fix(git-sync): preserve subpages.recursive and details.open on round trip

Found proactively by deepening the round-trip test from node-TYPE survival to
ATTRIBUTE fidelity (distinctive attr values per node). Two real losses (the
other 3 candidates — mathInline/mathBlock/pageEmbed — were verified to be
correct; the probe had used wrong attr names):

- subpages `recursive`: the converter emitted a bare div and the schema mirror
  didn't model the attr, so a recursive subpages reverted to non-recursive on a
  round trip. Now emits `data-recursive="true"` and the mirror parses it back
  (matching @docmost/editor-ext).
- details `open`: the `open` (collapsed/expanded) state lives on the details
  node, but the converter emitted the `<details>` wrapper from the summary case
  without it, so the state was dropped. The wrapper now carries `open`.

The round-trip test now also asserts attribute fidelity (12 cases) so these are
locked. Schema-surface snapshot updated for the new subpages attr.

git-sync vitest 671 (+1 expected-fail), §13.1 gate 27.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/git-sync/src/lib/docmost-schema.ts

@@ -928,6 +928,17 @@ const Subpages = Node.create({
   atom: true,
   defining: true,
   draggable: true,
+  addAttributes() {
+    return {
+      recursive: {
+        default: false,
+        parseHTML: (el: HTMLElement) =>
+          el.getAttribute("data-recursive") === "true",
+        renderHTML: (attrs: Record<string, any>) =>
+          attrs.recursive ? { "data-recursive": "true" } : {},
+      },
+    };
+  },
   parseHTML() {
     return [{ tag: 'div[data-type="subpages"]' }];
   },

packages/git-sync/src/lib/markdown-converter.ts

@@ -445,16 +445,20 @@ export function convertProseMirrorToMarkdown(content: any): string {
         const calloutContent = nodeContent.map(processNode).join("\n");
         return `:::${calloutType.toLowerCase()}\n${calloutContent}\n:::`;
 
-      case "details":
-        return nodeContent.map(processNode).join("\n");
+      case "details": {
+        // The `open` (collapsed/expanded) state lives on the details node, NOT on
+        // the summary, so emit the <details> wrapper HERE carrying it — otherwise
+        // the open state is dropped on a round trip. The schema's details node
+        // parses `open` back from the attribute.
+        const open = node.attrs?.open ? " open" : "";
+        return `<details${open}>\n${nodeContent.map(processNode).join("")}</details>`;
+      }
 
       case "detailsSummary":
-        const summaryText = nodeContent.map(processNode).join("");
-        return `<details>\n<summary>${summaryText}</summary>\n`;
+        return `<summary>${nodeContent.map(processNode).join("")}</summary>\n\n`;
 
       case "detailsContent":
-        const detailsText = nodeContent.map(processNode).join("\n");
-        return `${detailsText}\n</details>`;
+        return `${nodeContent.map(processNode).join("\n")}\n`;
 
       case "mathInline": {
         // The schema's `text` attribute has no parseHTML, so TipTap's default
@@ -648,13 +652,16 @@ export function convertProseMirrorToMarkdown(content: any): string {
         // (the divider silently disappeared and could not round-trip).
         return `<div data-type="pageBreak"></div>`;
 
-      case "subpages":
+      case "subpages": {
         // Emit the schema-matching div[data-type="subpages"] so marked passes it
         // through as a block and generateJSON rebuilds the subpages atom. The old
         // `{{SUBPAGES}}` literal had no parseHTML inverse, so on import it stayed
         // as plain text — the embed rendered as the literal "{{SUBPAGES}}" on the
         // page after a round-trip (red-team: subpages round-trip data loss).
-        return `<div data-type="subpages"></div>`;
+        // `data-recursive` carries the recursive toggle so it round-trips too.
+        const recursive = node.attrs?.recursive ? ` data-recursive="true"` : "";
+        return `<div data-type="subpages"${recursive}></div>`;
+      }
 
       case "status": {
         // Inline status pill. The schema reads the label from the element's

