fix(#345): normalize CRLF before front-matter strip (review round 3)

F9 [WARNING] The line-anchored front-matter regex from round 2 requires a bare
LF after the opening `---`, so a Windows/CRLF foreign file (`---\r\n...`) slips
past the strip and leaks its front-matter into the body (where `title: Foo`
renders as a setext heading that title extraction hijacks). The canonical parser
whose regex shape this copied (page-file.ts) normalizes CRLF -> LF BEFORE its
FRONTMATTER_RE; the import path copied the regex but missed the normalization.
normalizeForeignMarkdown now replaces CRLF with LF first (which also makes
convertReferenceFootnotes' split('\n') consistent). Adds a CRLF fixture.

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

AGENTS.md

@@ -201,7 +201,7 @@ pnpm workspace (`pnpm@10.4.0`) orchestrated by **Nx**. Four workspace packages:
 | `apps/client` | `client` | React 18 + Vite + Mantine 8 + TanStack Query + Jotai | SPA frontend |
 | `packages/editor-ext` | `@docmost/editor-ext` | Tiptap/ProseMirror | Shared Tiptap node/mark extensions, imported by both the client and the server |
 | `packages/mcp` | `@docmost/mcp` | MCP SDK, Tiptap, Yjs | Standalone MCP server, also bundled into the server at `/mcp`. Consumes the shared converter/schema from `@docmost/prosemirror-markdown` (#293) — it no longer carries its own vendored converter/schema copy |
-| `packages/prosemirror-markdown` | `@docmost/prosemirror-markdown` | Tiptap, marked, jsdom | The single, canonical ProseMirror↔Markdown converter + Docmost schema mirror (#293). Consumed by `mcp` and `git-sync`; there is exactly ONE copy of the converter now |
+| `packages/prosemirror-markdown` | `@docmost/prosemirror-markdown` | Tiptap, marked, jsdom | The single, canonical ProseMirror↔Markdown converter + Docmost schema mirror (#293). Consumed by `mcp`, `git-sync`, AND `apps/server` (server-side markdown import/export, #345); there is exactly ONE copy of the converter now |
 
 `build` targets are Nx-cached and dependency-ordered (`dependsOn: ["^build"]`), so `editor-ext` builds before the apps. `nx.json` sets `affected.defaultBase: main`.
 
@@ -284,7 +284,7 @@ The API server is a Fastify app with a global `/api` prefix (`main.ts` excludes
 ### Client structure
 Vite SPA. Code is organized by feature under `apps/client/src/features/*` (mirrors the server domains: `page`, `space`, `comment`, `ai-chat`, `editor`, …). Conventions:
 - **TanStack Query** for server state (one `queries/` file per feature), **Jotai** atoms for local/shared UI state, **Mantine 8** + CSS modules (`*.module.css`) + `postcss-preset-mantine` for UI.
-- The editor is Tiptap; shared node/mark extensions live in `packages/editor-ext` and are imported by **both the client and the server** (collaboration, import/export) — editor schema changes often need to be made in `editor-ext`, not just the client. The ProseMirror↔Markdown converter and its Docmost schema mirror now live in a SINGLE package, `@docmost/prosemirror-markdown` (#293), consumed by both `mcp` and `git-sync` — do NOT reintroduce a per-package copy. `editor-ext` is the upstream source of the Tiptap schema; the package's `docmost-schema.ts` mirrors it and a serializer-contract test (`packages/prosemirror-markdown/test/serializer-contract.test.ts`) guards the boundary (every schema node must have a converter case), so a drift surfaces as a failing test rather than silent divergence.
+- The editor is Tiptap; shared node/mark extensions live in `packages/editor-ext` and are imported by **both the client and the server** (collaboration, schema, `canonicalizeFootnotes`) — editor schema changes often need to be made in `editor-ext`, not just the client. Server-side markdown import/export no longer lives in `editor-ext`: it goes through the canonical converter (#345, see below). The ProseMirror↔Markdown converter and its Docmost schema mirror now live in a SINGLE package, `@docmost/prosemirror-markdown` (#293), consumed by `mcp`, `git-sync`, and `apps/server` (#345) — do NOT reintroduce a per-package copy. `editor-ext` is the upstream source of the Tiptap schema; the package's `docmost-schema.ts` mirrors it and a serializer-contract test (`packages/prosemirror-markdown/test/serializer-contract.test.ts`) guards the boundary (every schema node must have a converter case), so a drift surfaces as a failing test rather than silent divergence.
 - API access goes through `apps/client/src/lib/api-client.ts` (axios). The `@` alias maps to `apps/client/src`.
 - Runtime config is injected at build time by `vite.config.ts` via `define` (`APP_URL`, `COLLAB_URL`, `APP_VERSION`, …) — these come from the root `.env`, not from `import.meta.env`.
 

apps/server/package.json

@@ -23,7 +23,7 @@
     "migration:reset": "tsx src/database/migrate.ts down-to NO_MIGRATIONS",
     "migration:codegen": "kysely-codegen --dialect=postgres --camel-case --env-file=../../.env --out-file=./src/database/types/db.d.ts",
     "lint": "eslint \"{src,apps,libs,test}/**/*.ts\" --fix",
-    "pretest": "pnpm --filter @docmost/editor-ext build",
+    "pretest": "pnpm --filter @docmost/editor-ext build && pnpm --filter @docmost/prosemirror-markdown build",
     "test": "jest",
     "test:int": "jest --config test/jest-integration.json",
     "test:watch": "jest --watch",
@@ -43,6 +43,7 @@
     "@clickhouse/client": "^1.18.2",
     "@docmost/mcp": "workspace:*",
     "@docmost/pdf-inspector": "1.9.6",
+    "@docmost/prosemirror-markdown": "workspace:*",
     "@fastify/cookie": "^11.0.2",
     "@fastify/multipart": "^10.0.0",
     "@fastify/static": "^9.1.3",
@@ -175,7 +176,7 @@
       "/node_modules/"
     ],
     "transform": {
-      "happy-dom.+\\.js$": [
+      "(happy-dom.+|prosemirror-markdown/build/.+)\\.js$": [
         "babel-jest",
         {
           "presets": [
@@ -193,7 +194,7 @@
       "^.+\\.(t|j)sx?$": "ts-jest"
     },
     "transformIgnorePatterns": [
-      "/node_modules/(?!(\\.pnpm/)?(nanoid|uuid|image-dimensions|marked|happy-dom|lib0)(@|/))"
+      "/node_modules/(?!(\\.pnpm/)?(nanoid|uuid|image-dimensions|marked|happy-dom|lib0|@docmost/prosemirror-markdown)(@|/))"
     ],
     "collectCoverageFrom": [
       "**/*.(t|j)s"
@@ -204,7 +205,8 @@
       "^@docmost/db/(.*)$": "<rootDir>/database/$1",
       "^@docmost/transactional/(.*)$": "<rootDir>/integrations/transactional/$1",
       "^@docmost/ee/(.*)$": "<rootDir>/ee/$1",
-      "^src/(.*)$": "<rootDir>/$1"
+      "^src/(.*)$": "<rootDir>/$1",
+      "^@tiptap/react$": "<rootDir>/../test/stubs/tiptap-react.js"
     }
   }
 }

apps/server/src/collaboration/collaboration.util.ts

@@ -43,7 +43,6 @@ import {
   Column,
   Status,
   addUniqueIdsToDoc,
-  htmlToMarkdown,
   TransclusionSource,
   TransclusionReference,
   FootnoteReference,
@@ -51,6 +50,7 @@ import {
   FootnoteDefinition,
   PageEmbed,
 } from '@docmost/editor-ext';
+import { convertProseMirrorToMarkdown } from '@docmost/prosemirror-markdown';
 import { generateText, getSchema, JSONContent } from '@tiptap/core';
 import { generateHTML, generateJSON } from '../common/helpers/prosemirror/html';
 // @tiptap/html library works best for generating prosemirror json state but not HTML
@@ -239,6 +239,10 @@ export function prosemirrorNodeToYElement(node: any): Y.XmlElement | Y.XmlText {
 }
 
