fix(node): select auto search from table metadata

nodejs/__test__/fixtures/auto_fts_search.cjs

@@ -9,6 +9,8 @@ const { getRegistry } = require("../../dist/embedding/registry");
 async function main() {
   assert.equal(typeof embedding.getRegistry, "function");
   assert.equal(getRegistry().length(), 0);
+  assert.equal(embedding.getRegistry(), getRegistry());
+  assert.equal(getRegistry().length(), 2);
 
   const dir = tmp.dirSync({ unsafeCleanup: true });
   let db;

nodejs/lancedb/connection.ts

@@ -535,7 +535,7 @@ export class LocalConnection extends Connection {
       options?.indexCacheSize,
     );
 
-    let table: Table = new LocalTable(innerTable);
+    let table: Table = await LocalTable.create(innerTable);
     // "main" is the default branch, so treat it as no branch. On a real branch,
     // scope and pin in one step (yielding "version V of branch B"); otherwise
     // pin the version, if any, against main.
@@ -570,7 +570,7 @@ export class LocalConnection extends Connection {
       options?.isShallow ?? true,
     );
 
-    return new LocalTable(innerTable);
+    return LocalTable.create(innerTable);
   }
 
   private getStorageOptions(
@@ -652,7 +652,7 @@ export class LocalConnection extends Connection {
       storageOptions,
     );
 
-    return new LocalTable(innerTable);
+    return LocalTable.create(innerTable);
   }
 
   async createEmptyTable(
@@ -698,7 +698,7 @@ export class LocalConnection extends Connection {
       namespacePath ?? [],
       storageOptions,
     );
-    return new LocalTable(innerTable);
+    return LocalTable.create(innerTable);
   }
 
   async dropTable(name: string, namespacePath?: string[]): Promise<void> {

nodejs/lancedb/permutation.ts

@@ -172,7 +172,7 @@ export class PermutationBuilder {
    */
   async execute(): Promise<Table> {
     const nativeTable: NativeTable = await this.inner.execute();
-    return new LocalTable(nativeTable);
+    return LocalTable.create(nativeTable);
   }
 }
 

nodejs/lancedb/table.ts

@@ -814,10 +814,31 @@ export abstract class Table {
 
 export class LocalTable extends Table {
   private readonly inner: _NativeTable;
+  private readonly hasEmbeddingFunctions: boolean;
 
-  constructor(inner: _NativeTable) {
+  private constructor(inner: _NativeTable, hasEmbeddingFunctions: boolean) {
     super();
     this.inner = inner;
+    this.hasEmbeddingFunctions = hasEmbeddingFunctions;
+  }
+
+  /** @hidden */
+  static async create(inner: _NativeTable): Promise<LocalTable> {
+    const schemaBuf = await inner.schema();
+    const schema = tableFromIPC(schemaBuf).schema;
+    const serializedFunctions = schema.metadata.get("embedding_functions");
+    if (serializedFunctions === undefined) {
+      return new LocalTable(inner, false);
+    }
+
+    let hasEmbeddingFunctions = true;
+    try {
+      const functions = JSON.parse(serializedFunctions);
+      hasEmbeddingFunctions = !Array.isArray(functions) || functions.length > 0;
+    } catch {
+      // Preserve the existing parse error when the search is executed.
+    }
+    return new LocalTable(inner, hasEmbeddingFunctions);
   }
   get name(): string {
     return this.inner.name;
@@ -1038,7 +1059,7 @@ export class LocalTable extends Table {
     // fall back to full text search if no embedding functions are defined and the query is a string
     if (
       queryType === "auto" &&
-      (getRegistry().length() === 0 || instanceOfFullTextQuery(query))
+      (!this.hasEmbeddingFunctions || instanceOfFullTextQuery(query))
     ) {
       return this.query().fullTextSearch(query, {
         columns: ftsColumns,
@@ -1461,7 +1482,9 @@ export class Branches {
     fromRef?: string,
     fromVersion?: number,
   ): Promise<Table> {
-    return new LocalTable(await this.#inner.create(name, fromRef, fromVersion));
+    return LocalTable.create(
+      await this.#inner.create(name, fromRef, fromVersion),
+    );
   }
 
   /**
@@ -1472,7 +1495,7 @@ export class Branches {
    * latest and stays writable.
    */
   async checkout(name: string, version?: number): Promise<Table> {
-    return new LocalTable(await this.#inner.checkout(name, version));
+    return LocalTable.create(await this.#inner.checkout(name, version));
   }
 
   /** Delete a branch. */