chroma-core/chroma · error · Error

Max requires at least one rank expression

Error message

Max requires at least one rank expression

What it means

Thrown by the Max rank factory (rank.ts:546) when called with zero arguments. Max builds {$max: [...]} and requires at least one rank expression. The method form expr.max() with no arguments returns expr; only the bare factory Max() with no operands throws.

Source

Thrown at clients/new-js/packages/chromadb/src/execution/expression/rank.ts:546

export const Div = (left: RankInput, right: RankInput): RankExpression =>
  new DivRankExpression(
    requireRank(left, "Div left"),
    requireRank(right, "Div right"),
  );

export const Abs = (input: RankInput): RankExpression =>
  requireRank(input, "Abs").abs();

export const Exp = (input: RankInput): RankExpression =>
  requireRank(input, "Exp").exp();

export const Log = (input: RankInput): RankExpression =>
  requireRank(input, "Log").log();

export const Max = (...inputs: RankInput[]): RankExpression => {
  if (inputs.length === 0) {
    throw new Error("Max requires at least one rank expression");
  }
  const expressions = inputs.map((rank, index) =>
    requireRank(rank, `Max operand ${index}`),
  );
  return MaxRankExpression.create(expressions);
};

export const Min = (...inputs: RankInput[]): RankExpression => {
  if (inputs.length === 0) {
    throw new Error("Min requires at least one rank expression");
  }
  const expressions = inputs.map((rank, index) =>
    requireRank(rank, `Min operand ${index}`),
  );
  return MinRankExpression.create(expressions);
};

View on GitHub (pinned to aecdd12c8a)

Solutions

1. Pass at least one operand: Max(a, b)
2. Include a baseline for the empty case: Max(...(signals.length ? signals : [0]))
3. Skip building the expression when the list is empty

Example fix

// before
const rank = Max(...signals); // throws when signals is []

// after
const rank = signals.length ? Max(...signals) : Val(0);

const rank = signals.length
  ? Max(...signals)
  : Val(0);

try {
  const rank = Max(...signals);
} catch (e) {
  if (e instanceof Error && e.message.includes('Max requires')) {
    return Val(0);
  }
  throw e;
}

When it happens

Trigger: Calling Max(); spreading a dynamic list Max(...candidates) where candidates is empty — e.g. a 'best of selected signals' expression where no signal was selected.

Common situations: Max-over-optional-scorers UIs (pick best of enabled signals); empty candidate sets from upstream filters; conditional assembly that forgot a guaranteed baseline operand.

Related errors

• Sum requires at least one rank expression
• Mul requires at least one rank expression
• Min requires at least one rank expression
• Knn limit must be a positive integer
• ${context} must be a rank expression

AI-assisted analysis of chroma-core/chroma@aecdd12c8a (2026-08-16). Data as JSON: /api/errors/7ef6bdb0d33a8981. Report an issue: GitHub.