feat: heuristic session titles and grouped sub-task tree

changelog.d/session-tree-ui.added.md

@@ -0,0 +1 @@
+Session titles now describe their first task, and the session picker groups sub-tasks under their parent session.

n00n-lua/src/api/session.rs

@@ -38,7 +38,8 @@ async fn roundtrip(
 /// Lists sessions stored for the current project. Answered from a
 /// background scan, so a slow disk never blocks the UI.
 ///
-/// @return (table|nil, string|nil) Array of `{id, title, updated_at}`, or nil and an error.
+/// @return (table|nil, string|nil) Array of `{id, title, display_title, kind,
+/// parent_id, updated_at, cwd, model}`, or nil and an error.
 /// @example
 /// local stored, err = n00n.session.list()
 #[lua_fn]
@@ -114,7 +115,8 @@ async fn delete(
 /// Starts a new session in the current project.
 ///
 /// @param opts table? Optional fields: prompt (string) first user message
-///   to submit right away; focus (boolean) switch the UI to the new session.
+///   to submit right away; focus (boolean) switch the UI to the new session;
+///   parent_id (string?) session that spawned this session.
 /// @return (string|nil, string|nil) New session id, or nil and an error.
 /// @example
 /// local id, err = n00n.session.new({ prompt = "fix the tests", focus = true })
@@ -124,14 +126,24 @@ async fn new(
     #[ctx] tx: Option<flume::Sender<UiAction>>,
     opts: Option<Table>,
 ) -> LuaResult<Pair> {
-    let (prompt, focus) = match opts {
+    let (prompt, focus, parent_id) = match opts {
         Some(opts) => (
             opts.get("prompt")?,
             opts.get("focus").unwrap_or_else(|_| false),
+            opts.get("parent_id")?,
         ),
-        None => (None, false),
+        None => (None, false, None),
     };
-    roundtrip(lua, tx, SessionRequest::New { prompt, focus }).await
+    roundtrip(
+        lua,
+        tx,
+        SessionRequest::New {
+            prompt,
+            focus,
+            parent_id,
+        },
+    )
+    .await
 }
 
 /// Sends {text} as a regular user prompt to a live session. The text is

n00n-lua/src/api/util/command.rs

@@ -406,14 +406,32 @@ pub enum WinCommand {
 pub enum SessionRequest {
     List,
     Live,
-    Status { id: String },
+    Status {
+        id: String,
+    },
     Current,
-    New { prompt: Option<String>, focus: bool },
-    Prompt { id: Option<String>, text: String },
-    Cancel { id: String },
-    Focus { id: String },
-    Delete { id: String },
-    SetTitle { id: String, title: String },
+    New {
+        prompt: Option<String>,
+        focus: bool,
+        parent_id: Option<String>,
+    },
+    Prompt {
+        id: Option<String>,
+        text: String,
+    },
+    Cancel {
+        id: String,
+    },
+    Focus {
+        id: String,
+    },
+    Delete {
+        id: String,
+    },
+    SetTitle {
+        id: String,
+        title: String,
+    },
 }
 
 pub type SessionReply = Result<serde_json::Value, String>;

n00n-lua/tests/plugin_host.rs

@@ -2632,6 +2632,103 @@ fn sessions_plugin_registers_commands() {
     assert!(names.contains(&"/rename"), "missing /rename in {names:?}");
 }
 
+#[test]
+fn sessions_plugin_declares_render_before_callbacks() {
+    let source = include_str!("../../plugins/sessions/init.lua");
+    let render_decl = source
+        .find("\nlocal render\n")
+        .expect("sessions plugin must forward-declare local render");
+    let set_sel = source
+        .find("local function set_sel")
+        .expect("sessions plugin must define set_sel");
+    assert!(
+        render_decl < set_sel,
+        "local render must precede set_sel so navigation callbacks capture it as an upvalue, not a nil global"
+    );
+}
+
+#[test]
+fn sessions_plugin_rename_persists_kind_prefix_in_stored_title() {
+    let source = include_str!("../../plugins/sessions/init.lua");
+    let commit = source
+        .find("local function commit_rename()")
+        .expect("commit_rename");
+    let body = &source[commit..];
+    let stored_assign = body
+        .find("board.stored[si].title")
+        .expect("commit_rename updates board.stored title");
+    let snippet = &body[stored_assign..stored_assign + 80];
+    assert!(
+        snippet.contains("stored_title"),
+        "in-memory stored title must keep the kind prefix via stored_title, got: {snippet}"
+    );
+}
+
+#[test]
+fn sessions_picker_groups_more_than_twenty_children() {
+    let registry = fresh_registry();
+    let host = PluginHost::new(Arc::clone(&registry)).unwrap();
+    let mut source = include_str!("../../plugins/sessions/init.lua").to_string();
+    source.push_str(
+        r#"
+n00n.api.register_tool({
+  name = "sessions_group_probe",
+  description = "test",
+  schema = { type = "object", properties = {} },
+  audiences = { "main" },
+  handler = function()
+    local parent = { id = "parent", children = {} }
+    local all_nodes = { parent }
+    local rank = { parent = 0 }
+    for i = 1, 21 do
+      local child = { id = "child-" .. i, parent_id = parent.id, updated_at = 100 - i, children = {} }
+      rank[child.id] = i
+      parent.children[i] = child
+      all_nodes[#all_nodes + 1] = child
+    end
+    local expanded_state = { ["group:parent:1"] = true }
+     group_node(parent, all_nodes, rank, expanded_state)
+     local first_child = parent.children[1].children[1]
+     local original_parent = first_child.parent_id
+     local group_id = first_child.group_id
+     group_node(parent, all_nodes, rank, expanded_state)
+     return n00n.json.encode({
+      buckets = #parent.children,
+      first_id = parent.children[1].id,
+      first_expanded = parent.children[1].expanded,
+      first_children = #parent.children[1].children,
+       second_children = #parent.children[2].children,
+       child_parent = original_parent,
+       child_group = group_id,
+       child_parent_after_refresh = parent.children[1].children[1].parent_id,
+       child_group_after_refresh = parent.children[1].children[1].group_id,
+
+    })
+  end,
+})
+"#,
+    );
+    host.load_source("sessions_group_test", &source).unwrap();
+
+    let output = exec_tool(&registry, "sessions_group_probe", serde_json::json!({})).unwrap();
+    let grouped: serde_json::Value = serde_json::from_str(&output).unwrap();
+    assert_eq!(grouped["buckets"], serde_json::json!(2));
+    assert_eq!(grouped["first_id"], serde_json::json!("group:parent:1"));
+    assert_eq!(grouped["first_expanded"], serde_json::json!(true));
+    assert_eq!(grouped["first_children"], serde_json::json!(20));
+    assert_eq!(grouped["second_children"], serde_json::json!(1));
+    assert_eq!(grouped["child_parent"], serde_json::json!("parent"));
+    assert_eq!(grouped["child_group"], serde_json::json!("group:parent:1"));
+    assert_eq!(
+        grouped["child_parent_after_refresh"],
+        serde_json::json!("parent")
+    );
+    assert_eq!(
+        grouped["child_group_after_refresh"],
+        serde_json::json!("group:parent:1")
+    );
+}
+
 #[test]
 fn job_callback_finishes_after_handler_returns_nil() {
     let reg = fresh_registry();