Don't record an undo step for an abandoned empty text box

Fixes #423

Co-Authored-By: Claude Haiku 5.5 <[email protected]>
Co-Authored-By: Claude Sonnet 5.5 <[email protected]>

crates/engine/src/textedit.rs

@@ -38,16 +38,17 @@ pub fn end(s: &mut Session) -> Result<()> {
         let _ = doc.remove(te.id);
         s.ds_mut()?.selection.clear();
     }
-    s.commit_interaction()?;
     if empty && te.created {
-        // Nothing to undo for a text box that was never filled.
+        // Nothing to undo for a text box that was never filled. The gesture snapshot was taken
+        // after the layer was added, so it still holds it: re-base it on the document without the
+        // layer, and committing then records no step (and leaves the redo stack alone).
         let ds = s.ds_mut()?;
-        if let Some(last) = ds.history.undo.last()
-            && *last.doc == *ds.doc
-        {
-            ds.history.undo.pop();
+        let doc = ds.doc.clone();
+        if let Some(it) = ds.interaction.as_mut() {
+            it.doc = doc;
         }
     }
+    s.commit_interaction()?;
     let ds = s.ds_mut()?;
     ds.revision += 1;
     Ok(())

crates/engine/tests/empty_text_box_undo.rs

@@ -0,0 +1,60 @@
+#![allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
+
+use figcraft_engine::{
+    Session,
+    doc::NodeKind,
+    tools::{PointerEvent, PointerKind},
+};
+use serde_json::json;
+
+fn text_count(s: &Session) -> usize {
+    let doc = s.doc().unwrap();
+    doc.node(s.page().unwrap()).unwrap().children.iter().filter(|id| matches!(doc.node(**id).unwrap().kind, NodeKind::Text(_))).count()
+}
+
+fn rect_count(s: &Session) -> usize {
+    let doc = s.doc().unwrap();
+    doc.node(s.page().unwrap()).unwrap().children.len() - text_count(s)
+}
+
+fn click_and_abandon(s: &mut Session) {
+    s.execute("tool.text", &json!({})).unwrap();
+    s.pointer(&PointerEvent::at(PointerKind::Down, 300.0, 300.0, 1.0)).unwrap();
+    s.pointer(&PointerEvent::at(PointerKind::Up, 300.0, 300.0, 1.0)).unwrap();
+    assert_eq!(text_count(s), 1);
+    s.execute("text.edit.end", &json!({})).unwrap();
+    assert_eq!(text_count(s), 0);
+}
+
+#[test]
+fn abandoning_empty_text_does_not_create_an_undo_step() {
+    let mut s = Session::new();
+    assert_eq!(s.undo_depth(), (0, 0));
+    click_and_abandon(&mut s);
+    assert_eq!(s.undo_depth(), (0, 0));
+    s.execute("edit.undo", &json!({})).unwrap();
+    assert_eq!(text_count(&s), 0, "Undo restored the abandoned empty layer");
+}
+
+#[test]
+fn abandoning_empty_text_keeps_the_previous_undo_step_first() {
+    let mut s = Session::new();
+    s.execute("shape.rectangle", &json!({"x": 0, "y": 0, "width": 10, "height": 10})).unwrap();
+    click_and_abandon(&mut s);
+    assert_eq!(s.undo_labels(2), vec!["Rectangle".to_string()]);
+    s.execute("edit.undo", &json!({})).unwrap();
+    assert_eq!(text_count(&s), 0);
+    assert_eq!(rect_count(&s), 0, "the first Undo must remove the rectangle");
+}
+
+#[test]
+fn abandoning_empty_text_keeps_the_redo_stack() {
+    let mut s = Session::new();
+    s.execute("shape.rectangle", &json!({"x": 0, "y": 0, "width": 10, "height": 10})).unwrap();
+    s.execute("edit.undo", &json!({})).unwrap();
+    assert_eq!(s.undo_depth(), (0, 1));
+    click_and_abandon(&mut s);
+    assert_eq!(s.undo_depth(), (0, 1), "the document is back where it was, so Redo still applies");
+    s.execute("edit.redo", &json!({})).unwrap();
+    assert_eq!(rect_count(&s), 1);
+}