fix(rowbinary): support compiling empty Tuple() type AST

skills/clickhouse-js-node-rowbinary/src/readers/compile.ts

@@ -162,6 +162,8 @@ function dataTypeReader(node: Node): Reader<unknown> {
       return variantReader(node);
     case "Nested":
       return nestedReader(node);
+    case "Tuple":
+      return tupleReader(node);
 
     // --- parameterized scalars ---
     case "FixedString":
@@ -211,7 +213,9 @@ function tupleReader(node: Node): Reader<unknown> {
   const readers = node.arguments.map(astToReader);
   const names = node.element_names;
   const named =
-    names.length === readers.length && names.every((n) => n.length > 0);
+    names.length > 0 &&
+    names.length === readers.length &&
+    names.every((n) => n.length > 0);
   if (named) {
     const fields: Record<string, Reader<unknown>> = {};
     for (let i = 0; i < names.length; i++) fields[names[i]!] = readers[i]!;

skills/clickhouse-js-node-rowbinary/tests/compile.test.ts

@@ -111,4 +111,25 @@ describe("astToReader (AST -> Reader fold)", () => {
       /cannot build a column reader/,
     );
   });
+
+  it("folds an empty Tuple to an empty array reader", () => {
+    const read = reader("Tuple()");
+    const s = new Cursor(Buffer.alloc(0));
+    expect(read(s)).toEqual([]);
+    expect(s.pos).toBe(0);
+  });
+
+  it("folds a nested empty Tuple", () => {
+    const read = reader("Tuple(Tuple())");
+    const s = new Cursor(Buffer.alloc(0));
+    expect(read(s)).toEqual([[]]);
+    expect(s.pos).toBe(0);
+  });
+
+  it("folds an empty Tuple alongside other columns", () => {
+    const read = reader("Tuple(Tuple(), UInt8)");
+    const s = new Cursor(Buffer.from([0x05]));
+    expect(read(s)).toEqual([[], 5]);
+    expect(s.pos).toBe(1);
+  });
 });