Profiles picked by index are kept by the curves around them: add_feature turns profile indices into the curve ids of each profile's outer loop (Extrude, Revolve, Sweep, Loft, Emboss, Sheet Base, Patch), so a face sketch whose projected outline is rebuilt still extrudes the picked region; a profile that is gone is an error on the feature, never another pick

Fixes #30

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT

crates/doc/src/document.rs

@@ -1078,6 +1078,20 @@ impl FeatureKind {
     /// Every expression the feature uses.
     /// Points on faces the feature refers to (shell, draft, offset and replace faces, a hole's
     /// placement), for persistent face names.
+    /// The feature's profile selections, each with its sketch.
+    pub fn profile_sels_mut(&mut self) -> Vec<(u64, &mut ProfileSel)> {
+        match self {
+            FeatureKind::Extrude { sketch, profiles, .. }
+            | FeatureKind::Revolve { sketch, profiles, .. }
+            | FeatureKind::Sweep { sketch, profiles, .. }
+            | FeatureKind::Emboss { sketch, profiles, .. }
+            | FeatureKind::SheetBase { sketch, profiles, .. } => vec![(*sketch, profiles)],
+            FeatureKind::Patch { sketch: Some(sk), profiles, .. } => vec![(*sk, profiles)],
+            FeatureKind::Loft { sections, .. } => sections.iter_mut().filter(|s| s.point.is_none()).map(|s| (s.sketch, &mut s.profiles)).collect(),
+            _ => Vec::new(),
+        }
+    }
+
     pub fn face_points_mut(&mut self) -> Vec<&mut Vec3> {
         match self {
             FeatureKind::Shell { faces, .. }

crates/engine/src/cmd/features.rs

@@ -209,6 +209,37 @@ pub(super) fn feature_sketch(s: &Session, p: &Value, cmd: &str) -> Result<u64> {
         .ok_or_else(|| bad(cmd, "there is no sketch to use (create one first)"))
 }
 
+/// Profile indices become the curve ids of each profile's loops as the sketch is now solved.
+fn stable_profiles(s: &Session, kind: &mut FeatureKind) -> Result<()> {
+    let st = s.model.state();
+    'sels: for (sketch, sel) in kind.profile_sels_mut() {
+        let ProfileSel::Indices { indices } = sel else { continue };
+        let Some(ss) = st.sketch(sketch) else { continue };
+        let mut loops = Vec::with_capacity(indices.len());
+        for i in indices.iter() {
+            let pr = ss
+                .profiles
+                .get(*i)
+                .ok_or_else(|| EngineError::Other(format!("no profile {i} in sketch `{}` (it has {})", ss.name, ss.profiles.len())))?;
+            // Two profiles with the same outer curves (one inside the other's holes cannot be):
+            // keep the index then.
+            if pr.outer_curves.is_empty() || ss.profiles.iter().filter(|q| same_loop(&q.outer_curves, &pr.outer_curves)).count() != 1 {
+                continue 'sels;
+            }
+            loops.push(pr.outer_curves.clone());
+        }
+        *sel = ProfileSel::Curves { loops };
+    }
+    Ok(())
+}
+
+fn same_loop(a: &[String], b: &[String]) -> bool {
+    let (mut a, mut b) = (a.to_vec(), b.to_vec());
+    a.sort();
+    b.sort();
+    a == b
+}
+
 pub(super) fn profiles(p: &Value, cmd: &str) -> Result<ProfileSel> {
     let Some(v) = p.get("profiles") else { return Ok(ProfileSel::All) };
     match v {
@@ -270,6 +301,9 @@ pub(super) fn add_feature(s: &mut Session, p: &Value, kind: FeatureKind) -> Resu
             *e = doc.with_design_unit(e, k);
         }
     }
+    // Profiles picked by index are kept by the curves around them: a recompute can renumber a
+    // sketch's profiles (a face sketch's projected outline rebuilt), never the curves.
+    stable_profiles(s, &mut kind)?;
     // Blends remember where their edges sat, to find them again after upstream edits.
     let (refs, names) = match &kind {
         FeatureKind::Fillet { edges, body, .. } | FeatureKind::Chamfer { edges, body, .. } => {