 export function jsonToMarkdown(tiptapJson: any): string {
-  const html = jsonToHtml(tiptapJson);
-  return htmlToMarkdown(html);
+  // Direct ProseMirror JSON -> Markdown via the canonical converter
+  // (`@docmost/prosemirror-markdown`) — no HTML intermediate, no second
+  // editor-ext markdown layer. Same serializer as the page/space export and the
+  // git-sync vault writer, so every server PM->MD path emits identical canonical
+  // markdown (issue #345).
+  return convertProseMirrorToMarkdown(tiptapJson);
 }

apps/server/src/core/page/services/page.service.ts

@@ -52,7 +52,9 @@ import {
   INTERNAL_LINK_REGEX,
   extractPageSlugId,
 } from '../../../integrations/export/utils';
-import { markdownToHtml, canonicalizeFootnotes } from '@docmost/editor-ext';
+import { canonicalizeFootnotes } from '@docmost/editor-ext';
+import { markdownToProseMirror } from '@docmost/prosemirror-markdown';
+import { normalizeForeignMarkdown } from '../../../integrations/import/utils/foreign-markdown';
 import { WatcherService } from '../../watcher/watcher.service';
 import { sql } from 'kysely';
 import { TransclusionService } from '../transclusion/transclusion.service';
@@ -1301,8 +1303,14 @@ export class PageService {
 
     switch (format) {
       case 'markdown': {
-        const html = await markdownToHtml(content as string);
-        prosemirrorJson = htmlToJson(html as string);
+        // Canonical markdown -> ProseMirror JSON directly via
+        // `@docmost/prosemirror-markdown` (issue #345) — no HTML intermediate,
+        // no editor-ext markdown layer. Foreign markdown surfaces the strict
+        // parser rejects (GFM `[^id]` reference footnotes) are normalized to the
+        // canonical inline form first.
+        prosemirrorJson = await markdownToProseMirror(
+          normalizeForeignMarkdown(content as string),
+        );
         break;
       }
       case 'html': {

apps/server/src/integrations/export/export-markdown.spec.ts

@@ -0,0 +1,145 @@
+// export.service.ts imports the ESM-only @sindresorhus/slugify (not in jest's
+// transform allowlist). It is irrelevant to the markdown-serialization path under
+// test (only used for page-mention link slugs on the DB path), so it is mocked
+// out to keep the module graph loadable under ts-jest (mirrors the import specs).
+jest.mock('@sindresorhus/slugify', () => ({
+  __esModule: true,
+  default: (input: string) => String(input),
+}));
+
+import { convertProseMirrorToMarkdown } from '@docmost/prosemirror-markdown';
+import { ExportService } from './export.service';
+import { ExportFormat } from './dto/export-dto';
+
+/**
+ * STEP 1 golden test for issue #345: server MARKDOWN export runs DIRECTLY through
+ * the canonical converter (`convertProseMirrorToMarkdown`) — no HTML intermediate
+ * and no `@docmost/editor-ext` markdown layer — so the emitted markdown is in the
+ * canonical package forms and is byte-identical to the git-sync vault body.
+ *
+ * These are the goldens the swap has to satisfy: they assert the CANONICAL
+ * surface (callout `> [!type]`, inline footnote `^[…]`, lossless image
+ * `<!--img …-->`) rather than the old editor-ext forms (`:::type`, `[^id]`,
+ * lossy `![alt](src)`).
+ *
+ * `exportPage(..., singlePage=false)` takes no DB path (no mention rewriting), so
+ * the service is constructed with null collaborators and only the pure
+ * PM -> Markdown path is exercised.
+ */
+
+function makeService(): ExportService {
+  return new ExportService(
+    null as any, // pageRepo
+    null as any, // pagePermissionRepo
+    null as any, // db
+    null as any, // storageService
+    null as any, // environmentService
+    null as any, // domainService
+  );
+}
+
+// A representative page exercising the node types whose canonical markdown form
+// changed with the move off the editor-ext layer: callout, inline footnote, and a
+// lossless image carrying width/align attrs that the old layer dropped.
+const REPRESENTATIVE_DOC = {
+  type: 'doc',
+  content: [
+    {
+      type: 'paragraph',
+      content: [
+        { type: 'text', text: 'Body ' },
+        { type: 'footnoteReference', attrs: { id: 'fn-1' } },
+        { type: 'text', text: ' end.' },
+      ],
+    },
+    {
+      type: 'callout',
+      attrs: { type: 'info', icon: null },
+      content: [
+        {
+          type: 'paragraph',
+          content: [{ type: 'text', text: 'Heads up' }],
+        },
+      ],
+    },
+    {
+      type: 'image',
+      attrs: {
+        src: '/files/pic.png',
+        alt: 'Pic',
+        width: 320,
+        align: 'left',
+      },
+    },
+    {
+      type: 'footnotesList',
+      content: [
+        {
+          type: 'footnoteDefinition',
+          attrs: { id: 'fn-1' },
+          content: [
+            {
+              type: 'paragraph',
+              content: [{ type: 'text', text: 'the note' }],
+            },
+          ],
+        },
+      ],
+    },
+  ],
+};
+
+describe('ExportService — markdown export via the canonical converter (#345)', () => {
+  it('emits canonical callout, inline footnote and lossless image forms', async () => {
+    const service = makeService();
+    const md = (await service.exportPage(ExportFormat.Markdown, {
+      title: '',
+      content: REPRESENTATIVE_DOC,
+    } as any)) as string;
+
+    // Callout: Obsidian `> [!type]`, NOT the legacy `:::type`.
+    expect(md).toContain('> [!info]');
+    expect(md).not.toContain(':::');
+
+    // Inline footnote: `^[…]`, NOT the reference `[^id]` form.
+    expect(md).toContain('^[the note]');
+    expect(md).not.toMatch(/\[\^/);
+
+    // Lossless image: trailing `<!--img …-->` carrying the dropped attrs.
+    expect(md).toContain('![Pic](/files/pic.png)');
+    expect(md).toContain('<!--img');
+    expect(md).toContain('"width":"320"');
+    expect(md).toContain('"align":"left"');
+  });
+
+  it('export body is byte-identical to the git-sync vault serializer (export == vault)', async () => {
+    const service = makeService();
+    // A title-less page: exportPage prepends NO heading, so the whole output is
+    // the page BODY — exactly what git-sync serializes (git-sync stores the title
+    // in frontmatter / the filename, never as an in-body H1).
+    const exported = (await service.exportPage(ExportFormat.Markdown, {
+      title: '',
+      content: REPRESENTATIVE_DOC,
+    } as any)) as string;
+
+    // The git-sync vault writer feeds this SAME converter (git-sync
+    // `stabilizePageBody` = convertProseMirrorToMarkdown(content) at the
+    // fixpoint). For an already-stable doc the single pass IS the fixpoint, so
+    // the two are byte-identical by construction — assert it.
+    const vaultBody = convertProseMirrorToMarkdown(REPRESENTATIVE_DOC);
+    expect(exported).toBe(vaultBody);
+  });
+
+  it('prepends the page title as an H1 heading (the one documented export/vault delta)', async () => {
+    const service = makeService();
+    const md = (await service.exportPage(ExportFormat.Markdown, {
+      title: 'My Page',
+      content: { type: 'doc', content: [] },
+    } as any)) as string;
+
+    // Export makes standalone files, so it prepends the title as an H1. This is
+    // the ONE deliberate difference from the vault body (which carries the title
+    // in frontmatter). The body below the heading still serializes canonically.
+    expect(md.startsWith('# My Page')).toBe(true);
+  });
+});

apps/server/src/integrations/export/export.service.ts

@@ -37,7 +37,7 @@ import {
   getAttachmentIds,
   getProsemirrorContent,
 } from '../../common/helpers/prosemirror/utils';
-import { htmlToMarkdown } from '@docmost/editor-ext';
+import { convertProseMirrorToMarkdown } from '@docmost/prosemirror-markdown';
 
 type AllowedAttachment = { id: string; fileName: string; filePath: string };
 