packages/git-sync/test/roundtrip-all-nodes.test.ts

@@ -107,3 +107,35 @@ describe('git-sync converter: every node/mark type survives a Markdown round tri
     });
   }
 });
+
+// A node surviving as the right TYPE is necessary but not sufficient — its
+// attributes must survive too. Each case carries a DISTINCTIVE attribute value
+// (real attr names, verified against the schema) that must reappear after a
+// round trip. This caught `subpages.recursive` and `details.open` being dropped.
+describe('git-sync converter: node ATTRIBUTES survive a Markdown round trip', () => {
+  const ATTR_CASES: Array<{ name: string; doc: any; needles: string[] }> = [
+    { name: 'callout type', doc: doc({ type: 'callout', attrs: { type: 'warning' }, content: [P(T('x'))] }), needles: ['warning'] },
+    { name: 'image dimensions/align/attachmentId', doc: doc({ type: 'image', attrs: { src: '/f/x.png', width: '777', height: '555', align: 'right', attachmentId: 'ATT777' } }), needles: ['777', '555', 'right', 'ATT777'] },
+    { name: 'subpages recursive', doc: doc({ type: 'subpages', attrs: { recursive: true } }), needles: ['"recursive":true'] },
+    { name: 'details open', doc: doc({ type: 'details', attrs: { open: true }, content: [{ type: 'detailsSummary', content: [T('S')] }, { type: 'detailsContent', content: [P(T('b'))] }] }), needles: ['"open":'] },
+    { name: 'mathInline formula', doc: doc(P({ type: 'mathInline', attrs: { text: 'E=mc^7' } })), needles: ['E=mc^7'] },
+    { name: 'mathBlock formula', doc: doc({ type: 'mathBlock', attrs: { text: '\\sum_7' } }), needles: ['sum_7'] },
+    { name: 'pageEmbed sourcePageId', doc: doc({ type: 'pageEmbed', attrs: { sourcePageId: 'PAGE777' } }), needles: ['PAGE777'] },
+    { name: 'video dimensions/attachmentId', doc: doc({ type: 'video', attrs: { src: '/f/v.mp4', width: '888', attachmentId: 'VID888' } }), needles: ['888', 'VID888'] },
+    { name: 'status text/color', doc: doc(P({ type: 'status', attrs: { text: 'InProgress777', color: 'orange' } })), needles: ['InProgress777', 'orange'] },
+    { name: 'mention entityId/label', doc: doc(P({ type: 'mention', attrs: { id: 'M1', label: 'Alice', entityType: 'user', entityId: 'ENT777' } })), needles: ['Alice', 'ENT777'] },
+    { name: 'columns widths', doc: doc({ type: 'columns', content: [{ type: 'column', attrs: { width: '37%' }, content: [P(T('L'))] }, { type: 'column', attrs: { width: '63%' }, content: [P(T('R'))] }] }), needles: ['37%', '63%'] },
+    { name: 'highlight color', doc: doc(P(T('x', [{ type: 'highlight', attrs: { color: '#abcdef' } }]))), needles: ['#abcdef'] },
+  ];
+  for (const { name, doc: original, needles } of ATTR_CASES) {
+    it(`preserves ${name}`, async () => {
+      const md = convertProseMirrorToMarkdown(original);
+      const back = JSON.stringify(await markdownToProseMirror(md));
+      for (const needle of needles) {
+        // The value must survive in the re-imported doc (or in the markdown the
+        // schema parses it back from).
+        expect(`${back} ${md}`).toContain(needle);
+      }
+    });
+  }
+});

packages/git-sync/test/schema-surface-snapshot.test.ts

@@ -99,7 +99,7 @@ const expectedSurface: SurfaceEntry[] = [
   { name: "pdf", kind: "node", attrs: ["attachmentId", "height", "name", "placeholder", "size", "src", "width"] },
   { name: "status", kind: "node", attrs: ["color", "text"] },
   { name: "strike", kind: "mark", attrs: [] },
-  { name: "subpages", kind: "node", attrs: [] },
+  { name: "subpages", kind: "node", attrs: ["recursive"] },
   { name: "subscript", kind: "mark", attrs: [] },
   { name: "superscript", kind: "mark", attrs: [] },
   { name: "table", kind: "node", attrs: [] },