fix(document-api): avoid empty node IDs in markdownToFragment structural fragments

Author: harbournick

packages/super-editor/src/document-api-adapters/helpers/sd-projection.ts

@@ -981,8 +981,9 @@ function projectInlineFallback(pmNode: ProseMirrorNode): SDRun {
 // Helpers: node ID
 // ---------------------------------------------------------------------------
 
-function resolveNodeId(pmNode: ProseMirrorNode): string {
-  return pmNode.attrs?.sdBlockId ?? '';
+function resolveNodeId(pmNode: ProseMirrorNode): string | undefined {
+  const id = pmNode.attrs?.sdBlockId;
+  return typeof id === 'string' && id.length > 0 ? id : undefined;
 }
 
 // ---------------------------------------------------------------------------

packages/super-editor/src/document-api-adapters/plan-engine/insert-structured-wrapper.test.ts

@@ -7,6 +7,7 @@ import { insertStructuredWrapper } from './plan-wrappers.js';
 import { registerBuiltInExecutors } from './register-executors.js';
 import { clearExecutorRegistry } from './executor-registry.js';
 import { resolveTextTarget } from '../helpers/adapter-utils.js';
+import { nodeAllowsSdBlockIdAttr } from '../../extensions/block-node/block-node.js';
 
 let docData: Awaited<ReturnType<typeof loadTestDataForEditorTests>>;
 
@@ -273,6 +274,26 @@ describe('insertStructuredWrapper — table separators', () => {
       }
     }
   });
+
+  it('assigns sdBlockId to all block nodes that support it after markdown table insert', () => {
+    const result = insertStructuredWrapper(editor, {
+      value: '| A | B |\n| --- | --- |\n| foo | bar |',
+      type: 'markdown',
+    });
+    expect(result.success).toBe(true);
+
+    const missing: Array<{ type: string; pos: number; id: unknown }> = [];
+    editor.state.doc.descendants((node, pos) => {
+      if (!nodeAllowsSdBlockIdAttr(node)) return true;
+      const id = node.attrs?.sdBlockId;
+      if (typeof id !== 'string' || id.length === 0) {
+        missing.push({ type: node.type.name, pos, id });
+      }
+      return true;
+    });
+
+    expect(missing).toEqual([]);
+  });
 });
 
 describe('insertStructuredWrapper — list numbering rollback', () => {

packages/super-editor/src/document-api-adapters/structural-write-engine/structural-write-engine.test.ts

@@ -5,6 +5,7 @@ import { registerBuiltInExecutors } from '../plan-engine/register-executors.js';
 import { clearExecutorRegistry } from '../plan-engine/executor-registry.js';
 import { insertStructuredWrapper, replaceStructuredWrapper } from '../plan-engine/plan-wrappers.js';
 import { executePlan } from '../plan-engine/executor.js';
+import { markdownToFragmentAdapter } from '../markdown-to-fragment-adapter.js';
 import { executeStructuralInsert, executeStructuralReplace, materializeFragment } from './index.js';
 import { enforceNestingPolicy } from './nesting-guard.js';
 import { validateDocumentFragment } from '@superdoc/document-api';
@@ -250,6 +251,38 @@ describe('replaceStructuredWrapper', () => {
     expect(editor.state.doc.textContent).not.toContain('cell data');
   });
 
+  it('replaces a table block with markdownToFragment output', () => {
+    const seed = executeStructuralInsert(editor, {
+      content: {
+        type: 'table',
+        rows: [
+          {
+            type: 'tableRow',
+            cells: [{ type: 'tableCell', content: [{ type: 'paragraph', content: [{ type: 'text', text: 'old' }] }] }],
+          },
+        ],
+      },
+    });
+    const tableBlockId = seed.insertedBlockIds[0]!;
+
+    const parsed = markdownToFragmentAdapter(editor, {
+      markdown: '| Col A | Col B |\n| --- | --- |\n| foo | bar |',
+    });
+
+    // Regression guard: markdown projection must not emit duplicate empty IDs.
+    expect(() => validateDocumentFragment(parsed.fragment)).not.toThrow();
+
+    const result = replaceStructuredWrapper(editor, {
+      target: { kind: 'text', blockId: tableBlockId, range: { start: 0, end: 0 } },
+      content: parsed.fragment,
+    });
+
+    expect(result.success).toBe(true);
+    expect(editor.state.doc.textContent).toContain('foo');
+    expect(editor.state.doc.textContent).toContain('bar');
+    expect(editor.state.doc.textContent).not.toContain('old');
+  });
+
   it('supports dry-run mode without mutating the document', () => {
     const seed = executeStructuralInsert(editor, {
       content: { type: 'paragraph', content: [{ type: 'text', text: 'keep me' }] },