oven-sh/bun · error

class mismatch at U+${cp.toString(16)}

Error message

class mismatch at U+${cp.toString(16)}

What it means

Error "class mismatch at U+${cp.toString(16)}" thrown in oven-sh/bun.

Source

Thrown at scripts/generate-stringwidth-tables.mjs:236

  }
  const key = block.join(",");
  let offset = blockKeyToOffset.get(key);
  if (offset === undefined) {
    offset = newStage2.length;
    blockKeyToOffset.set(key, offset);
    newStage2.push(...block);
  }
  newStage1[high] = offset;
}

if (newStage2.length - 256 > 0xffff) throw new Error("stage1 offsets no longer fit in uint16_t");

// Verify the rebuilt table roundtrips for every codepoint and preserves the
// original grapheme classes exactly.
for (let cp = 0; cp <= 0x10ffff; cp++) {
  const got = newStage3[newStage2[newStage1[cp >> 8] + (cp & 0xff)]];
  if (got !== packed(cp)) throw new Error(`roundtrip mismatch at U+${cp.toString(16)}`);
  if ((got & 0x1f) !== classOf(cp)) throw new Error(`class mismatch at U+${cp.toString(16)}`);
}

// ---------------------------------------------------------------------------
// Emit
// ---------------------------------------------------------------------------

function formatArray(values, perLine) {
  const lines = [];
  for (let i = 0; i < values.length; i += perLine) {
    lines.push("    " + values.slice(i, i + perLine).join(", ") + ",");
  }
  return lines.join("\n");
}

const output = `// clang-format off
// Generated by scripts/generate-stringwidth-tables.mjs from the Unicode
// ${UNICODE_VERSION} Character Database. Do not edit manually; regenerate with
//   bun scripts/generate-stringwidth-tables.mjs

View on GitHub (pinned to 8c5296ac45)

When it happens

Trigger: Thrown at scripts/generate-stringwidth-tables.mjs:236 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of oven-sh/bun@8c5296ac45 (2026-08-16). Data as JSON: /api/errors/37f1ab7e5648680d. Report an issue: GitHub.