@@ -79,9 +79,8 @@ export class ExportService {
       prosemirrorJson.content.unshift(titleNode);
     }
 
-    const pageHtml = jsonToHtml(prosemirrorJson);
-
     if (format === ExportFormat.HTML) {
+      const pageHtml = jsonToHtml(prosemirrorJson);
       return `<!DOCTYPE html>
       <html>
         <head>
@@ -92,11 +91,14 @@ export class ExportService {
     }
 
     if (format === ExportFormat.Markdown) {
-      const newPageHtml = pageHtml.replace(
-        /<colgroup[^>]*>[\s\S]*?<\/colgroup>/gim,
-        '',
-      );
-      return htmlToMarkdown(newPageHtml);
+      // Direct ProseMirror JSON -> Markdown via the canonical converter
+      // (`@docmost/prosemirror-markdown`). This is the SAME serializer the
+      // git-sync vault writer feeds (see git-sync `stabilizePageBody`), so an
+      // exported page body is byte-identical to its vault representation — no
+      // HTML intermediate, no second markdown layer, no format drift (issue
+      // #345). The old `<colgroup>` scrub is gone with the HTML step: the
+      // converter emits GFM tables directly and never produces `<colgroup>`.
+      return convertProseMirrorToMarkdown(prosemirrorJson);
     }
 
     return;

apps/server/src/integrations/import/services/file-import-task.service.footnote-canonicalize.spec.ts

@@ -17,6 +17,22 @@ jest.mock('image-dimensions', () => ({
   __esModule: true,
   imageDimensionsFromData: () => undefined,
 }));
+// FileImportTaskService -> PageService -> collaboration.gateway ->
+// metrics.registry imports `prom-client`, which is not resolvable in this
+// workspace's node_modules (types-only stub, no runtime entry). Metrics are
+// disabled on this path, so a virtual no-op mock keeps the module graph loadable.
+jest.mock(
+  'prom-client',
+  () => ({
+    collectDefaultMetrics: () => undefined,
+    Registry: class {},
+    Histogram: class {},
+    Gauge: class {},
+    Counter: class {},
+    Summary: class {},
+  }),
+  { virtual: true },
+);
 
 import { promises as fs } from 'fs';
 import * as os from 'os';
@@ -26,14 +42,17 @@ import { ImportService } from './import.service';
 
 /**
  * Binding test for issue #228 / review #5: FileImportTaskService.processGenericImport
- * is a NON-editor write path (markdownToHtml -> processHTML -> JSON, never runs
- * footnoteSyncPlugin), so it canonicalizes footnotes before persisting. This pins
- * that binding — the same one import.service has a spec for — which previously had
- * NO spec at all.
+ * is a NON-editor write path, so a zip-imported `.md` page ends up with canonical
+ * footnotes before persisting: ordered by first reference, reused refs deduped,
+ * orphan definitions dropped.
  *
- * The markdown -> HTML -> ProseMirror conversion is REAL (a real ImportService,
- * its createYdoc stubbed); the filesystem is a real temp dir with one .md file;
- * the DB transaction is stubbed to capture the persisted page content.
+ * Since #345 the `.md` parse runs `normalizeForeignMarkdown` ->
+ * `markdownToProseMirror` -> `jsonToHtml` (feeding the shared HTML attachment /
+ * link pipeline) -> `processHTML` -> `canonicalizeFootnotes`. The parser assigns
+ * fresh `fn-*` ids, so we assert by definition BODY order rather than the source
+ * labels. The conversion is REAL (a real ImportService, its createYdoc stubbed);
+ * the filesystem is a real temp dir with one .md file; the DB transaction is
+ * stubbed to capture the persisted page content.
  */
 
 // Out-of-order references (c, a, b), a REUSED reference ([^a] twice), and an
@@ -49,13 +68,14 @@ const MARKDOWN = [
   '[^z]: orphan note',
 ].join('\n');
 
-function footnoteListIds(content: any): string[] {
+/** Definition body texts of the (single) footnotesList, in list order. */
+function footnoteListBodies(content: any): string[] {
   const list = (content?.content ?? []).find(
     (n: any) => n.type === 'footnotesList',
   );
   return (list?.content ?? [])
     .filter((n: any) => n.type === 'footnoteDefinition')
-    .map((n: any) => n.attrs?.id);
+    .map((n: any) => n.content?.[0]?.content?.[0]?.text);
 }
 
 // A permissive chainable stub for the spaces lookup (selectFrom(...).select(...)
@@ -71,80 +91,127 @@ function chainable(result: any): any {
   return proxy;
 }
 
+/**
+ * Run one markdown file through the REAL zip-import pipeline
+ * (`processGenericImport` -> `markdownToProseMirror` -> `jsonToHtml` ->
+ * `processHTML`/`htmlToJson`) and return the persisted page `content`. This is
+ * the server-specific PM->HTML->PM hop that the package's own PM<->MD tests do
+ * NOT cover.
+ */
+async function runZipImport(markdown: string): Promise<any> {
+  const extractDir = await fs.mkdtemp(path.join(os.tmpdir(), 'fit-canon-'));
+  await fs.writeFile(path.join(extractDir, 'note.md'), markdown, 'utf-8');
+
+  const importService = new ImportService(
+    {} as any,
+    {} as any,
+    {} as any,
+    {} as any,
+  );
+  jest
+    .spyOn(importService as any, 'createYdoc')
+    .mockResolvedValue(Buffer.from([]) as any);
+
+  let captured: any = null;
+  const trx = {
+    insertInto: (table: string) => ({
+      values: (v: any) => {
+        if (table === 'pages') captured = v;
+        return { execute: async () => {} };
+      },
+    }),
+  };
+  const db: any = {
+    selectFrom: () => chainable({ slug: 'space-slug' }),
+    transaction: () => ({ execute: (fn: any) => fn(trx) }),
+  };
+
+  const importAttachmentService = {
+    processAttachments: async ({ html }: any) => html,
+  };
+  const service = new FileImportTaskService(
+    {} as any, // storageService
+    importService as any,
+    { nextPagePosition: async () => 'a0' } as any,
+    { insertBacklink: jest.fn() } as any,
+    db,
+    importAttachmentService as any,
+    { emit: jest.fn() } as any,
+    { logBatchWithContext: jest.fn() } as any,
+  );
+
+  const fileTask: any = {
+    id: 'task-1',
+    source: 'generic',
+    spaceId: 'space-1',
+    workspaceId: 'ws-1',
+    creatorId: 'user-1',
+  };
+
+  try {
+    await service.processGenericImport({ extractDir, fileTask });
+    expect(captured).toBeTruthy();
+    return captured.content;
+  } finally {
+    await fs.rm(extractDir, { recursive: true, force: true });
+  }
+}
+
+/** Find the first node of a given type anywhere in a PM content tree. */
+function findFirst(node: any, type: string): any {
+  if (!node || typeof node !== 'object') return null;
+  if (node.type === type) return node;
+  for (const child of node.content ?? []) {
+    const hit = findFirst(child, type);
+    if (hit) return hit;
+  }
+  return null;
+}
+
 describe('FileImportTaskService.processGenericImport — footnote canonicalization (#228)', () => {
   it('orders footnotes by first reference, dedupes reuse, and drops orphans on zip import', async () => {
-    const extractDir = await fs.mkdtemp(path.join(os.tmpdir(), 'fit-canon-'));
-    await fs.writeFile(path.join(extractDir, 'note.md'), MARKDOWN, 'utf-8');
-
-    // Real ImportService for the html -> JSON conversion; stub the yjs encode.
-    const importService = new ImportService(
-      {} as any,
-      {} as any,
-      {} as any,
-      {} as any,
+    const content = await runZipImport(MARKDOWN);
+    // Definitions ordered by FIRST REFERENCE (C, A, B), NOT the markdown
+    // definition order (A, B, C). Ids are the parser's fresh `fn-*`, so pin
+    // the BODIES.
+    expect(footnoteListBodies(content)).toEqual(['note C', 'note A', 'note B']);
+    // Orphan [^z] dropped; reused [^a] collapses to one definition; one list.
+    expect(footnoteListBodies(content)).not.toContain('orphan note');
+    const lists = (content.content ?? []).filter(
+      (n: any) => n.type === 'footnotesList',
     );
-    jest
-      .spyOn(importService as any, 'createYdoc')
-      .mockResolvedValue(Buffer.from([]) as any);
+    expect(lists).toHaveLength(1);
+    expect(
+      footnoteListBodies(content).filter((b) => b === 'note A'),
+    ).toHaveLength(1);
+  });
 
