Preferences › Sketch: auto-projection holds across designs (#680) (#959)

Session::replace_design keeps auto_project when file.new, doc.open and doc.recover swap in another design, and the UI keeps it across tabs, adopt and the last-tab close. Regression tests in engine (sketch_project) and ui-egui (documents).

crates/engine/src/cmd/file.rs

@@ -51,7 +51,7 @@ pub static COMMANDS: &[CommandSpec] = &[
 
 fn new_doc(s: &mut Session, p: &Value) -> Result<Value> {
     let name = str_(p, "name").unwrap_or("Untitled");
-    *s = Session::new(Document::new(name));
+    s.replace_design(Session::new(Document::new(name)));
     Ok(json!({"name": name}))
 }
 
@@ -130,7 +130,7 @@ fn open(s: &mut Session, p: &Value) -> Result<Value> {
         let mut fresh = Session::new(Document::new(&stem));
         let r = if solidcraft_io::is_step_path(path) { add_step(&mut fresh, path, None)? } else { add_mesh(&mut fresh, path, None)? };
         fresh.undo.clear();
-        *s = fresh;
+        s.replace_design(fresh);
         let errors = s.model.results.iter().filter(|r| r.error.is_some()).count();
         return Ok(json!({"path": path, "features": s.doc.features.len(), "errors": errors, "bodies": r["bodies"], "warnings": r["warnings"]}));
     }
@@ -138,7 +138,7 @@ fn open(s: &mut Session, p: &Value) -> Result<Value> {
     if let Some(stem) = default_name_for(&doc.name, path) {
         doc.name = stem;
     }
-    *s = Session::new(doc);
+    s.replace_design(Session::new(doc));
     s.path = Some(path.to_string());
     let errors = s.model.results.iter().filter(|r| r.error.is_some()).count();
     Ok(json!({"path": path, "features": s.doc.features.len(), "errors": errors, "name": s.doc.name}))
@@ -421,7 +421,7 @@ fn recover(s: &mut Session, p: &Value) -> Result<Value> {
     if let Some(stem) = entry.path.as_deref().and_then(|path| default_name_for(&doc.name, path)) {
         doc.name = stem;
     }
-    *s = Session::new(doc);
+    s.replace_design(Session::new(doc));
     s.path = entry.path.clone();
     s.mark_unsaved();
     if bool_(p, "discard").unwrap_or(false) {

crates/engine/src/cmd/sketch_project_tests.rs

@@ -148,6 +148,30 @@ fn auto_project_can_be_turned_off() {
     assert!(r["projected"].is_null());
 }
 
+/// #680: auto-projection is a preference, not part of a design: turning it off holds for the
+/// next design started or opened in the session (`doc.recover` replaces the session the same way).
+#[test]
+fn auto_project_off_holds_for_designs_started_and_opened() {
+    let dir = std::env::temp_dir().join(format!("solidcraft-auto-project-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    std::fs::create_dir_all(&dir).unwrap();
+    let file = dir.join("box.solidcraft");
+    let mut s = Session::default();
+    box_part(&mut s);
+    run(&mut s, "file.save_as", json!({"path": file.to_string_lossy()}));
+    run(&mut s, "sketch.auto_project", json!({"value": false}));
+    run(&mut s, "file.new", json!({}));
+    assert!(!s.auto_project, "file.new");
+    run(&mut s, "doc.open", json!({"path": file.to_string_lossy()}));
+    assert!(!s.auto_project, "doc.open");
+    let r = run(&mut s, "sketch.create", json!({"plane": {"face": [20, 15, 20]}}));
+    assert!(r["projected"].is_null(), "{r}");
+    run(&mut s, "sketch.auto_project", json!({"value": true}));
+    run(&mut s, "file.new", json!({}));
+    assert!(s.auto_project, "turned back on, it stays on");
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
 #[test]
 fn project_edges_bodies_sketches_and_origin() {
     let mut s = Session::default();