feat: save body and occurrence visibility with the design (#531) (#592)

Hidden bodies, occurrence placements, sketches and origin items are saved with the design and come back when it is reopened. Visibility is still not an undo step, but hiding or showing something now counts as an unsaved change. Additive field under format 16. Fixes #531.

Co-authored-by: jonaswre <jonas.wrede@beyondit.gmbh>

crates/engine/src/cmd/occurrence_tests.rs

@@ -425,6 +425,87 @@ fn instance_styles_follow_source_identity_after_collision_rename_and_pending_mov
     assert!(imported.bodies[0].body.paint().unwrap().faces.iter().any(|f| f.color == [0.0, 1.0, 0.0]));
 }
 
+/// A design file path in a fresh temporary folder (removed by the caller).
+fn temp_design(tag: &str, ext: &str) -> (std::path::PathBuf, String) {
+    let dir = std::env::temp_dir().join(format!("solidcraft-visibility-{tag}-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    std::fs::create_dir_all(&dir).unwrap();
+    let path = dir.join(format!("design.{ext}")).to_string_lossy().to_string();
+    (dir, path)
+}
+
+/// #531: hiding a placement and a body is saved with the design and comes back when it opens.
+/// It is not an undo step (undoing a later feature leaves it hidden), but the design then has
+/// unsaved changes, and showing it again is saved the same way.
+#[test]
+fn hidden_placements_and_bodies_are_saved_with_the_design_but_not_undone() {
+    let (dir, path) = temp_design("saved", "solidcraft");
+    let mut s = Session::default();
+    run(&mut s, "solid.box", json!({"length":4,"width":4,"height":4,"body_name":"Base"}));
+    let (component, first) = created(&mut s, "Part");
+    run(&mut s, "solid.box", json!({"length":2,"width":2,"height":2}));
+    let second = run(&mut s, "occurrence.copy", json!({"occurrence":first,"translate":[20,0,0]}))["occurrence"].as_u64().unwrap();
+    run(&mut s, "component.activate", json!({"component":0}));
+    run(&mut s, "file.save", json!({"path": path}));
+    assert!(!s.is_dirty());
+
+    let undo = s.undo.len();
+    run(&mut s, "browser.visibility", json!({"visible":false,"paths":[[second]]}));
+    run(&mut s, "browser.visibility", json!({"visible":false,"items":["Base"]}));
+    assert_eq!(s.undo.len(), undo, "hiding is not an undo step");
+    assert!(s.is_dirty(), "hiding leaves the design with unsaved changes");
+    run(&mut s, "solid.box", json!({"length":1,"width":1,"height":1,"corner":[50,0,0],"operation":"new","body_name":"Later"}));
+    run(&mut s, "edit.undo", json!({}));
+    assert!(!s.body_visible("Base") && !s.occurrence_visible(&[second]), "undo keeps the hiding");
+
+    run(&mut s, "file.save", json!({}));
+    assert!(!s.is_dirty());
+    run(&mut s, "file.new", json!({}));
+    run(&mut s, "doc.open", json!({"path": path}));
+    assert!(!s.body_visible("Base"), "the hidden body stays hidden");
+    assert!(!s.occurrence_visible(&[second]), "the hidden placement stays hidden");
+    assert!(s.occurrence_visible(&[first]));
+    assert!(s.doc.components.iter().any(|c| c.id == component));
+    assert!(!s.is_dirty(), "an opened design has no unsaved changes");
+    assert!(s.undo.is_empty());
+
+    run(&mut s, "browser.visibility", json!({"visible":true,"folder":"bodies"}));
+    assert!(s.is_dirty());
+    run(&mut s, "file.save", json!({}));
+    run(&mut s, "file.new", json!({}));
+    run(&mut s, "doc.open", json!({"path": path}));
+    assert!(s.body_visible("Base") && s.occurrence_visible(&[second]), "showing again is saved too");
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
+/// #531: designs saved before visibility was kept (no `visibility` in the file) open with
+/// everything shown, and a design with nothing hidden saves exactly as before.
+#[test]
+fn designs_without_saved_visibility_open_unchanged() {
+    let (dir, path) = temp_design("legacy", "json");
+    let mut s = Session::default();
+    run(&mut s, "solid.box", json!({"length":4,"width":4,"height":4,"body_name":"Base"}));
+    let mut legacy: Value = serde_json::from_slice(&solidcraft_io::write_design(&s.doc)).unwrap();
+    assert!(legacy.get("visibility").is_none(), "nothing hidden: no visibility in the file");
+    legacy["format"] = json!("solidcraft/15");
+    std::fs::write(&path, serde_json::to_vec(&legacy).unwrap()).unwrap();
+
+    run(&mut s, "file.new", json!({}));
+    run(&mut s, "doc.open", json!({"path": path}));
+    assert!(s.body_visible("Base"));
+    assert_eq!(s.visibility, crate::Visibility::default());
+    assert!(!s.is_dirty());
+    run(&mut s, "file.save", json!({}));
+    let saved: Value = serde_json::from_slice(&std::fs::read(&path).unwrap()).unwrap();
+    assert!(saved.get("visibility").is_none());
+
+    run(&mut s, "browser.visibility", json!({"visible":false,"items":["Base"]}));
+    run(&mut s, "file.save", json!({}));
+    let saved: Value = serde_json::from_slice(&std::fs::read(&path).unwrap()).unwrap();
+    assert_eq!(saved["visibility"]["hidden_bodies"], json!(["Base"]));
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
 /// Command names for linking another design are a proposal (#533); adjust them to the real API.
 const INSERT_DESIGN: &str = "component.insert_design";
 const UPDATE_LINKS: &str = "component.update_links";