Personas a remote post is addressed to see it, named or not

A remote post decided who here may see it by its Mention tags alone. A
followers-only post addressed in to or cc to a persona without naming
it (Akkoma's to[], or a GoToSocial edit that took the @name out while
the post stayed addressed to the persona) was hidden from that persona.
Such personas are now kept as silent mentions, as Mastodon does: they
see the post and it reaches their home, and no list shows them as
mentioned. An edit never narrows who a post was for.

The GoToSocial note that showed it is the first captured fixture
(Fixtures/gotosocial), and parses with its lone tag, to and cc.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

PrivaPub.Tests/Federation/InboxScenarioTests.cs

@@ -263,6 +263,28 @@ namespace PrivaPub.Tests.Federation
 			Assert.Equal(alice.Id, mention.AccountId);
 		}
 
+		// GoToSocial kept a persona in cc after an edit took the @name out, and Akkoma addresses with to[] alone: the persona it
+		// is addressed to sees a followers-only post as a silent mention, which no list shows as a mention (found by the town)
+		[Fact]
+		public async Task A_followers_only_post_addressed_to_a_persona_without_naming_it_is_a_silent_mention()
+		{
+			var token = TestContext.Current.CancellationToken;
+			var alice = await LocalAvatar("alice");
+			var bob = new RemoteActor(_peer, "bob");
+			var create = PublicCreate(bob, default, alice.Uri);
+			create["object"]!["to"] = bob.Id + "/followers";
+			create["object"]!["cc"] = alice.Uri;
+
+			await Deliver(bob, "/human-centipede", create);
+
+			var post = await DB.Default.Find<Post>().Match(p => p.ActorURI == bob.Id).ExecuteSingleAsync(token);
+			Assert.Equal(PostVisibility.FollowersOnly, post.Visibility);
+			var mention = Assert.Single(post.Mentions);
+			Assert.True(mention.Silent);
+			Assert.Equal(alice.Id, mention.AccountId);
+			Assert.True(await PrivaPub.Domain.Privacy.VisibilityPolicy.CanSee(post, alice.Id, token));
+		}
+
 		[Fact]
 		public async Task A_suspended_domain_is_dropped_before_its_key_is_fetched()
 		{

PrivaPub.Tests/Federation/NoteParserTests.cs

@@ -57,6 +57,19 @@ namespace PrivaPub.Tests.Federation
 			Assert.Null(note.Updated);
 		}
 
+		// GoToSocial writes a lone tag, and lone to and cc, as plain values instead of arrays (captured by the town)
+		[Fact]
+		public void Reads_a_gotosocial_reply_whose_only_tag_and_audience_are_single_values()
+		{
+			var note = NoteParser.Parse(JsonNode.Parse(File.ReadAllText(Path.Combine(AppContext.BaseDirectory, "Fixtures", "gotosocial",
+				"followers-only-reply-one-tag.json"))));
+
+			var mention = Assert.Single(note.Mentions);
+			Assert.Equal("https://privapub.test/peasants/flor_pp98", mention.ActorURI);
+			Assert.Equal(["https://gts.test/users/ines_gt59/followers"], note.To);
+			Assert.Equal(["https://privapub.test/peasants/flor_pp98"], note.Cc);
+		}
+
 		[Fact]
 		public void Reads_a_lemmy_page_with_a_title()
 		{

PrivaPub.Tests/Fixtures/gotosocial/followers-only-reply-one-tag.json

@@ -0,0 +1 @@
+{"attributedTo":"https://gts.test/users/ines_gt59","cc":"https://privapub.test/peasants/flor_pp98","content":"\u003Cp\u003E\u003Cspan class=\u0022h-card\u0022\u003E\u003Ca href=\u0022https://privapub.test/@flor_pp98\u0022 class=\u0022u-url mention\u0022 rel=\u0022nofollow noreferrer noopener\u0022 target=\u0022_blank\u0022\u003E@\u003Cspan\u003Eflor_pp98\u003C/span\u003E\u003C/a\u003E\u003C/span\u003E bicycle the window bicycle tomorrow festival (p111)\u003C/p\u003E","contentMap":{"en":"\u003Cp\u003E\u003Cspan class=\u0022h-card\u0022\u003E\u003Ca href=\u0022https://privapub.test/@flor_pp98\u0022 class=\u0022u-url mention\u0022 rel=\u0022nofollow noreferrer noopener\u0022 target=\u0022_blank\u0022\u003E@\u003Cspan\u003Eflor_pp98\u003C/span\u003E\u003C/a\u003E\u003C/span\u003E bicycle the window bicycle tomorrow festival (p111)\u003C/p\u003E"},"id":"https://gts.test/users/ines_gt59/statuses/01M44BKDVTWFAMAQ3YSBM4QETY","inReplyTo":"https://privapub.test/peasants/flor_pp98/scribbles/6ac2beaf092dc0af8ce6035e","interactionPolicy":{"canAnnounce":{"automaticApproval":["https://gts.test/users/ines_gt59"]},"canLike":{"automaticApproval":["https://gts.test/users/ines_gt59","https://gts.test/users/ines_gt59/followers","https://privapub.test/peasants/flor_pp98"]},"canQuote":{"automaticApproval":["https://gts.test/users/ines_gt59"]},"canReply":{"automaticApproval":["https://gts.test/users/ines_gt59","https://gts.test/users/ines_gt59/followers","https://privapub.test/peasants/flor_pp98"]}},"published":"2026-10-04T21:02:31Z","replies":{"first":{"id":"https://gts.test/users/ines_gt59/statuses/01M44BKDVTWFAMAQ3YSBM4QETY/replies?page=true","next":"https://gts.test/users/ines_gt59/statuses/01M44BKDVTWFAMAQ3YSBM4QETY/replies?page=true\u0026only_other_accounts=false","partOf":"https://gts.test/users/ines_gt59/statuses/01M44BKDVTWFAMAQ3YSBM4QETY/replies","type":"CollectionPage"},"id":"https://gts.test/users/ines_gt59/statuses/01M44BKDVTWFAMAQ3YSBM4QETY/replies","type":"Collection"},"tag":{"href":"https://privapub.test/peasants/flor_pp98","name":"@flor_pp98@privapub.test","type":"Mention"},"to":"https://gts.test/users/ines_gt59/followers","type":"Note","url":"https://gts.test/@ines_gt59/statuses/01M44BKDVTWFAMAQ3YSBM4QETY"}