Human chat: combined media captions, composer drop, redaction & scroll

packages/core/src/matrix/__tests__/chat-markup.test.ts

@@ -6,6 +6,7 @@ import {
   matrixTextEventContentWithOptionalFormatting,
   parseChatMarkup,
 } from '../chat-markup';
+import { splitRichReplyPlainBody } from '../rich-reply';
 
 describe('chatMarkupLooksFormatted', () => {
   it('is false for plain text', () => {
@@ -44,4 +45,23 @@ describe('buildRichReplyMatrixContent', () => {
     expect(r.formatted_body).toContain('<strong>');
     expect(r.formatted_body).toContain('&lt;@u:h&gt;');
   });
+
+  /**
+   * Media edit with cleared caption but existing reply: matrix-provider passes a
+   * single space so rich-reply markup stays valid (regression guard).
+   */
+  it('preserves reply thread with space-only reply text (empty caption placeholder)', () => {
+    const r = buildRichReplyMatrixContent(
+      '@alice:example.org',
+      'original',
+      ' ',
+    );
+    expect(r.body).toContain('> <@alice:example.org>');
+    expect(r.body).toContain('original');
+    expect(r.format).toBe('org.matrix.custom.html');
+    expect(r.formatted_body.length).toBeGreaterThan(0);
+    const split = splitRichReplyPlainBody(r.body);
+    expect(split.reply).toBe('');
+    expect(split.quoted).toContain('@alice:example.org');
+  });
 });

packages/core/src/matrix/__tests__/edit-room-message-media-caption.test.ts

@@ -0,0 +1,69 @@
+import { describe, expect, it, vi } from 'vitest';
+
+import { applyMediaEditCaptionAndReply } from '../edit-room-message-media-caption';
+import {
+  MATRIX_CUSTOM_HTML_FORMAT,
+  splitRichReplyPlainBody,
+} from '../rich-reply';
+
+/** Covers `editRoomMessage` media branch in matrix-provider (empty caption + reply). */
+describe('applyMediaEditCaptionAndReply', () => {
+  it('preserves m.in_reply_to when caption is cleared but replyToId is set', async () => {
+    const combined = {
+      msgtype: 'm.image',
+      body: 'photo.png',
+      filename: 'photo.png',
+      url: 'mxc://hs/a',
+    };
+    const resolveReply = vi.fn().mockResolvedValue({
+      eventId: '$parent:example.org',
+      sender: '@alice:example.org',
+      body: 'original',
+    });
+
+    const out = await applyMediaEditCaptionAndReply(
+      combined,
+      '',
+      '$reply:event',
+      resolveReply,
+      'photo.png',
+    );
+
+    expect(resolveReply).toHaveBeenCalledWith('$reply:event');
+    expect(out['m.relates_to']).toEqual({
+      'm.in_reply_to': { event_id: '$parent:example.org' },
+    });
+    expect(out.format).toBe(MATRIX_CUSTOM_HTML_FORMAT);
+    expect(typeof out.formatted_body).toBe('string');
+    expect(out.formatted_body!.length).toBeGreaterThan(0);
+    expect(out.body).toContain('> <@alice:example.org>');
+    expect(out.body).toContain('original');
+    /** Same path as matrix-provider: `buildRichReplyMatrixContent(..., ' ')`. */
+    const split = splitRichReplyPlainBody(out.body);
+    expect(split.reply).toBe('');
+    expect(split.quoted).toContain('@alice:example.org');
+    expect(split.quoted).toContain('original');
+  });
+
+  it('uses filename fallback when caption and reply are absent', async () => {
+    const combined = {
+      msgtype: 'm.image',
+      body: 'x',
+      filename: 'x',
+      url: 'mxc://hs/b',
+    };
+    const resolveReply = vi.fn();
+
+    const out = await applyMediaEditCaptionAndReply(
+      combined,
+      '',
+      undefined,
+      resolveReply,
+      'fallback.png',
+    );
+
+    expect(resolveReply).not.toHaveBeenCalled();
+    expect(out.body).toBe('fallback.png');
+    expect(out['m.relates_to']).toBeUndefined();
+  });
+});

packages/core/src/matrix/client/hooks/use-user-privy-id-by-matrix-id.ts

@@ -6,7 +6,8 @@ import useSWR from 'swr';
 import { getLinkByMatrixUserIdAction } from '../../server/actions';
 
 export interface UseUserPrivyIdByMatrixIdInput {
-  matrixUserId: string;
+  /** When omitted or empty, no request is made (safe for conditional resolution). */
+  matrixUserId?: string;
 }
 
 export const useUserPrivyIdByMatrixId = ({
@@ -19,7 +20,11 @@ export const useUserPrivyIdByMatrixId = ({
     if (typeof window === 'undefined') return undefined;
     return determineEnvironment(window.location.href);
   }, []);
-  const arg = isLoadingJwt ? null : { matrixUserId, environment };
+  const trimmedId = matrixUserId?.trim();
+  const arg =
+    isLoadingJwt || !trimmedId
+      ? null
+      : { matrixUserId: trimmedId, environment };
 
   const { data: privyUserId, isLoading } = useSWR(
     [jwt ? arg : null, 'getLinkByMatrixUserId'],