Flip is refused on a SmartArt graphic instead of turning it into a plain group

PowerPoint greys Flip out for a SmartArt graphic (SmartArt Design ▸ Right to
Left is the way to mirror it), also inside a group, as ungrouping would hand
the flip to the graphic. Before, a flip turned it into a plain group that the
smartArt.* commands then refused. arrange.flipHorizontal and flipVertical
reach the check through shape.flip. Split out of the SmartArt PR at review.

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

crates/engine/src/cmd/shape/size.rs

@@ -191,6 +191,16 @@ pub(super) fn rotate(s: &mut Session, p: &Value) -> Result<Value> {
 pub(super) fn flip(s: &mut Session, p: &Value) -> Result<Value> {
     let v = str_param(p, "axis").unwrap_or("horizontal").starts_with('v');
     edit_geometry(s, p, "shape.flip", |sh| {
+        // PowerPoint greys Flip out for a SmartArt graphic (SmartArt Design > Right to Left mirrors it),
+        // also inside a group: ungrouping would hand the flip to the graphic.
+        let mut graphic = false;
+        deckcraft_model::walk(std::slice::from_ref(&*sh), &mut |x, _| graphic |= x.diagram.is_some());
+        if graphic {
+            return Err(bad(
+                "shape.flip",
+                "Flip is not available for a SmartArt graphic (it would turn it into a plain group); use `smartArt.layout` to change how it is laid out",
+            ));
+        }
         if let Some(x) = sh.xfrm.as_mut() {
             if v {
                 x.flip_v = !x.flip_v;

crates/engine/src/tests.rs

@@ -6509,3 +6509,27 @@ fn save_to_image_path_is_an_error_not_zip_bytes() {
     }
     let _ = std::fs::remove_dir_all(&dir);
 }
+
+#[test]
+fn flip_is_refused_on_a_smartart_graphic_and_leaves_it_a_graphic() {
+    let mut s = session();
+    s.execute("slide.new", &json!({"layout": "blank"})).unwrap();
+    s.execute("insert.textBox", &json!({"text": "Goals\nRevenue"})).unwrap();
+    let gid = s.execute("smartArt.fromText", &json!({"kind": "blockList"})).unwrap()["id"].as_u64().unwrap();
+    for cmd in ["arrange.flipHorizontal", "arrange.flipVertical", "shape.flip"] {
+        let e = s.execute(cmd, &json!({"ids": [gid]})).unwrap_err().to_string();
+        assert!(e.contains("SmartArt") && e.contains("smartArt.layout"), "{cmd}: {e}");
+    }
+    // Grouped with another shape it cannot be flipped either: ungrouping would hand it the flip.
+    let other = s.execute("insert.textBox", &json!({"text": "x"})).unwrap()["id"].as_u64().unwrap();
+    let group = s.execute("arrange.group", &json!({"ids": [gid, other]})).unwrap()["id"].as_u64().unwrap();
+    let e = s.execute("shape.flip", &json!({"ids": [group]})).unwrap_err().to_string();
+    assert!(e.contains("SmartArt"), "{e}");
+    s.execute("arrange.ungroup", &json!({"ids": [group]})).unwrap();
+    // Still a SmartArt graphic: smartArt commands keep working.
+    s.execute("smartArt.layout", &json!({"id": gid, "kind": "cycle"})).unwrap();
+    // Ordinary shapes still flip.
+    let b = s.execute("insert.textBox", &json!({"text": "x"})).unwrap();
+    let id = b["id"].as_u64().unwrap();
+    assert_eq!(s.execute("arrange.flipHorizontal", &json!({"ids": [id]})).unwrap(), json!(1));
+}