Variables: Import and Export Data Sets… show file dialogs on macOS and keep the window running

The Variables panel menu called import_datasets and export_datasets
directly, so their file dialogs were asked for outside an entry and
shown in line. macOS shows no dialog in line, so the two items did
nothing there. On Linux the dialog held the window until it closed.

Both items now go through picks::button, as the Libraries panel
menu's Import Library… and Export Library… do. When the dialog
answers, the item runs again with the picked path. Errors still go
to the status bar.

variables_panel_data_sets_ask_off_the_ui_thread clicks both items
with dialogs shown as sheets, as on macOS, imports a CSV and exports the
data sets to the path the dialog answers.

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

@@ -317,10 +317,10 @@ pub fn menu(app: &mut VectorcraftApp, ui: &mut Ui) {
     }
     ui.separator();
     if widgets::menu_item(ui, tl!("Import Data Sets…"), true, false) {
-        import_datasets(app);
+        crate::picks::button(app, import_datasets);
     }
     if widgets::menu_item(ui, tl!("Export Data Sets…"), !vars.is_empty(), false) {
-        export_datasets(app);
+        crate::picks::button(app, export_datasets);
     }
     ui.separator();
     // What the highlighted variable drives, selected — its bindings are left alone.

crates/ui-egui/src/tests_picks.rs

@@ -221,6 +221,33 @@ fn load_profile_asks_off_the_ui_thread() {
     assert!(app.ui.status.contains("/no/such/profile.icc"), "color.loadProfile ran on the path: {}", app.ui.status);
 }
 
+/// The Variables panel menu's Import Data Sets… and Export Data Sets… ask off the UI thread: the
+/// data sets in the file picked are loaded, and the data sets are written to the path the dialog
+/// answers.
+#[test]
+fn variables_panel_data_sets_ask_off_the_ui_thread() {
+    let (mut app, shown, _) = app();
+    app.run("file.new", json!({"width": 100, "height": 80})).unwrap();
+    let dir = std::env::temp_dir().join(format!("vc-picks-data-sets-{}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    let (csv, out) = (dir.join("sets.csv"), dir.join("out.csv"));
+    std::fs::write(&csv, "name,Name\nB,y\n").unwrap();
+    let sets = |app: &VectorcraftApp| app.session.doc().unwrap().doc.variables.datasets.iter().map(|d| d.name.clone()).collect::<Vec<_>>();
+
+    click(&mut app, "Import Data Sets…", crate::panels::variables::menu);
+    assert!(matches!(shown.requests().as_slice(), [PickRequest::Open(_)]));
+    shown.answer(&[&csv.to_string_lossy()]);
+    poll(&mut app);
+    assert_eq!(sets(&app), ["B"], "{}", app.ui.status);
+
+    click(&mut app, "Export Data Sets…", crate::panels::variables::menu);
+    assert!(matches!(shown.requests().as_slice(), [PickRequest::Save(_)]));
+    shown.answer(&[&out.to_string_lossy()]);
+    poll(&mut app);
+    assert!(std::fs::read_to_string(&out).is_ok_and(|text| text.starts_with("name,Name\n")), "{}", app.ui.status);
+    let _ = std::fs::remove_dir_all(dir);
+}
+
 /// The Swatches libraries menu's Other Library… asks off the UI thread; the file picked (another
 /// document) loads as a library and opens in the library panel.
 #[test]