Function compileQuery

packages/db/src/query/compiler/index.ts:162–954

(
  rawQuery: QueryIR,
  inputs: Record<string, KeyedStream>,
  collections: Record<string, Collection<any, any, any, any, any>>,
  subscriptions: Record<string, CollectionSubscription>,
  callbacks: Record<string, LazyCollectionCallbacks>,
  lazySources: Set<string>,
  optimizableOrderByCollections: Record<string, OrderByOptimizationInfo>,
  setWindowFn: (windowFn: (options: WindowOptions) => void) => void,
  cache: QueryCache = new WeakMap(),
  queryMapping: QueryMapping = new WeakMap(),
  // For includes: parent key stream to inner-join with this query's FROM
  parentKeyStream?: KeyedStream,
  childCorrelationField?: PropRef,
)

 * @returns A CompilationResult with the pipeline, source WHERE clauses, and alias metadata
 */
export function compileQuery(
  rawQuery: QueryIR,
  inputs: Record<string, KeyedStream>,
  collections: Record<string, Collection<any, any, any, any, any>>,
  subscriptions: Record<string, CollectionSubscription>,
  callbacks: Record<string, LazyCollectionCallbacks>,
  lazySources: Set<string>,
  optimizableOrderByCollections: Record<string, OrderByOptimizationInfo>,
  setWindowFn: (windowFn: (options: WindowOptions) => void) => void,
  cache: QueryCache = new WeakMap(),
  queryMapping: QueryMapping = new WeakMap(),
  // For includes: parent key stream to inner-join with this query's FROM
  parentKeyStream?: KeyedStream,
  childCorrelationField?: PropRef,
): CompilationResult {
  // Check if the original raw query has already been compiled
  const cachedResult = cache.get(rawQuery)
  if (cachedResult) {
    return cachedResult
  }

  // Validate the raw query BEFORE optimization to check user's original structure.
  // This must happen before optimization because the optimizer may create internal
  // subqueries (e.g., for predicate pushdown) that reuse aliases, which is fine.
  validateQueryStructure(rawQuery)

  // Optimize the query before compilation
  const { optimizedQuery, sourceWhereClauses } = optimizeQuery(rawQuery)
  // Use a mutable binding so we can shallow-clone select before includes mutation
  let query = optimizedQuery

  // Create mapping from optimized query to original for caching
  queryMapping.set(query, rawQuery)
  mapNestedQueries(query, rawQuery, queryMapping)

  // Create a copy of the inputs map to avoid modifying the original
  const allInputs = { ...inputs }

  // Track alias to collection id relationships discovered during compilation.
  // This includes all user-declared aliases plus inner aliases from subqueries.
  const aliasToCollectionId: Record<string, string> = {}

  // Track alias remapping for subqueries (outer alias → inner alias)
  // e.g., when .join({ activeUser: subquery }) where subquery uses .from({ user: collection })
  // we store: aliasRemapping['activeUser'] = 'user'
  const aliasRemapping: Record<string, string> = {}

  // Create a map of source aliases to input streams.
  // Inputs MUST be keyed by alias (e.g., `{ employee: input1, manager: input2 }`),
  // not by collection ID. This enables per-alias subscriptions where different aliases
  // of the same collection (e.g., self-joins) maintain independent filtered streams.
  const sources: Record<string, KeyedStream> = {}

  // Process the FROM clause to get the source stream.
  const {
    alias: mainSource,
    collectionId: mainCollectionId,
    pipeline: initialPipeline,