Brushes: Yes in Delete Brush asks again when a stroke started using a brush meanwhile

The question for unused brushes checks again when Yes is chosen. If a stroke uses one of the brushes by then, the dialog asks with Remove Strokes and Cancel instead of deleting.

crates/ui-egui/src/dialogs/brush_delete.rs

@@ -28,6 +28,21 @@ pub fn ask(app: &mut VectorcraftApp, params: Value, used: bool) {
     app.ui.dialog = Some(Dialog::new(KIND, json!({"params": params, "used": used, "message": message})));
 }
 
+/// Whether a stroke uses one of `names` (`brush.unused`), or `None` when the query fails.
+pub fn used(app: &mut VectorcraftApp, names: &[String]) -> Option<bool> {
+    let unused = app.run("brush.unused", json!({})).ok()?;
+    let unused = unused.get("names").and_then(Value::as_array).cloned().unwrap_or_default();
+    Some(names.iter().any(|name| !unused.iter().any(|n| n.as_str() == Some(name))))
+}
+
+/// The brush names in `brush.delete` params (`name` or `names`).
+fn names(params: &Value) -> Vec<String> {
+    match params.get("name").and_then(Value::as_str) {
+        Some(name) => vec![name.to_string()],
+        None => params.get("names").and_then(Value::as_array).into_iter().flatten().filter_map(Value::as_str).map(str::to_string).collect(),
+    }
+}
+
 fn body(_: &mut VectorcraftApp, ui: &mut egui::Ui, d: &mut Dialog) -> DialogAction {
     let mut action = DialogAction::None;
     ui.horizontal(|ui| {
@@ -50,9 +65,14 @@ fn body(_: &mut VectorcraftApp, ui: &mut egui::Ui, d: &mut Dialog) -> DialogActi
     action
 }
 
-/// Closes before running, so a dialog the command opens stays open.
+/// Closes before running, so a dialog the command opens stays open. Yes on brushes that a stroke
+/// has started to use since the question opened asks again with Remove Strokes and Cancel.
 fn confirm(app: &mut VectorcraftApp, d: &Dialog) -> Result<Value, String> {
     let params = d.fields.get("params").cloned().unwrap_or_else(|| json!({}));
+    if !d.bool("used") && used(app, &names(&params)) == Some(true) {
+        ask(app, params, true);
+        return Ok(json!({}));
+    }
     app.ui.dialog = None;
     app.run("brush.delete", params)
 }

crates/ui-egui/src/dialogs/brush_delete/tests.rs

@@ -50,6 +50,25 @@ fn visible_yes_and_no_buttons_control_unused_deletion() {
     assert_eq!(app.session.active().unwrap().history.undo.len(), before + 1);
 }
 
+#[test]
+fn yes_asks_again_when_a_stroke_started_using_the_brush() {
+    let mut app = VectorcraftApp::new(Session::new(), Default::default());
+    app.run("file.new", json!({"width": 200, "height": 100})).unwrap();
+    let name = "10 pt. Oval";
+    let ctx = context();
+    ask(&mut app, json!({"names": [name]}), false);
+    let path = NodeId(app.run("shape.rectangle", json!({"x": 10, "y": 10, "width": 60, "height": 40})).unwrap()["id"].as_u64().unwrap());
+    app.run("brush.apply", json!({"name": name})).unwrap();
+    let before = app.session.active().unwrap().history.undo.len();
+    press(&ctx, &mut app, "Yes", 0.0);
+    assert!(app.ui.dialog.as_ref().is_some_and(|d| d.kind == KIND && d.bool("used")), "asks again with Remove Strokes");
+    assert_eq!(app.session.active().unwrap().history.undo.len(), before);
+    let stroke = app.session.active().unwrap().doc.node(path).and_then(|n| n.appearance.stroke()).unwrap();
+    assert_eq!(stroke.brush.as_deref(), Some(name));
+    press(&ctx, &mut app, "Remove Strokes", 1.0);
+    assert!(app.run("brush.get", json!({"name": name})).is_err());
+}
+
 #[test]
 fn visible_remove_strokes_and_cancel_buttons_control_used_deletion() {
     for choice in ["Cancel", "Remove Strokes"] {

crates/ui-egui/src/panels/brushes.rs

@@ -207,11 +207,9 @@ fn run_on(app: &mut VectorcraftApp, id: &str, names: &[String]) {
 /// Delete `names` after asking: Yes or No when none of them is in use, else Remove Strokes or
 /// Cancel. With `now` (Alt-click on the bottom button), brushes that are not in use go at once.
 fn delete(app: &mut VectorcraftApp, names: &[String], now: bool) {
-    let Ok(unused) = app.run("brush.unused", json!({})) else {
+    let Some(used) = crate::dialogs::brush_delete::used(app, names) else {
         return;
     };
-    let unused = unused.get("names").and_then(Value::as_array).cloned().unwrap_or_default();
-    let used = names.iter().any(|name| !unused.iter().any(|n| n.as_str() == Some(name)));
     if now && !used {
         run_on(app, "brush.delete", names);
         return;