Report changed=false when list indentation is capped

Fixes #425

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

crates/engine/src/textedit.rs

@@ -146,9 +146,15 @@ fn list_key(s: &mut Session, key: &str, shift: bool) -> Result<bool> {
 }
 
 /// Cmd/Ctrl+] and Cmd/Ctrl+[ while editing: the selected list items a level deeper or out, like
-/// Tab and Shift+Tab. Returns whether anything changed (text that isn't a list stays as it is).
+/// Tab and Shift+Tab. Returns whether anything changed (text that isn't a list and items already
+/// at the deepest level stay as they are).
 pub fn list_indent(s: &mut Session, out: bool) -> Result<bool> {
-    list_key(s, "Tab", out)
+    let Some(id) = s.ds()?.text_edit.as_ref().map(|te| te.id) else { return Ok(false) };
+    let before = text_of(s, id)?;
+    if !list_key(s, "Tab", out)? {
+        return Ok(false);
+    }
+    Ok(text_of(s, id)? != before)
 }
 
 /// The kind of word char `i` belongs to: 0 for spaces and punctuation, else its script, so a word

crates/engine/tests/list_indent_response.rs

@@ -0,0 +1,71 @@
+//! `text.listIndent` / `text.listOutdent` report `changed` only when the document changed.
+#![allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
+
+use figcraft_engine::{
+    Session,
+    doc::{ListStyle, NodeId, NodeKind},
+};
+use serde_json::json;
+
+fn editing_list(indent: u8) -> (Session, NodeId) {
+    let mut s = Session::new();
+    let value = s.execute("node.create", &json!({"type":"text", "props":{"characters":"a"}})).unwrap();
+    let id = NodeId(value["id"].as_u64().unwrap());
+    s.execute("text.listStyle", &json!({"ids":[id.0], "style":"bulleted"})).unwrap();
+    s.execute("node.set", &json!({"id":id.0, "props":{"indentation":indent}})).unwrap();
+    s.execute("text.edit.begin", &json!({"id":id.0, "caret":0})).unwrap();
+    (s, id)
+}
+
+fn list_state(s: &Session, id: NodeId) -> (ListStyle, u8) {
+    let NodeKind::Text(t) = &s.doc().unwrap().node(id).unwrap().kind else { panic!("not text") };
+    let p = t.para_list(0);
+    (p.list, p.indent)
+}
+
+#[test]
+fn indent_at_cap_reports_false() {
+    let (mut s, id) = editing_list(8);
+    let before = s.doc().unwrap().clone();
+    let result = s.execute("text.listIndent", &json!({})).unwrap();
+    assert_eq!(list_state(&s, id), (ListStyle::Bulleted, 8));
+    assert_eq!(before, *s.doc().unwrap());
+    assert_eq!(result["changed"], json!(false));
+}
+
+#[test]
+fn indent_from_zero_reports_true() {
+    let (mut s, id) = editing_list(0);
+    let result = s.execute("text.listIndent", &json!({})).unwrap();
+    assert_eq!(list_state(&s, id), (ListStyle::Bulleted, 1));
+    assert_eq!(result["changed"], json!(true));
+}
+
+#[test]
+fn outdent_from_zero_reports_true() {
+    let (mut s, id) = editing_list(0);
+    let result = s.execute("text.listOutdent", &json!({})).unwrap();
+    assert_eq!(list_state(&s, id).0, ListStyle::None);
+    assert_eq!(result["changed"], json!(true));
+}
+
+#[test]
+fn indent_plain_text_reports_false() {
+    let mut s = Session::new();
+    let value = s.execute("node.create", &json!({"type":"text", "props":{"characters":"a"}})).unwrap();
+    let id = NodeId(value["id"].as_u64().unwrap());
+    s.execute("text.edit.begin", &json!({"id":id.0, "caret":0})).unwrap();
+    let before = s.doc().unwrap().clone();
+    let result = s.execute("text.listIndent", &json!({})).unwrap();
+    assert_eq!(before, *s.doc().unwrap());
+    assert_eq!(result["changed"], json!(false));
+}
+
+#[test]
+fn tab_keys_still_nest_and_unnest() {
+    let (mut s, id) = editing_list(0);
+    s.execute("text.edit.key", &json!({"key":"Tab"})).unwrap();
+    assert_eq!(list_state(&s, id), (ListStyle::Bulleted, 1));
+    s.execute("text.edit.key", &json!({"key":"Tab", "shift":true})).unwrap();
+    assert_eq!(list_state(&s, id), (ListStyle::Bulleted, 0));
+}