db.index.vector.queryNodes leaks an internal ArithmeticException when numberOfNearestNeighbours exceeds Integer.MAX_VALUE

Neo4j Version: neo4j:2026.07.1 (Docker)

Installation Method: Docker

API: Cypher (Bolt / cypher-shell) - built-in procedure

Steps to reproduce

1. Create a vector index and one node:

CREATE VECTOR INDEX vecIdx FOR (n:Doc) ON (n.emb)
  OPTIONS {indexConfig: {`vector.dimensions`: 2, `vector.similarity_function`: 'cosine'}};
CREATE (:Doc {emb: [1.0, 2.0]});

1. Query with a neighbor count above Integer.MAX_VALUE:

CALL db.index.vector.queryNodes('vecIdx', 2147483648, [1.0, 2.0]) YIELD node, score
RETURN node, score

Control: the same call with k = 2 returns the node with score 1.0.

Expected behavior

A clean client-side argument validation error.

Actual behavior

52U00: procedure exception - custom procedure execution error cause. Execution of the procedure db.index.vector.queryNodes() failed due to java.lang.ArithmeticException: integer overflow.

The procedure parameter is declared Long and only validated as > 0; Math.toIntExact(numberOfNearestNeighbours) in VectorIndexProcedures.queryNodeVectorIndex* (lines 161/184/206/229) throws an uncaught ArithmeticException that surfaces as an internal procedure error. A user-typed integer is enough - no data or index state is required beyond any existing vector index.