-    let captured: any = null;
-    const trx = {
-      insertInto: (table: string) => ({
-        values: (v: any) => {
-          if (table === 'pages') captured = v;
-          return { execute: async () => {} };
-        },
-      }),
-    };
-    const db: any = {
-      selectFrom: () => chainable({ slug: 'space-slug' }),
-      transaction: () => ({ execute: (fn: any) => fn(trx) }),
-    };
+  // #345 F4: the zip path routes markdown through jsonToHtml -> processHTML ->
+  // htmlToJson (the shared HTML attachment pipeline). #345's headline is LOSSLESS
+  // image width/align via the `<!--img {...}-->` comment; a callout carries its
+  // `type`. This asserts those survive the PM->HTML->PM hop — the one hop the
+  // package's PM<->MD suite does not exercise.
+  it('preserves image width/align and callout type through the PM->HTML->PM hop', async () => {
+    const md = [
+      '# Doc',
+      '',
+      '![a picture](https://example.com/i.png) <!--img {"width":"320","align":"left"}-->',
+      '',
+      ':::warning',
+      'Careful now.',
+      ':::',
+    ].join('\n');
 
-    const importAttachmentService = {
-      processAttachments: async ({ html }: any) => html,
-    };
-    const backlinkRepo = { insertBacklink: jest.fn() };
-    const eventEmitter = { emit: jest.fn() };
-    const auditService = { logBatchWithContext: jest.fn() };
+    const content = await runZipImport(md);
 
-    const pageService = { nextPagePosition: async () => 'a0' };
+    const image = findFirst(content, 'image');
+    expect(image).toBeTruthy();
+    // The lossless sizing/alignment must survive the HTML hop.
+    expect(String(image.attrs?.width)).toBe('320');
+    expect(image.attrs?.align).toBe('left');
 
-    const service = new FileImportTaskService(
-      {} as any, // storageService
-      importService as any,
-      pageService as any,
-      backlinkRepo as any,
-      db,
-      importAttachmentService as any,
-      eventEmitter as any,
-      auditService as any,
-    );
-
-    const fileTask: any = {
-      id: 'task-1',
-      source: 'generic',
-      spaceId: 'space-1',
-      workspaceId: 'ws-1',
-      creatorId: 'user-1',
-    };
-
-    try {
-      await service.processGenericImport({ extractDir, fileTask });
-
-      expect(captured).toBeTruthy();
-      const content = captured.content;
-      // Reference order is c, a, b (NOT the markdown definition order a, b, c).
-      expect(footnoteListIds(content)).toEqual(['c', 'a', 'b']);
-      // Orphan [^z] dropped; reused [^a] collapses to one definition; one list.
-      expect(footnoteListIds(content)).not.toContain('z');
-      const lists = (content.content ?? []).filter(
-        (n: any) => n.type === 'footnotesList',
-      );
-      expect(lists).toHaveLength(1);
-      expect(footnoteListIds(content).filter((id) => id === 'a')).toHaveLength(1);
-    } finally {
-      await fs.rm(extractDir, { recursive: true, force: true });
-    }
+    const callout = findFirst(content, 'callout');
+    expect(callout).toBeTruthy();
+    expect(callout.attrs?.type).toBe('warning');
   });
 });

apps/server/src/integrations/import/services/file-import-task.service.ts

@@ -1,6 +1,9 @@
 import { Inject, Injectable, Logger } from '@nestjs/common';
 import * as path from 'path';
-import { jsonToText } from '../../../collaboration/collaboration.util';
+import {
+  jsonToHtml,
+  jsonToText,
+} from '../../../collaboration/collaboration.util';
 import { InjectKysely } from 'nestjs-kysely';
 import { KyselyDB } from '@docmost/db/types/kysely.types';
 import {
@@ -18,9 +21,11 @@ import { generateSlugId } from '../../../common/helpers';
 import { v7 } from 'uuid';
 import { generateJitteredKeyBetween } from 'fractional-indexing-jittered';
 import { FileTask, InsertablePage } from '@docmost/db/types/entity.types';
-import { markdownToHtml, canonicalizeFootnotes } from '@docmost/editor-ext';
+import { canonicalizeFootnotes } from '@docmost/editor-ext';
+import { markdownToProseMirror } from '@docmost/prosemirror-markdown';
 import { getProsemirrorContent } from '../../../common/helpers/prosemirror/utils';
 import { formatImportHtml } from '../utils/import-formatter';
+import { normalizeForeignMarkdown } from '../utils/foreign-markdown';
 import {
   buildAttachmentCandidates,
   collectMarkdownAndHtmlFiles,
@@ -461,7 +466,18 @@ export class FileImportTaskService {
               content = await fs.readFile(absPath, 'utf-8');
 
               if (page.fileExtension.toLowerCase() === '.md') {
-                content = await markdownToHtml(content);
+                // Parse markdown with the single canonical converter
+                // (`@docmost/prosemirror-markdown`), after normalizing foreign
+                // reference footnotes, then serialize to HTML so the shared HTML
+                // pipeline below (processAttachments + formatImportHtml +
+                // processHTML) keeps handling `.md` and `.html` imports
+                // uniformly. The markdown PARSE no longer goes through the
+                // editor-ext markdown layer (issue #345) — the drift source is
+                // gone. The PM -> HTML -> PM hop that follows is lossless
+                // plumbing for attachment/link resolution, NOT a second parse.
+                content = jsonToHtml(
+                  await markdownToProseMirror(normalizeForeignMarkdown(content)),
+                );
               }
             } catch (err: any) {
               if (err?.code === 'ENOENT') {
@@ -500,10 +516,12 @@ export class FileImportTaskService {
               this.importService.extractTitleAndRemoveHeading(pmState);
 
             // Canonicalize footnote topology on this non-editor write path
-            // (markdownToHtml/processHTML never runs footnoteSyncPlugin), so a
-            // zip-imported page's footnotes are reference-ordered, deduped, and
+            // (the HTML pipeline's processHTML never runs footnoteSyncPlugin), so
+            // a zip-imported page's footnotes are reference-ordered, deduped, and
             // orphan-free like the editor's invariant (issue #228). Pure +
-            // idempotent + shape-safe; a footnote-free doc is unchanged.
+            // idempotent + shape-safe; a footnote-free doc is unchanged. (For a
+            // `.md` file the package parser already yields canonical footnotes,
+            // so this is a no-op there.)
             // (Future consolidation, architecture B: like import.service, this
             // path persists directly rather than via PageService — a shared
             // "prepare JSON for persist" helper would centralize this call.)

apps/server/src/integrations/import/services/import.service.footnote-canonicalize.spec.ts

@@ -12,13 +12,19 @@ import { canonicalizeFootnotes } from '@docmost/editor-ext';
 
