Desk door: failing socket test, a read of an oversize fork is fork_too_large naming the fork

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

crates/huginn-daemon/tests/desk_door.rs

@@ -783,3 +783,46 @@ fn the_newest_fork_too_large_is_named_and_its_cursor_resumes_to_the_older_forks(
     let rest = page_ids(ask(&desk, "m-p", &forks_page("x", Some("c2"))));
     assert_eq!(rest, (vec!["eureka-state:question:Q2".to_string(), FORK.to_string()], None));
 }
+
+/// Grows `fork` over the socket until a READ of it no longer fits the reply cap; returns the raw reply.
+fn grown_until_read_overflows(desk: &Path, hash: &str, fork: &str) -> CultNetMessage {
+    let note = "a long reason, ".repeat(60);
+    for sent in 1..400_u32 {
+        let reply = exchange(desk, &desk_bytes("m-read", &fork_read("x", fork))).expect("the door replied");
+        if !matches!(decode_desk_response(&reply).unwrap().1, Ok(DeskResponse::Fork { .. })) {
+            return reply;
+        }
+        let mut grow = answer("x", hash, &format!("00000000-0000-4000-8000-{sent:012}"));
+        if let DeskRequest::Answer { request, .. } = &mut grow {
+            request.fork_id = fork.into();
+            request.answer = Some(ForkAnswer { choice: None, note: Some(note.clone()) });
+        }
+        assert!(matches!(ask(desk, "m-w", &grow), DeskResponse::Answered { .. }));
+    }
+    panic!("the record does not grow")
+}
+
+/// A READ of a fork whose entry is past the reply cap is `fork_too_large` naming the fork, with no
+/// order and no cursor; a fitting fork still reads; the list's refusal is unchanged; the generic
+/// response-too-large stays for every other reply.
+#[test]
+fn a_read_of_an_oversize_fork_is_fork_too_large_naming_only_the_fork() {
+    let _serial = serial();
+    let (_root, _run, hash, desk, _daemon) = three_forks();
+    let big = "eureka-state:question:Q2";
+    let reply = grown_until_read_overflows(&desk, &hash, big);
+    let (id, response) = decode_desk_response(&reply).unwrap();
+    assert_eq!(id, "m-read");
+    let (code, text) = refusal_of(&response.unwrap()).expect("a not-stored refusal");
+    assert_eq!(code, "fork_too_large");
+    assert!(text.contains(big) && !text.contains("order") && !text.contains("cursor") && !text.contains(" c1"), "{text}");
+    // Fitting forks read, the others untouched.
+    for fork in [FORK, "eureka-state:question:Q3"] {
+        assert!(matches!(ask(&desk, "m-ok", &fork_read("x", fork)), DeskResponse::Fork { .. }));
+    }
+    // The list still names the fork and its order, and the cursor goes on.
+    let listed = ask(&desk, "m-l", &forks_page("x", Some("c2")));
+    let (code, text) = refusal_of(&listed).unwrap();
+    assert_eq!(code, "fork_too_large");
+    assert!(text.contains(big) && text.contains("order 1") && text.contains("c1"), "{text}");
+}