Variables dialog: malformed entries can't crash an edit (#875)

`ui.dialog.set` can store any JSON in the dialog's `__variables` field, and the Define and Data
Sets pages write fields into its entries (`d["name"] = …`, `set["name"] = …`), which panics when an
entry is a number or a string. The dialog now normalizes the state each frame, keeping only object
entries in `defs`, `dataSets` and each set's `values`.

crates/ui-egui/src/variables_ui.rs

@@ -110,7 +110,7 @@ const METHODS: &[(&str, &str)] = &[("fit", "Fit"), ("fill", "Fill"), ("conform",
 pub fn body(app: &mut PhotocraftApp, ui: &mut egui::Ui, fields: &mut Map<String, Value>) {
     let t = Tokens::get(ui.ctx());
     let layers = layer_options(app);
-    let mut state = fields.get("__variables").cloned().unwrap_or_else(|| json!({"defs": [], "dataSets": []}));
+    let mut state = normalize(fields.get("__variables").unwrap_or(&Value::Null));
     let mut page = fields.get("__page").and_then(Value::as_str).unwrap_or("define").to_string();
 
     ui.set_min_width(420.0);
@@ -137,6 +137,22 @@ pub fn body(app: &mut PhotocraftApp, ui: &mut egui::Ui, fields: &mut Map<String,
     fields.insert("__page".into(), json!(page));
 }
 
+/// The dialog state with only object entries in `defs`, `dataSets` and each set's `values`.
+/// `ui.dialog.set` can store any JSON in `__variables`, and the pages write fields into entries
+/// (`d["name"] = …`), which panics on a number or a string.
+fn normalize(state: &Value) -> Value {
+    let objects =
+        |v: Option<&Value>| -> Vec<Value> { v.and_then(Value::as_array).map(|a| a.iter().filter(|e| e.is_object()).cloned().collect()).unwrap_or_default() };
+    let sets: Vec<Value> = objects(state.get("dataSets"))
+        .into_iter()
+        .map(|mut set| {
+            set["values"] = Value::Array(objects(set.get("values")));
+            set
+        })
+        .collect();
+    json!({"defs": objects(state.get("defs")), "dataSets": sets})
+}
+
 fn define_page(ui: &mut egui::Ui, _t: &Tokens, layers: &[(u64, String, bool)], state: &mut Value) {
     let Some(defs) = state.get_mut("defs").and_then(Value::as_array_mut) else { return };
     ui.label(tl!("Variables bind a layer's visibility, text or pixels to a named data slot."));
@@ -339,6 +355,15 @@ mod tests {
         assert_eq!(data_set_index(&fields, 0), 0);
     }
 
+    #[test]
+    fn normalize_keeps_only_object_entries() {
+        let s = normalize(&json!({"defs": [1, {"name": "a"}], "dataSets": ["x", {"name": "A", "values": [true, {"variable": "a"}]}, {"values": 3}]}));
+        assert_eq!(s, json!({"defs": [{"name": "a"}], "dataSets": [{"name": "A", "values": [{"variable": "a"}]}, {"values": []}]}));
+        for bad in [Value::Null, json!(5), json!("s"), json!([1]), json!({"defs": "x", "dataSets": {}})] {
+            assert_eq!(normalize(&bad), json!({"defs": [], "dataSets": []}), "{bad}");
+        }
+    }
+
     #[test]
     fn owns_detects_the_field() {
         let mut f = Map::new();

crates/ui-egui/tests/variables_data_sets.rs

@@ -55,3 +55,37 @@ fn out_of_range_data_set_index_is_clamped_before_delete() {
     h.get_by_label("Delete").click();
     h.run_steps(2);
 }
+
+/// `ui.dialog.set` can store any JSON in `__variables`; the editors write into its entries.
+fn app_with_malformed_variables(page: &str) -> PhotocraftApp {
+    let mut app = PhotocraftApp::new(photocraft_engine::Session::new(), photocraft_ui_egui::Services::default());
+    app.run("file.new", json!({"width": 64, "height": 64})).unwrap();
+    app.run("layer.new.layer", json!({})).unwrap();
+    let mut fields = Map::new();
+    fields.insert(
+        "__variables".into(),
+        json!({"defs": [42, {"name": "v1", "layer": 0, "type": "textReplacement"}], "dataSets": ["bad", {"name": "A", "values": [7, "x"]}, {"name": "B", "values": "nope"}]}),
+    );
+    fields.insert("__page".into(), json!(page));
+    app.ui.open_dialog(DialogKind::Command, fields);
+    app
+}
+
+fn type_into_first_text_field(h: &mut Harness<'static, PhotocraftApp>) {
+    h.query_all_by_role(egui::accesskit::Role::TextInput).next().expect("a text field").click();
+    h.run_steps(2);
+    h.query_all_by_role(egui::accesskit::Role::TextInput).next().expect("a text field").type_text("z");
+    h.run_steps(2);
+}
+
+#[test]
+fn malformed_variable_entries_are_dropped_before_an_edit() {
+    for page in ["define", "dataSets"] {
+        let mut h = harness(app_with_malformed_variables(page));
+        type_into_first_text_field(&mut h);
+        let state = &h.state().ui.dialogs.last().unwrap().fields["__variables"];
+        assert_eq!(state["defs"].as_array().unwrap().len(), 1, "{page}: {state}");
+        assert_eq!(state["dataSets"].as_array().unwrap().len(), 2, "{page}: {state}");
+        assert!(state["dataSets"].as_array().unwrap().iter().all(|s| s["values"].as_array().unwrap().iter().all(|v| v.is_object())), "{page}: {state}");
+    }
+}