 /**
  * Integration-ish test for the USER-FACING markdown import path
- * (`ImportService.importPage`). It exercises the REAL markdown -> HTML -> JSON
- * conversion and asserts that the stored page content has its footnotes
- * canonicalized — the gap that issue #228 fixes: the import path builds
- * ProseMirror JSON directly (never running the editor's footnoteSyncPlugin), so
- * before this wiring the stored footnotes kept the markdown's physical
- * definition order (out of order vs. references), retained orphan definitions,
- * and did not collapse reused references.
+ * (`ImportService.importPage`). It exercises the REAL markdown -> ProseMirror
+ * conversion and asserts the stored page's footnotes are canonical: ordered by
+ * FIRST REFERENCE (not markdown definition order), reused references deduped to a
+ * single definition, and orphan definitions dropped.
+ *
+ * Since #345 the markdown parse runs through the canonical package
+ * (`normalizeForeignMarkdown` -> `markdownToProseMirror`), which owns this
+ * canonicalization: the input's GFM `[^id]` reference footnotes are normalized to
+ * inline `^[…]`, and the parser assigns fresh sequential ids (`fn-*`) in
+ * reference order while merging identical bodies — so we assert by definition
+ * BODY order, not by the source labels. `canonicalizeFootnotes` remains wired as
+ * an idempotent safety net (issue #228) and is a no-op on this already-canonical
+ * output.
  *
  * The DB/ydoc side-effects are stubbed: `getNewPagePosition` (DB query) and
  * `createYdoc` (Yjs encode) are spied, and `pageRepo.insertPage` captures the
@@ -67,24 +73,14 @@ function makeService() {
 }
 
 /** List the footnote-definition ids of the (single) footnotesList, in order. */
-function footnoteListIds(content: any): string[] {
+/** Definition body texts of the (single) footnotesList, in list order. */
+function footnoteListBodies(content: any): string[] {
   const list = (content.content ?? []).find(
     (n: any) => n.type === 'footnotesList',
   );
-  if (!list) return [];
-  return (list.content ?? [])
+  return (list?.content ?? [])
     .filter((n: any) => n.type === 'footnoteDefinition')
-    .map((n: any) => n.attrs?.id);
-}
-
-function definitionText(content: any, id: string): string | undefined {
-  const list = (content.content ?? []).find(
-    (n: any) => n.type === 'footnotesList',
-  );
-  const def = (list?.content ?? []).find(
-    (n: any) => n.type === 'footnoteDefinition' && n.attrs?.id === id,
-  );
-  return def?.content?.[0]?.content?.[0]?.text;
+    .map((n: any) => n.content?.[0]?.content?.[0]?.text);
 }
 
 describe('ImportService.importPage — footnote canonicalization (#228)', () => {
@@ -101,23 +97,23 @@ describe('ImportService.importPage — footnote canonicalization (#228)', () =>
     const content = getCaptured().content;
     expect(content).toBeTruthy();
 
-    // Reference order is c, a, b (NOT the markdown definition order a, b, c).
-    expect(footnoteListIds(content)).toEqual(['c', 'a', 'b']);
-
-    // Definitions preserved and attached to the right ids.
-    expect(definitionText(content, 'c')).toBe('note C');
-    expect(definitionText(content, 'a')).toBe('note A');
-    expect(definitionText(content, 'b')).toBe('note B');
+    // Definitions ordered by FIRST REFERENCE (C, A, B) — NOT the markdown
+    // definition order (A, B, C) — with the orphan [^z] dropped and the reused
+    // [^a] collapsed to a single definition. (Ids are the parser's fresh `fn-*`,
+    // so we pin the BODIES.)
+    expect(footnoteListBodies(content)).toEqual(['note C', 'note A', 'note B']);
 
     // Orphan definition [^z] is dropped.
-    expect(footnoteListIds(content)).not.toContain('z');
+    expect(footnoteListBodies(content)).not.toContain('orphan note');
 
     // Reused [^a] yields exactly ONE definition, and exactly one list.
     const lists = (content.content ?? []).filter(
       (n: any) => n.type === 'footnotesList',
     );
     expect(lists).toHaveLength(1);
-    expect(footnoteListIds(content).filter((id) => id === 'a')).toHaveLength(1);
+    expect(
+      footnoteListBodies(content).filter((b) => b === 'note A'),
+    ).toHaveLength(1);
   });
 
   it('is idempotent: canonicalizing the stored output again is a no-op', async () => {
@@ -134,6 +130,6 @@ describe('ImportService.importPage — footnote canonicalization (#228)', () =>
     // time must not change it (safe to wire into every write path).
     const second = canonicalizeFootnotes(stored);
     expect(second).toEqual(stored);
-    expect(footnoteListIds(second)).toEqual(['c', 'a', 'b']);
+    expect(footnoteListBodies(second)).toEqual(['note C', 'note A', 'note B']);
   });
 });

apps/server/src/integrations/import/services/import.service.ts

@@ -17,7 +17,9 @@ import {
 import { generateJitteredKeyBetween } from 'fractional-indexing-jittered';
 import { TiptapTransformer } from '@hocuspocus/transformer';
 import * as Y from 'yjs';
-import { markdownToHtml, canonicalizeFootnotes } from '@docmost/editor-ext';
+import { canonicalizeFootnotes } from '@docmost/editor-ext';
+import { markdownToProseMirror } from '@docmost/prosemirror-markdown';
+import { normalizeForeignMarkdown } from '../utils/foreign-markdown';
 import {
   FileTaskStatus,
   FileTaskType,
@@ -85,11 +87,13 @@ export class ImportService {
 
     const extracted = this.extractTitleAndRemoveHeading(prosemirrorState);
     const title = extracted.title;
-    // Imported markdown/HTML is built via markdownToHtml -> htmlToJson, which
-    // never runs the editor's footnoteSyncPlugin, so the footnote topology keeps
-    // the source's PHYSICAL definition order (out of order vs. references),
-    // retains orphan definitions, and is not deduped. Canonicalize before
-    // persisting so the stored page matches the editor's invariant (issue #228).
+    // The markdown path now canonicalizes footnotes itself (the package parser),
+    // but the HTML path (processHTML -> htmlToJson) does NOT run the editor's
+    // footnoteSyncPlugin, so an imported HTML doc can keep its source's PHYSICAL
+    // definition order (out of order vs. references), retain orphan definitions,
+    // and not be deduped. Canonicalize before persisting so the stored page
+    // matches the editor's invariant (issue #228); it is an idempotent no-op on
+    // the already-canonical markdown output.
     // Pure + idempotent + shape-safe: a doc with no footnotes is unchanged.
     // (Future consolidation, architecture B: this import path persists directly
     // via pageRepo.insertPage rather than through PageService.createPage, so the
@@ -133,12 +137,15 @@ export class ImportService {
   }
 
   async processMarkdown(markdownInput: string): Promise<any> {
-    try {
-      const html = await markdownToHtml(markdownInput);
-      return this.processHTML(html);
-    } catch (err) {
-      throw err;
-    }
+    // Canonical markdown -> ProseMirror JSON directly via
+    // `@docmost/prosemirror-markdown` (issue #345) — no HTML intermediate and no
+    // second editor-ext markdown layer. Foreign markdown surfaces the strict
+    // canonical parser does not accept (GFM `[^id]` reference footnotes) are
+    // rewritten to the canonical inline form by `normalizeForeignMarkdown` first.
+    // The HTML-cleanup pass (`normalizeImportHtml`) is intentionally skipped here:
+    // it targets foreign *HTML* (Notion/XWiki), which only ever arrives on the
+    // `.html` path (`processHTML`), never as canonical markdown.
+    return markdownToProseMirror(normalizeForeignMarkdown(markdownInput));
   }
 
