fix: fillet fit review follow-ups (#404)

* fix: fillet fit review follow-ups

From the review of #388 (merged before these landed):
- The Fillet dialog's Applied Radius showed nothing when editing a fillet
  that was already reduced: the preview found the radius by diffing the
  states before and after. The engine's preview now keeps the command
  replies, and the dialog reads the radius of the feature they name.
- Pattern copies of a reduced fillet try the radius the original was
  reduced to first, instead of each searching again (up to 16 fillets).
- fit: reduce with a chord or variable radius is refused instead of being
  silently ignored.
- One helper appends a note to a feature's warning; too_large is imported
  like unsupported in the loop and curve blends.

Refs #293

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01TWc1smHYwTSVrVc8SNvS44

* Use the solidcraft_doc crate name after the rename

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01HWLPLy7ug7URSK5WybjRNa

---------

Co-authored-by: Claude Opus 5.5 <[email protected]>
Co-authored-by: bherbruck <[email protected]>

crates/engine/src/cmd/features.rs

@@ -790,6 +790,9 @@ fn fillet(s: &mut Session, p: &Value) -> Result<Value> {
         Some("reduce") => solidcraft_doc::FilletFit::Reduce,
         Some(o) => return Err(bad(cmd, format!("unknown fit `{o}` (exact or reduce)"))),
     };
+    if fit == solidcraft_doc::FilletFit::Reduce && !style.is_constant() {
+        return Err(bad(cmd, "`fit: reduce` takes a constant radius"));
+    }
     let mut out = add_feature(s, p, FeatureKind::Fillet { edges, radius, body: str_(p, "body").map(str::to_string), style, fit })?;
     // The radius the fillet used, when `fit: reduce` reduced it.
     if let Some(id) = out.get("feature").and_then(Value::as_u64)

crates/engine/src/lib.rs

@@ -157,6 +157,8 @@ pub struct Preview {
     pub before: Arc<ModelState>,
     /// The model after the commands.
     pub after: Arc<ModelState>,
+    /// What each command replied (as `execute` returns it).
+    pub replies: Vec<Value>,
 }
 
 /// Prepared world geometry depends on design/model identity and placement context, not
@@ -693,12 +695,12 @@ impl Session {
     /// A `timeline.redefine` is shown even while the timeline is rolled back to the feature
     /// being edited.
     pub fn preview(&self, commands: &[(String, Value)]) -> Result<Preview> {
-        self.scratch().preview_in_place(commands).map(|after| Preview { before: self.model.state(), after: after.model.state() })
+        self.scratch().preview_in_place(commands).map(|(after, replies)| Preview { before: self.model.state(), after: after.model.state(), replies })
     }
 
     /// The same evaluated preview in occurrence coordinates, including uncaptured moves.
     pub fn preview_world(&self, commands: &[(String, Value)]) -> Result<Preview> {
-        self.scratch().preview_in_place(commands).map(|after| Preview { before: self.world_state(), after: after.world_state() })
+        self.scratch().preview_in_place(commands).map(|(after, replies)| Preview { before: self.world_state(), after: after.world_state(), replies })
     }
 
     /// World preview with each session's visibility applied, including new body placements.
@@ -709,15 +711,17 @@ impl Session {
             shown.bodies.retain(|body| session.body_visible(&body.name));
             Arc::new(shown)
         };
-        self.scratch().preview_in_place(commands).map(|after| Preview { before: visible(self), after: visible(&after) })
+        self.scratch().preview_in_place(commands).map(|(after, replies)| Preview { before: visible(self), after: visible(&after), replies })
     }
 
-    fn preview_in_place(mut self, commands: &[(String, Value)]) -> Result<Self> {
+    fn preview_in_place(mut self, commands: &[(String, Value)]) -> Result<(Self, Vec<Value>)> {
         if commands.is_empty() {
             return Err(EngineError::Other("nothing to preview".into()));
         }
+        let mut replies = Vec::with_capacity(commands.len());
         for (id, params) in commands {
             let r = self.execute(id, params)?;
+            replies.push(r.clone());
             if id == "timeline.redefine"
                 && let Some(fid) = r.get("feature").and_then(Value::as_u64)
                 && let Some(idx) = self.doc.feature_index(fid)
@@ -730,7 +734,7 @@ impl Session {
                 }
             }
         }
-        Ok(self)
+        Ok((self, replies))
     }
 
     /// Measure one or two selections (see `inspect.measure` with `items`); errors come back as

crates/engine/src/tests.rs

@@ -2815,6 +2815,21 @@ fn fillet_fit_reduce_uses_the_largest_radius_that_fits() {
     // Saved only when set.
     let json = serde_json::to_string(&s.doc.features).unwrap();
     assert_eq!(json.matches("\"fit\":\"reduce\"").count(), 1, "{json}");
-    // An unknown mode is refused.
+    // An unknown mode is refused, and so is reduce with a radius that is not constant.
     assert!(s.execute("solid.fillet", &json!({"edges": mids, "radius": 1, "fit": "taper"})).is_err());
+    assert!(s.execute("solid.fillet", &json!({"edges": mids, "radius": 1, "fit": "reduce", "type": "chord"})).is_err());
+}
+
+#[test]
+fn a_pattern_of_a_reduced_fillet_rounds_each_copy_alike() {
+    // #293: a 6 mm wide post on a plate, its four vertical edges at 3.5 reduced to 3, patterned
+    // three times: every copy is a full round.
+    let mut s = Session::default();
+    run(&mut s, "solid.box", json!({"length": 60, "width": 20, "height": 2}));
+    run(&mut s, "solid.box", json!({"length": 14, "width": 6, "height": 10, "corner": [2, 7, 2], "operation": "join", "name": "Post"}));
+    let mids = json!([[2, 7, 7], [16, 7, 7], [2, 13, 7], [16, 13, 7]]);
+    run(&mut s, "solid.fillet", json!({"edges": mids, "radius": 3.5, "fit": "reduce", "name": "Round"}));
+    run(&mut s, "solid.pattern.rectangular", json!({"features": ["Post", "Round"], "dir1": [1, 0, 0], "count1": 3, "spacing1": 20}));
+    let expect = 60.0 * 20.0 * 2.0 + 3.0 * (840.0 - (4.0 - PI) * 9.0 * 10.0);
+    assert!(rel(volume(&mut s), expect) < 2e-4, "{} vs {expect}", volume(&mut s));
 }