust --start/--end or corpus min_width/max_width`)
  process.exit(0)
}

When it happens

Trigger: Run `bun run scripts/corpus-font-matrix.ts --id=...` and the in-page harness posts `{status:'ready'}` with no `rows`. Typical causes: the `&widths=` list resolved to nothing because the corpus `min_width`/`max_width` clamped the range empty, the page threw before building rows, or the POST side channel truncated the payload.

Common situations: A corpus's `min_width`/`max_width` in `corpora/sources.json` excludes every width in the `--start`/`--end` sweep range; a stale `/corpus` page build that doesn't emit rows for the requested font variant; a reportEndpoint POST that drops the rows field under a firewall or timeout.

Related errors

• Corpus sweep report was missing rows for ${corpusId}
• Corpus taxonomy report was missing rows for ${meta.id}
• corpus-check exited with status ${result.status ?? 'unknown'
• Corpus page returned error for ${meta.id}: ${report.message
• Corpus page returned error for ${meta.id}: ${report.message

AI-assisted analysis of chenglou/pretext@ac49b09b7d (2026-08-12). Data as JSON: /api/errors/5d4cb54e0004886b. Report an issue: GitHub.