   async processHTML(htmlInput: string): Promise<any> {

apps/server/src/integrations/import/utils/foreign-markdown.spec.ts

@@ -0,0 +1,218 @@
+import {
+  convertProseMirrorToMarkdown,
+  markdownToProseMirror,
+} from '@docmost/prosemirror-markdown';
+import { normalizeForeignMarkdown } from './foreign-markdown';
+
+/**
+ * STEP 2 goldens for issue #345: the foreign-markdown normalizer that runs at the
+ * import boundary BEFORE the strict canonical parser (`markdownToProseMirror`).
+ *
+ * Two layers:
+ *  1. PURE string→string cases pinning the normalizer's own behavior (GFM
+ *     reference footnotes → inline `^[…]`).
+ *  2. END-TO-END acceptance: for a foreign corpus, `normalizeForeignMarkdown`
+ *     then `markdownToProseMirror` then `convertProseMirrorToMarkdown` must leave
+ *     NO literal `[^id]` / `:::` garbage in the document and must re-export in the
+ *     canonical forms.
+ */
+
+describe('normalizeForeignMarkdown — GFM reference footnotes', () => {
+  it('inlines a single-line reference footnote and drops its definition', () => {
+    const out = normalizeForeignMarkdown(
+      'A note[^1] here.\n\n[^1]: The definition.',
+    );
+    expect(out).toBe('A note^[The definition.] here.\n');
+  });
+
+  it('inlines every reference to a reused id (downstream dedups)', () => {
+    const out = normalizeForeignMarkdown(
+      'X[^a] and Y[^a].\n\n[^a]: shared.',
+    );
+    expect(out).toBe('X^[shared.] and Y^[shared.].\n');
+  });
+
+  it('joins indented continuation lines of a definition with a space', () => {
+    const out = normalizeForeignMarkdown(
+      'See[^n].\n\n[^n]: line one\n    line two',
+    );
+    expect(out).toBe('See^[line one line two].\n');
+  });
+
+  it('never rewrites a reference inside a fenced code block', () => {
+    const out = normalizeForeignMarkdown(
+      '```\ncode[^1] here\n```\n\n[^1]: def.',
+    );
+    expect(out).toContain('code[^1] here');
+    // The (now orphaned) definition line is still removed.
+    expect(out).not.toContain('[^1]: def.');
+  });
+
+  it('never rewrites a reference inside an INLINE-code span (backticks)', () => {
+    // The `[^1]` inside backticks is literal code and must survive verbatim;
+    // the one outside is rewritten. (Bug #1: only fenced blocks were protected.)
+    const out = normalizeForeignMarkdown(
+      'Use `arr[^1]` in code but note[^1] in prose.\n\n[^1]: def.',
+    );
+    expect(out).toBe('Use `arr[^1]` in code but note^[def.] in prose.\n');
+  });
+
+  it('escapes brackets in a body so an unbalanced ] cannot truncate the footnote', () => {
+    // A foreign definition body with a stray `]` would, unescaped, close the
+    // canonical `^[...]` early and leak the tail as text (bug #2). The body's
+    // brackets are backslash-escaped so the footnote stays whole.
+    const out = normalizeForeignMarkdown(
+      'Ref[^1] here.\n\n[^1]: see item ] and [more] later',
+    );
+    expect(out).toBe('Ref^[see item \\] and \\[more\\] later] here.\n');
+    // The tokenizer must see exactly one unescaped closing bracket (our own).
+    expect(out.match(/(?<!\\)\]/g)).toHaveLength(1);
+  });
+
+  it('leaves a reference with no matching definition literal (no body to inline)', () => {
+    const out = normalizeForeignMarkdown('Dangling[^x] ref.');
+    expect(out).toBe('Dangling[^x] ref.');
+  });
+
+  it('returns the input unchanged when there are no reference footnotes', () => {
+    const md = '# Title\n\nJust text with `inline code` and a [link](/x).';
+    expect(normalizeForeignMarkdown(md)).toBe(md);
+  });
+
+  it('does NOT touch callout surfaces — the canonical parser handles them', () => {
+    const callouts = ':::info\nHi\n:::\n\n> [!warning]\n> Careful';
+    expect(normalizeForeignMarkdown(callouts)).toBe(callouts);
+  });
+
+  it('strips a leading YAML front-matter block (Obsidian/Hugo/git-sync files)', () => {
+    const out = normalizeForeignMarkdown(
+      '---\ntitle: My Page\ntags: [a, b]\n---\n\n# Heading\n\nBody.',
+    );
+    expect(out).toBe('# Heading\n\nBody.');
+    // The front-matter must not leak into the body as a setext heading.
+    expect(out).not.toContain('title: My Page');
+    expect(out).not.toContain('---');
+  });
+
+  it('does not strip a horizontal rule that is not leading front-matter', () => {
+    const md = 'Intro paragraph.\n\n---\n\nAfter the rule.';
+    expect(normalizeForeignMarkdown(md)).toBe(md);
+  });
+
+  it('is linear on a document with thousands of definitions (no quadratic blowup)', () => {
+    // F2(a): the pass-2 rewrite must be O(text), not O(text × defs). Build a
+    // pathological doc (many defs + many plain text lines) and assert it
+    // completes well under a second — a quadratic implementation took ~14s.
+    const N = 4000;
+    const refs = Array.from({ length: N }, (_, i) => `line ${i} plain text`).join('\n');
+    const defs = Array.from({ length: N }, (_, i) => `[^n${i}]: def ${i}`).join('\n');
+    const doc = `start[^n0] and[^n${N - 1}] end\n\n${refs}\n\n${defs}`;
+    const t0 = Date.now();
+    const out = normalizeForeignMarkdown(doc);
+    const elapsed = Date.now() - t0;
+    expect(elapsed).toBeLessThan(2000);
+    // Sanity: the two real references were still inlined.
+    expect(out).toContain('^[def 0]');
+    expect(out).toContain(`^[def ${N - 1}]`);
+  });
+
+  it('is bounded on a long unclosed backtick run (no inline-split ReDoS)', () => {
+    // F2(b): a huge unterminated backtick run must not cause quadratic
+    // backtracking in the inline-code split. Oversized lines skip the split
+    // entirely (left untouched), so this returns promptly.
+    const line = 'x' + '`'.repeat(200000);
+    const doc = `${line}\n\n[^1]: def`;
+    const t0 = Date.now();
+    normalizeForeignMarkdown(doc);
+    expect(Date.now() - t0).toBeLessThan(2000);
+  });
+
+  it('does not crash or slow down on thousands of prefix-chain definition ids', () => {
+    // F7: the rewrite must use a FIXED generic scanner, not an alternation built
+    // from the ids. A `(a|aa|aaa|…)` alternation over prefix-chain ids blows the
+    // V8 regex compiler (FATAL RegExpCompiler Allocation failed — uncatchable,
+    // kills the process). A fixed scanner has no id-dependent compilation cost.
+    const N = 4000;
+    const ids = Array.from({ length: N }, (_, i) => 'a'.repeat(i + 1));
+    const defs = ids.map((id) => `[^${id}]: body ${id.length}`).join('\n');
+    const doc = `ref[^${ids[0]}] and[^${ids[N - 1]}] end\n\n${defs}`;
+    const t0 = Date.now();
+    const out = normalizeForeignMarkdown(doc);
+    expect(Date.now() - t0).toBeLessThan(2000);
+    // Prefix disambiguation is correct: [^a] and [^aaaa...] inline their OWN body.
+    expect(out).toContain('^[body 1]');
+    expect(out).toContain(`^[body ${N}]`);
+  });
+
+  it('strips a CRLF (Windows) front-matter block, not just LF', () => {
+    // F9: the line-anchored regex needs LF after the opening `---`, so a Windows
+    // file (`---\r\n…`) would slip past the strip and leak the front-matter into
+    // the body. normalizeForeignMarkdown normalizes CRLF -> LF first.
+    const out = normalizeForeignMarkdown(
+      '---\r\ntitle: Foo\r\ntags: [a]\r\n---\r\n\r\n# Heading\r\n\r\nBody.',
+    );
+    expect(out).toBe('# Heading\n\nBody.');
+    expect(out).not.toContain('title: Foo');
+    expect(out).not.toContain('---');
+  });
+
+  it('strips front-matter whose value contains a triple-dash (line-anchored)', () => {
+    // F8: the block must close only on a `\n---` LINE, not the first inline
+    // `---`. A value like `title: Q1 --- Q2` must not truncate the front-matter
+    // and leak the rest (author/closing ---) into the body.
+    const out = normalizeForeignMarkdown(
+      '---\ntitle: Q1 --- Q2 results\nauthor: bob\n---\n\nReal body.',
+    );
+    expect(out).toBe('Real body.');
+    expect(out).not.toContain('author: bob');
+    expect(out).not.toContain('Q2 results');
+  });
+});
+
+describe('foreign markdown import acceptance (normalizer + canonical parser)', () => {
+  const FOREIGN = [
+    '# Doc',
+    '',
+    'Body refs [^c] and [^a] and [^b] and again [^a].',
+    '',
+    ':::info',
+    'A legacy callout.',
+    ':::',
+    '',
+    '| h1 | h2 |',
+    '| --- | --- |',
+    '| 1 | 2 |',
+    '',
+    '[^a]: note A',
+    '[^b]: note B',
+    '[^c]: note C',
+    '[^z]: orphan note',
+  ].join('\n');
+
+  it('leaves no literal [^id] or ::: in the imported doc and re-exports canonically', async () => {
+    const normalized = normalizeForeignMarkdown(FOREIGN);
+    const doc = await markdownToProseMirror(normalized);
+    const reexport = convertProseMirrorToMarkdown(doc);
+
+    // No foreign garbage leaks into the document.
+    expect(reexport).not.toMatch(/\[\^/); // no reference footnote refs/defs
+    expect(reexport).not.toContain(':::'); // no legacy callout fences
+
+    // Canonical forms are present.
+    expect(reexport).toContain('^[note C]');
+    expect(reexport).toContain('> [!info]');
+    expect(reexport).toContain('| h1 | h2 |');
+
+    // Footnotes: ordered by first reference (C, A, B), reused [^a] deduped to one,
+    // orphan [^z] dropped (it had no reference after normalization).
+    const list = doc.content.find((n: any) => n.type === 'footnotesList');
+    const bodies = list.content.map(
+      (d: any) => d.content[0].content[0].text,
+    );
+    expect(bodies).toEqual(['note C', 'note A', 'note B']);
+    expect(bodies).not.toContain('orphan note');
+    expect(
+      doc.content.filter((n: any) => n.type === 'footnotesList'),
+    ).toHaveLength(1);
+  });
+});

