test: failing regression test for #266: Multi-profile solid.extrude with body_name names only the first body (#281)

* test: reproduce #266 (Multi-profile solid.extrude with body_name names only the first body)

* fix: name every body of a multi-body feature after body_name (#266)

A new-body feature that makes more bodies than it was given names now stores Ribs (2),
Ribs (3)... for the rest instead of falling back to generic BodyN names. Command-time only:
saved designs keep their names.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT

* fix: keep body_name list for the multi-body naming step (#266)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT

---------

Co-authored-by: bherbruck <brennen.herbruck@gmail.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/cmd/features.rs

@@ -443,10 +443,33 @@ fn add_feature_in(s: &mut Session, p: &Value, kind: FeatureKind, world: bool) ->
     if !names.is_empty()
         && let Some(f) = s.doc_mut().feature_mut(id)
     {
-        f.body_names = names;
+        f.body_names = names.clone();
     }
     s.active_sketch = None;
     s.refresh();
+    // A feature that makes more bodies than it was given names (a multi-profile extrude with one
+    // `body_name`) names the rest after the first: `Ribs`, `Ribs (2)`, `Ribs (3)`… (#266). The
+    // names are stored on the feature, so recomputes and saved designs keep them.
+    if let Some(base) = names.first().map(|n| n.trim().to_string()).filter(|n| !n.is_empty()) {
+        let st = s.model.state();
+        let made = st.bodies.iter().filter(|b| b.feature == id).count();
+        if made > names.len() {
+            let mut taken: std::collections::BTreeSet<String> = st.bodies.iter().map(|b| b.name.clone()).collect();
+            taken.extend(names.iter().cloned());
+            let mut i = 1usize;
+            while names.len() < made {
+                i += 1;
+                let n = format!("{base} ({i})");
+                if taken.insert(n.clone()) {
+                    names.push(n);
+                }
+            }
+            if let Some(f) = s.doc_mut().feature_mut(id) {
+                f.body_names = names;
+            }
+            s.refresh();
+        }
+    }
     let r = s.model.result(id).cloned();
     if let Some(e) = r.as_ref().and_then(|r| r.error.clone()) {
         return Err(EngineError::Other(e));

crates/engine/src/tests.rs

@@ -2489,6 +2489,21 @@ fn special_files_are_refused_by_every_file_command() {
     let _ = std::fs::remove_dir_all(&dir);
 }
 
+/// Every body a multi-profile `new` extrude creates carries its `body_name`, not a generic BodyN (#266).
+#[test]
+fn multi_profile_extrude_names_every_body_after_body_name() {
+    let mut s = Session::default();
+    run(&mut s, "sketch.create", json!({"plane": "XY", "name": "R"}));
+    for x in [0, 10, 20] {
+        run(&mut s, "sketch.rectangle.two_point", json!({"p0": [x, 0], "p1": [x + 5, 30]}));
+    }
+    run(&mut s, "sketch.finish", json!({}));
+    run(&mut s, "solid.extrude", json!({"distance": "10", "operation": "new_body", "body_name": "Ribs"}));
+    let names: Vec<String> = s.model.state().bodies.iter().map(|b| b.name.clone()).collect();
+    assert!(names.iter().all(|n| n.starts_with("Ribs")), "{names:?}");
+    assert!(rel(volume(&mut s), 4500.0) < 1e-6);
+}
+
 /// Renaming one pattern copy leaves the other copies' names alone (#265).
 #[test]
 fn renaming_a_pattern_copy_keeps_the_other_copies_names() {