Core: classify spec data blocks by Vega-Lite fidelity (spec-data) for dataset refs

src/core/rendering.test.ts

@@ -203,6 +203,26 @@ describe('prepareSpecForRender — dataset resolution (spec §04 Rendering Contr
     expect(out.data).toEqual({ name: 'local' });
   });
 
+  test('native Vega-Lite data with a name label is left untouched (not resolved, never throws)', () => {
+    // A name on inline/url data, or a generator, is native Vega-Lite — even when
+    // the name is absent from the library. Resolution must not touch or reject it.
+    const inline = { data: { name: 'pts', values: [{ a: 1 }] }, mark: 'point' };
+    expect(prepareSpecForRender(inline, { datasets }).data).toEqual({
+      name: 'pts',
+      values: [{ a: 1 }],
+    });
+    const url = { data: { name: 'remote', url: 'https://x/y.csv' } };
+    expect(prepareSpecForRender(url, { datasets }).data).toEqual({
+      name: 'remote',
+      url: 'https://x/y.csv',
+    });
+    const gen = { data: { name: 'seq', sequence: { start: 0, stop: 5 } } };
+    expect(prepareSpecForRender(gen, { datasets }).data).toEqual({
+      name: 'seq',
+      sequence: { start: 0, stop: 5 },
+    });
+  });
+
   test('resolution runs before fit-mode: a ref + fit mode produce both transforms', () => {
     const spec = { data: { name: 'JsonDs' }, mark: 'bar' };
     const out = prepareSpecForRender(spec, { datasets, fitMode: 'full' }) as unknown as {