apps/server/src/integrations/import/utils/foreign-markdown.ts

@@ -0,0 +1,265 @@
+/**
+ * Foreign-markdown normalizer — an input-liberal / output-canonical adapter that
+ * runs at the IMPORT boundary, BEFORE the canonical parser
+ * (`markdownToProseMirror` from `@docmost/prosemirror-markdown`).
+ *
+ * The canonical parser is deliberately STRICT: it only understands Docmost's
+ * canonical markdown surface (Obsidian-style `> [!type]` callouts, Pandoc/Obsidian
+ * inline footnotes `^[body]`, lossless `![alt](src) <!--img {...}-->` images, …).
+ * Import, however, ingests FOREIGN files (GitHub/GFM, Notion, old Docmost
+ * exports). Those use surfaces the canonical parser does not accept, most notably
+ * GitHub-flavoured *reference* footnotes:
+ *
+ *     Text with a note[^1] and another[^long].
+ *
+ *     [^1]: The first definition.
+ *     [^long]: A second one.
+ *
+ * Left untouched, the parser does NOT recognise `[^id]` (it only parses `^[body]`),
+ * so the reference leaks as literal text — and worse, the trailing `[^id]: def`
+ * line is a valid CommonMark *link-reference definition*, so `[^id]` is silently
+ * rendered as a bogus link. This normalizer rewrites reference footnotes into the
+ * canonical inline form so the parser materialises real footnote nodes.
+ *
+ * This is a TEXT pre-pass, NOT a second parser fork: it does not re-implement any
+ * converter logic. Callout surfaces (`:::type` and `> [!type]`) are intentionally
+ * NOT touched here — the canonical parser already accepts BOTH natively (its
+ * `preprocessCallouts` pass), so normalizing them would be redundant and would
+ * only risk degrading the parser's nesting/code-fence-aware handling.
+ */
+
+/** Matches a fenced code block delimiter (``` or ~~~), capturing the marker run. */
+const CODE_FENCE_RE = /^(\s*)(`{3,}|~{3,})/;
+
+/**
+ * Matches a GFM footnote DEFINITION line: `[^id]: body`. The id is any run of
+ * non-`]` characters; the body is the remainder of the line (possibly empty).
+ */
+const FOOTNOTE_DEF_RE = /^\[\^([^\]]+)\]:[ \t]?(.*)$/;
+
+/** True when a line is a code-fence delimiter that toggles fenced-code state. */
+function fenceMarker(line: string): string | null {
+  const m = line.match(CODE_FENCE_RE);
+  return m ? m[2] : null;
+}
+
+/** True when a line is indented (leading space/tab) and not blank — a continuation. */
+function isIndentedContinuation(line: string): boolean {
+  return /^[ \t]+\S/.test(line);
+}
+
+function escapeRegExp(value: string): string {
+  return value.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+}
+
+/**
+ * Backslash-escape any square bracket in a footnote body before it is wrapped in
+ * `^[...]`. The canonical inline-footnote tokenizer scans the body with bracket
+ * balancing and closes on the first UNMATCHED `]`, so an unbalanced bracket in a
+ * foreign definition (e.g. `[^1]: see item ] later`) would otherwise truncate the
+ * footnote and leak the tail as literal text. Escaping every `[`/`]` makes the
+ * body an inert run of characters — the tokenizer then closes only on our own
+ * closing `]`. (A balanced `[link](url)` inside a body still round-trips because
+ * the escaped form renders the literal brackets, which is the safe reading for a
+ * footnote body; the alternative — brittle balance tracking — risks worse.)
+ */
+function escapeFootnoteBody(body: string): string {
+  return body.replace(/[[\]]/g, '\\$&');
+}
+
+/**
+ * Rewrite every `[^id]` reference on a line to its `^[body]` form, but ONLY in the
+ * text OUTSIDE inline-code spans. A `[^id]` inside backticks is literal code
+ * content and must be preserved verbatim (a footnote ref never lives inside code).
+ * We split the line on inline-code spans (paired backtick runs) and rewrite only
+ * the non-code segments.
+ */
+// Above this length a single line is not split into inline-code spans (see
+// below). A genuine markdown line carrying a footnote reference is never tens of
+// KB; the cap only bypasses the inline-code protection for pathological lines.
+const INLINE_SPLIT_MAX_LINE = 8192;
+
+function rewriteRefsOutsideInlineCode(
+  line: string,
+  replace: (text: string) => string,
+): string {
+  // The inline-code split alternation `(`+)(?:(?!\1)[\s\S])*\1` backtracks
+  // quadratically on a long UNCLOSED backtick run (its middle can consume the
+  // rest of the line, then fail to find a closing run and retry from each
+  // position). On an untrusted import this is a request-thread ReDoS. A real
+  // footnote line is short, so for an oversized line we skip the inline-code
+  // protection entirely and leave the line UNTOUCHED (rewriting it wholesale
+  // could corrupt a `[^id]` that legitimately lives inside inline code). This is
+  // a conservative bypass: an over-8KB line simply does not get its reference
+  // footnotes inlined — acceptable for a pathological input.
+  if (line.length > INLINE_SPLIT_MAX_LINE) return line;
+
+  // Alternation: an inline-code span (one or more backticks, then anything up to
+  // the SAME run of backticks) OR a run of non-backtick text. Unterminated
+  // backticks fall through as ordinary text (matched by the second branch on the
+  // leftover), so a stray backtick never swallows the rest of the line.
+  const parts = line.match(/(`+)(?:(?!\1)[\s\S])*\1|[^`]+|`+/g);
+  if (!parts) return line;
+  return parts
+    .map((seg) => (seg.startsWith('`') ? seg : replace(seg)))
+    .join('');
+}
+
+/**
+ * Convert GFM reference footnotes (`[^id]` + `[^id]: def`) into canonical inline
+ * footnotes (`^[def]`).
+ *
+ * - Definitions are collected first (a leading `[^id]: text` line plus any
+ *   immediately-following indented continuation lines, joined with a space) and
+ *   removed from the output.
+ * - Each in-text reference `[^id]` for which a definition was found is replaced by
+ *   `^[def]`. References with no matching definition are left literal (there is no
+ *   body to inline; the parser fails them open the same way).
+ * - Code is respected on both passes: `[^id]` inside a fenced ``` / ~~~ block is
+ *   never rewritten and a `[^id]:` line inside a fence is never a definition; and
+ *   on the rewrite pass a `[^id]` inside an INLINE-code span (backticks) is left
+ *   literal too.
+ * - The inlined body is bracket-escaped so an unbalanced `[`/`]` in a foreign
+ *   definition cannot truncate the resulting `^[...]` footnote.
+ *
+ * Deduplication / reference-ordering / orphan-dropping of the resulting footnotes
+ * is handled downstream by the canonical parser (`assembleFootnotes`); this pass
+ * only changes the surface syntax.
+ */
+function convertReferenceFootnotes(markdown: string): string {
+  const lines = markdown.split('\n');
+
+  // Pass 1: collect definitions and mark their lines for removal.
