Function whereReferencesComputedSelectFields

packages/db/src/query/optimizer.ts:1120–1145

* Determines whether the provided WHERE clause references fields that are * computed by a subquery SELECT rather than pass-through properties. * * If true, pushing the WHERE clause into the subquery could change semantics * (since computed fields do not necessarily exist at the subquery input le

(
  select: Select,
  whereClause: BasicExpression<boolean>,
  outerAlias: string,
)

 * @returns True if WHERE references computed fields, otherwise false
 */
function whereReferencesComputedSelectFields(
  select: Select,
  whereClause: BasicExpression<boolean>,
  outerAlias: string,
): boolean {
  // Build a set of computed field names at the top-level of the subquery output
  const computed = new Set<string>()
  for (const [key, value] of Object.entries(select)) {
    if (key.startsWith(`__SPREAD_SENTINEL__`)) continue
    if (value instanceof PropRef) continue
    // Nested object or non-PropRef expression counts as computed
    computed.add(key)
  }

  const refs = collectRefs(whereClause)

  for (const ref of refs) {
    const path = (ref as any).path as Array<string>
    if (!Array.isArray(path) || path.length < 2) continue
    const alias = path[0]
    const field = path[1] as string
    if (alias !== outerAlias) continue
    if (computed.has(field)) return true
  }
  return false
}

/**
 * Detects whether a WHERE clause references the subquery alias through fields that