fix: choose the reply From by an address the original names only in Bcc #87

src/lib/__tests__/reply-compose.test.ts

@@ -1,6 +1,7 @@
 import { describe, it, expect } from 'vitest';
-import type { Email } from '../../api/types';
+import type { Email, Identity } from '../../api/types';
 import { replyComposeParams } from '../reply-compose';
+import { resolveReplyIdentity } from '../reply-identity';
 
 const source = {
   id: 'm1',
@@ -26,6 +27,24 @@ describe('replyComposeParams', () => {
     expect(replyComposeParams('reply', source)?.prefillBody).toBeUndefined();
     expect(replyComposeParams('reply', source, undefined, '   ')?.prefillBody).toBeUndefined();
   });
+
+  it('lets the reply From match an address the message names only in Bcc (native #87)', () => {
+    const viaBcc = {
+      ...source,
+      to: [{ name: 'owner/repo', email: 'repo@noreply.github.com' }],
+      bcc: [{ email: 'github@example.com' }],
+    } as Email;
+    const params = replyComposeParams('reply', viaBcc);
+    expect(params?.replyTo?.bcc).toEqual([{ email: 'github@example.com' }]);
+    const identities = [
+      { id: 'main', name: 'Me', email: 'me@example.com', mayDelete: false },
+    ] as Identity[];
+    const resolved = resolveReplyIdentity(identities, params!.replyTo!, {
+      ownEmails: ['me@example.com'], catchAll: true, matchMode: 'domain',
+    });
+    expect(resolved?.identityId).toBe('main');
+    expect(resolved?.overrideEmail).toBe('github@example.com');
+  });
 });
 
 describe('replyComposeParams: quoted inline images', () => {

src/lib/reply-compose.ts

@@ -49,6 +49,10 @@ export function replyComposeParams(
       from: from ?? { email: '' },
       to: source.to,
       cc: source.cc,
+      // Never a recipient of the reply, but the composer picks the identity
+      // (and the catch-all From) by the address the message was delivered
+      // to, and a Sieve rule or a list may name that one only in Bcc.
+      bcc: source.bcc,
       // RFC 5322: a reply goes to Reply-To when the sender set one.
       replyToAddresses: source.replyTo,
       subject: source.subject ?? '',