+  const defs = new Map<string, string>();
+  const dropped = new Array<boolean>(lines.length).fill(false);
+  let inFence = false;
+  let fence = '';
+
+  for (let i = 0; i < lines.length; i++) {
+    const line = lines[i];
+    const marker = fenceMarker(line);
+    if (inFence) {
+      if (marker && marker[0] === fence[0] && marker.length >= fence.length) {
+        inFence = false;
+        fence = '';
+      }
+      continue;
+    }
+    if (marker) {
+      inFence = true;
+      fence = marker;
+      continue;
+    }
+
+    const def = line.match(FOOTNOTE_DEF_RE);
+    if (!def) continue;
+
+    const id = def[1];
+    const body: string[] = [def[2].trim()];
+    dropped[i] = true;
+
+    // Consume immediately-following indented continuation lines (GFM lazy
+    // continuation is not supported by design — keep it simple and predictable).
+    let j = i + 1;
+    while (j < lines.length && isIndentedContinuation(lines[j])) {
+      body.push(lines[j].trim());
+      dropped[j] = true;
+      j++;
+    }
+    i = j - 1;
+
+    // Last definition wins for a duplicated id (matches CommonMark link-ref
+    // semantics closely enough for a foreign-input adapter).
+    defs.set(id, body.filter((s) => s.length > 0).join(' '));
+  }
+
+  if (defs.size === 0) {
+    return markdown;
+  }
+
+  // ONE fixed, generic scanner regex — NOT one built from the definition ids.
+  // It matches ANY `[^id]` shape, and the replacer decides per match via a map
+  // lookup whether that id is a real definition (replace) or not (leave as-is).
+  // This is genuinely O(total text) with no per-document regex compilation.
+  //
+  // Do NOT rebuild this as an alternation over `[...defs.keys()]`: a giant
+  // `(id1|id2|...)` alternation over thousands of ids can blow the V8 regex
+  // compiler's stack — a fatal, UNCATCHABLE "RegExpCompiler Allocation failed"
+  // on prefix-chain ids (`a`, `aa`, `aaa`, ...) that kills the whole process
+  // (worse than the earlier per-def thread-hang). A fixed scanner has no
+  // id-dependent compilation cost and cannot blow up.
+  const refRe = /\[\^([^\]]+)\]/g;
+  const rewriteSegment = (segment: string): string =>
+    segment.replace(refRe, (whole, id: string) => {
+      const body = defs.get(id);
+      // Only real definitions are inlined; an unknown id is left literal (same as
+      // the old per-def loop, which simply never matched it).
+      return body === undefined ? whole : `^[${escapeFootnoteBody(body)}]`;
+    });
+
+  // Pass 2: rewrite in-text references, skipping fenced code and dropped lines.
+  const out: string[] = [];
+  inFence = false;
+  fence = '';
+  for (let i = 0; i < lines.length; i++) {
+    if (dropped[i]) continue;
+    let line = lines[i];
+
+    const marker = fenceMarker(line);
+    if (inFence) {
+      out.push(line);
+      if (marker && marker[0] === fence[0] && marker.length >= fence.length) {
+        inFence = false;
+        fence = '';
+      }
+      continue;
+    }
+    if (marker) {
+      inFence = true;
+      fence = marker;
+      out.push(line);
+      continue;
+    }
+
+    line = rewriteRefsOutsideInlineCode(line, rewriteSegment);
+    out.push(line);
+  }
+
+  return out.join('\n');
+}
+
+/**
+ * Strip a single leading YAML front-matter block (`---\n…\n---`). Foreign files
+ * from Obsidian / Hugo / Jekyll / Notion — and Docmost's OWN git-sync page files
+ * — open with front-matter that the canonical parser does not consume, so
+ * without this it leaks into the body (and `title: Foo` above the closing `---`
+ * renders as a setext `<h2>` that `extractTitleAndRemoveHeading` can hijack as
+ * the page title). It is a no-op for front-matter-free input.
+ *
+ * LINE-ANCHORED (the same shape the canonical parser uses in
+ * prosemirror-markdown/page-file.ts): the block opens only on `---\n` at the
+ * very start and closes only on a `\n---` line. The retired `markdownToHtml`
+ * strip closed on the FIRST `---` ANYWHERE (an unanchored close), so a value
+ * containing a triple-dash (e.g. `title: Q1 --- Q2`) truncated the front-matter
+ * and leaked the rest into the body. An optional leading BOM is tolerated.
+ */
+const YAML_FRONT_MATTER_RE = /^\uFEFF?---\n[\s\S]*?\n---\n?/;
+
+/**
+ * Normalize a foreign markdown string into Docmost's canonical markdown surface
+ * so the strict canonical parser accepts it losslessly: normalize line endings,
+ * strip a leading YAML front-matter block, then rewrite GFM reference footnotes
+ * into inline footnotes. Add further fixture-driven foreign-surface cases here as
+ * they are found.
+ */
+export function normalizeForeignMarkdown(markdown: string): string {
+  if (!markdown) return markdown;
+  // Normalize CRLF -> LF FIRST. The line-anchored front-matter regex requires a
+  // bare `\n` after the opening `---`, and convertReferenceFootnotes splits on
+  // `\n`; a Windows/CRLF foreign file (`---\r\n…`) would otherwise slip past the
+  // front-matter strip and leak into the body. The canonical parser
+  // (page-file.ts parsePageFile) normalizes the same way before its FRONTMATTER_RE.
+  const src = markdown.replace(/\r\n/g, '\n');
+  const withoutFrontMatter = src.replace(YAML_FRONT_MATTER_RE, '').trimStart();
+  return convertReferenceFootnotes(withoutFrontMatter);
+}

apps/server/test/stubs/tiptap-react.js

@@ -0,0 +1,23 @@
+// Jest stub for @tiptap/react.
+//
+// The server export/import code paths transitively import editor-ext, whose node
+// extensions import from `@tiptap/react`. The real module re-exports all of
+// `@tiptap/core` (headless, safe under node) AND adds React view helpers
+// (`ReactNodeViewRenderer`, …) that eagerly pull in react-dom — which throws
+// `navigator is not defined` under jest's node environment.
+//
+// So this stub DELEGATES to the real `@tiptap/core` (keeping `mergeAttributes`,
+// `Node`, `Mark`, `nodeInputRule`, … working — they are used by
+// `jsonToHtml`/`htmlToJson` on the server) and overrides ONLY the React view
+// helpers with no-ops. Those helpers are referenced solely inside `addNodeView()`
+// — code that runs only in a live browser editor, never on the server; if any
+// were actually invoked here it would (correctly) surface as a test failure.
+const core = require('@tiptap/core');
+
+module.exports = {
+  ...core,
+  ReactNodeViewRenderer: () => () => ({}),
+  NodeViewWrapper: () => null,
+  NodeViewContent: () => null,
+  ReactRenderer: class {},
+};

pnpm-lock.yaml

@@ -543,6 +543,9 @@ importers:
       '@docmost/pdf-inspector':
         specifier: 1.9.6
         version: 1.9.6
+      '@docmost/prosemirror-markdown':
+        specifier: workspace:*
+        version: link:../../packages/prosemirror-markdown
       '@fastify/cookie':
         specifier: ^11.0.2
         version: 11.0.2