Effect Controls: a lock request with no layer shown is an error (#3193)

With the lock kept for a layer of another comp and nothing selected in
the active one, ui.set {effectControlsLocked: true} reported success.
It now returns the documented error and leaves the kept lock alone.

crates/ui-egui/src/control.rs

@@ -281,11 +281,15 @@ fn set_ui(app: &mut EffectcraftApp, ctx: &egui::Context, p: &Value) -> Outcome {
     {
         return err(e);
     }
-    // Effect Controls' tab lock: on locks it to the layer it shows.
-    if let Some(on) = p.get("effectControlsLocked").and_then(Value::as_bool)
-        && crate::panels::effect_controls::set_lock(app, on) != on
-    {
-        return err("effectControlsLocked: Effect Controls shows no layer to lock");
+    // Effect Controls' tab lock: on locks it to the layer it shows. With no layer shown (the
+    // lock kept for a layer of another comp, nothing selected here) a lock request is an error
+    // and the kept lock stays.
+    if let Some(on) = p.get("effectControlsLocked").and_then(Value::as_bool) {
+        crate::panels::effect_controls::scope_lock(app);
+        let shown = crate::panels::effect_controls::shown_layer_id(app).is_some();
+        if (on && !shown) || crate::panels::effect_controls::set_lock(app, on) != on {
+            return err("effectControlsLocked: Effect Controls shows no layer to lock");
+        }
     }
     set_ui_layout(app, p)
 }

crates/ui-egui/tests/it/ui_effect_controls.rs

@@ -1013,6 +1013,36 @@ fn replacing_the_project_unlocks_effect_controls() {
     assert_eq!(h.state().ui.effect_controls_lock, None, "the lock belongs to the replaced project");
 }
 
+/// #3193: with the lock kept for a layer of another comp and no layer selected in the active one,
+/// Effect Controls shows no layer: a lock request is an error and the kept lock stays.
+#[test]
+fn a_lock_request_with_no_layer_shown_fails_and_keeps_the_other_comps_lock() {
+    use effectcraft_ui_egui::control::{self, ControlRequest, Outcome};
+    fn send(h: &mut Harness<'_, EffectcraftApp>) -> serde_json::Value {
+        let ctx = h.ctx.clone();
+        let (req, _rx) = ControlRequest::new("ui.set", json!({"effectControlsLocked": true}));
+        let now = h.state().now();
+        match control::handle(h.state_mut(), &ctx, &req, now) {
+            Outcome::Done(v) => v,
+            _ => panic!("ui.set: no immediate reply"),
+        }
+    }
+    let (app, a, _, _, _) = two_layers();
+    let mut h = Harness::builder().with_size(egui::vec2(1600.0, 1000.0)).build_eframe(|_| app);
+    h.run_steps(4);
+    assert_eq!(send(&mut h)["ok"], true);
+    let kept = h.state().ui.effect_controls_lock;
+    assert_eq!(kept.map(|l| l.layer), Some(a));
+    // Another comp becomes active, nothing selected in it.
+    h.state_mut().session.execute("comp.new", json!({"name": "Other", "width": 320, "height": 180, "frameRate": 30, "duration": 5})).unwrap();
+    h.state_mut().session.state.selected_layers.clear();
+    h.run_steps(3);
+    assert_ne!(h.state().session.active_comp_id().map(|c| c.0), kept.map(|l| l.comp), "another comp is active");
+    let reply = send(&mut h);
+    assert_eq!(reply["ok"], false, "{reply}");
+    assert_eq!(h.state().ui.effect_controls_lock, kept, "the other comp's lock stays");
+}
+
 /// #3193: a lock request right after the project is replaced, before the next frame, is not
 /// answered with the old project's lock: the reply matches the lock the panel keeps.
 #[test]