Joint drives say when they move nothing; drive values in degrees; quiet replies (#1304)

joint.drive answers moved, and a reason (with unconnected) when the joint can move nothing; motion.play answers moved and unmoved; joint.list answers floating chains. joint.drive values come back in joint.list's shape (deg/mm). quiet: true trims joint answers and motion.play poses. A single value keeps a joint's other values. Drive Joints shows the floating case (drive.unconnected, all locales).

crates/ui-egui/src/dialogs_assembly_tests.rs

@@ -415,7 +415,7 @@ fn drive_says_where_a_loop_stopped_it() {
     // Past its toggle position (about +50.4° from where it stands).
     ask(&mut d, "100 deg");
     let b = world_preview(&app.session, &apply_commands(&app, &d).unwrap(), colors).unwrap().unwrap();
-    let why = b.stopped.as_ref().and_then(|r| drive_stop(&app.session, r)).unwrap();
+    let why = b.stopped.as_ref().and_then(drive_stop).unwrap();
     assert!(why.starts_with("Stopped at 50.") && why.contains("can't close any further"), "{why}");
     // OK drives it there and says so.
     crate::dialogs::run_dialog(&mut app, &d).unwrap();
@@ -431,6 +431,32 @@ fn drive_says_which_parts_a_contact_set_stopped() {
     app.run("joint.create", json!({"type": "slider", "a": at("A"), "b": at("B"), "flip": true, "name": "Rail"})).unwrap();
     app.run("contact.create", json!({"occurrences": ["A:1", "B:1"]})).unwrap();
     let r = app.run("joint.drive", json!({"joint": "Rail", "value": -20})).unwrap();
-    let why = drive_stop(&app.session, &r).unwrap();
+    let why = drive_stop(&r).unwrap();
     assert!(why.starts_with("Stopped at -1") && why.contains("A:1") && why.contains("B:1") && why.contains("would pass through"), "{why}");
 }
+
+/// A drive whose joint is joined to nothing grounded moves nothing: the preview row and the
+/// status line name the part that floats.
+#[test]
+fn drive_says_when_its_joint_is_joined_to_nothing_grounded() {
+    let mut app = two_boxes();
+    for (name, x) in [("C", 100), ("D", 130)] {
+        app.run("component.activate", json!({"component": "root"})).unwrap();
+        app.run("component.create", json!({ "name": name })).unwrap();
+        app.run("solid.box", json!({"length": 20, "width": 20, "height": 10, "corner": [x, 0, 0]})).unwrap();
+    }
+    let at = |o: &str, x: f64| json!({"occurrence": o, "point": [x, 10, 5], "z": [1, 0, 0]});
+    app.run("joint.create", json!({"type": "slider", "a": at("A", 30.0), "b": at("B", 30.0), "flip": true, "name": "Rail"})).unwrap();
+    app.run("joint.create", json!({"type": "revolute", "a": at("C", 130.0), "b": at("D", 130.0), "flip": true, "name": "Turn"})).unwrap();
+    let turn = app.session.doc.assembly.joints.iter().find(|j| j.name == "Turn").unwrap().id;
+    let mut d = drive_joint(&app, turn).unwrap();
+    if let Kind::Assembly(Asm::Drive { values, .. }) = &mut d.kind {
+        values[0] = "45 deg".into();
+    }
+    let colors = crate::preview::Colors { body: [1, 1, 1, 255], added: [2, 2, 2, 255], removed: [3, 3, 3, 100], edge: [0, 0, 0, 255] };
+    let b = world_preview(&app.session, &apply_commands(&app, &d).unwrap(), colors).unwrap().unwrap();
+    let why = b.stopped.as_ref().and_then(drive_stop).unwrap();
+    assert!(why.starts_with("Moves nothing") && why.contains("C:1"), "{why}");
+    crate::dialogs::run_dialog(&mut app, &d).unwrap();
+    assert_eq!(app.status.clone().map(|(status, _, error)| (status, error)), Some((why, false)));
+}