Function processJoinSource

packages/db/src/query/compiler/joins.ts:455–571

* Processes the join source (collection or sub-query)

(
  from: CollectionRef | QueryRef,
  allInputs: Record<string, KeyedStream>,
  collections: Record<string, Collection>,
  subscriptions: Record<string, CollectionSubscription>,
  callbacks: Record<string, LazyCollectionCallbacks>,
  lazySources: Set<string>,
  optimizableOrderByCollections: Record<string, OrderByOptimizationInfo>,
  setWindowFn: (windowFn: (options: WindowOptions) => void) => void,
  cache: QueryCache,
  queryMapping: QueryMapping,
  onCompileSubquery: CompileQueryFn,
  aliasToCollectionId: Record<string, string>,
  aliasRemapping: Record<string, string>,
  sourceWhereClauses: Map<string, BasicExpression<boolean>>,
)

 * Processes the join source (collection or sub-query)
 */
function processJoinSource(
  from: CollectionRef | QueryRef,
  allInputs: Record<string, KeyedStream>,
  collections: Record<string, Collection>,
  subscriptions: Record<string, CollectionSubscription>,
  callbacks: Record<string, LazyCollectionCallbacks>,
  lazySources: Set<string>,
  optimizableOrderByCollections: Record<string, OrderByOptimizationInfo>,
  setWindowFn: (windowFn: (options: WindowOptions) => void) => void,
  cache: QueryCache,
  queryMapping: QueryMapping,
  onCompileSubquery: CompileQueryFn,
  aliasToCollectionId: Record<string, string>,
  aliasRemapping: Record<string, string>,
  sourceWhereClauses: Map<string, BasicExpression<boolean>>,
): { alias: string; input: KeyedStream; collectionId: string } {
  switch (from.type) {
    case `collectionRef`: {
      const input = allInputs[from.alias]
      if (!input) {
        throw new CollectionInputNotFoundError(
          from.alias,
          from.collection.id,
          Object.keys(allInputs),
        )
      }
      aliasToCollectionId[from.alias] = from.collection.id
      return { alias: from.alias, input, collectionId: from.collection.id }
    }
    case `queryRef`: {
      // Find the original query for caching purposes
      const originalQuery = queryMapping.get(from.query) || from.query

      // Recursively compile the sub-query with cache
      const subQueryResult = onCompileSubquery(
        originalQuery,
        allInputs,
        collections,
        subscriptions,
        callbacks,
        lazySources,
        optimizableOrderByCollections,
        setWindowFn,
        cache,
        queryMapping,
      )

      // Pull up alias mappings from subquery to parent scope.
      // This includes both the innermost alias-to-collection mappings AND
      // any existing remappings from nested subquery levels.
      Object.assign(aliasToCollectionId, subQueryResult.aliasToCollectionId)
      Object.assign(aliasRemapping, subQueryResult.aliasRemapping)

      // Pull up source WHERE clauses from subquery to parent scope.
      // This enables loadSubset to receive the correct where clauses for subquery collections.
      //
      // IMPORTANT: Skip pull-up for optimizer-created subqueries. These are detected when:
      // 1. The outer alias (from.alias) matches the inner alias (from.query.from.alias)