crates/engine/src/lib.rs

@@ -433,6 +433,8 @@ mod delete_face_tests;
 #[cfg(test)]
 mod extent_tests;
 #[cfg(test)]
+mod profile_refs_tests;
+#[cfg(test)]
 mod split_face_tests;
 #[cfg(test)]
 mod tests;

crates/engine/src/profile_refs_tests.rs

@@ -0,0 +1,87 @@
+//! Profile picks survive recomputes (#30): picked by index, they are kept by the curves around
+//! them, so a face sketch whose projected outline is rebuilt still extrudes the same region.
+
+use serde_json::{Value, json};
+
+use crate::Session;
+
+fn run(s: &mut Session, id: &str, p: Value) -> Value {
+    match s.execute(id, &p) {
+        Ok(v) => v,
+        Err(e) => panic!("{id} {p}: {e}"),
+    }
+}
+
+/// The demo enclosure (80 × 60 × 30, rounded, shelled) with a USB port cut through a side, the
+/// port picked by index as the Extrude dialog does.
+fn enclosure() -> Session {
+    let mut s = Session::default();
+    let script = json!([
+        {"command": "parameters.change", "params": {"name": "width", "expression": "80 mm", "comment": "outside, X"}},
+        {"command": "parameters.change", "params": {"name": "depth", "expression": "60 mm", "comment": "outside, Y"}},
+        {"command": "parameters.change", "params": {"name": "height", "expression": "30 mm"}},
+        {"command": "parameters.change", "params": {"name": "wall", "expression": "2 mm"}},
+        {"command": "sketch.create", "params": {"plane": "XY", "name": "Outline"}},
+        {"command": "sketch.rectangle.center", "params": {"center": [0, 0], "corner": [40, 30]}},
+        {"command": "sketch.constraint.coincident", "params": {"a": "p5", "b": "origin"}},
+        {"command": "sketch.dimension", "params": {"entities": ["l1"], "value": "width"}},
+        {"command": "sketch.dimension", "params": {"entities": ["l2"], "value": "depth"}},
+        {"command": "sketch.finish", "params": {}},
+        {"command": "solid.extrude", "params": {"distance": "height", "body_name": "Enclosure"}},
+        {"command": "solid.fillet", "params": {"edges": [[40, 30, 15], [-40, 30, 15], [-40, -30, 15], [40, -30, 15]], "radius": 6}},
+        {"command": "solid.shell", "params": {"faces": [[0, 0, 30]], "thickness": "wall"}},
+        {"command": "sketch.create", "params": {"plane": {"face": [40, 10, 20]}, "name": "USB port"}},
+        {"command": "sketch.rectangle.center", "params": {"center": [0, 12], "corner": [6, 15.5]}},
+        {"command": "sketch.finish", "params": {}},
+        {"command": "solid.extrude", "params": {"distance": "-wall", "operation": "cut", "profiles": [1]}}
+    ]);
+    s.run_script(&script).unwrap();
+    s
+}
+
+fn bodies(s: &Session) -> Vec<(String, f64)> {
+    s.model.state().bodies.iter().map(|b| (b.name.clone(), b.body.tessellate(1e-2).unwrap().measure().volume)).collect()
+}
+
+#[test]
+fn a_port_picked_by_index_stays_a_cut_after_a_width_change() {
+    let mut s = enclosure();
+    let f = s.doc.features.last().unwrap();
+    let solvecraft_doc::FeatureKind::Extrude { profiles, .. } = &f.kind else { panic!("{:?}", f.kind) };
+    assert!(matches!(profiles, solvecraft_doc::ProfileSel::Curves { .. }), "stored by curves: {profiles:?}");
+    let before = bodies(&s);
+    assert_eq!(before.len(), 1, "{before:?}");
+    run(&mut s, "parameters.change", json!({"name": "width", "expression": "100 mm"}));
+    let after = bodies(&s);
+    assert_eq!(after.len(), 1, "the port is still a cut, not a new body: {after:?}");
+    // The longer box less the same port: more wall and floor, the port still taken out.
+    assert!(after[0].1 > before[0].1 + 1000.0, "{before:?} {after:?}");
+    let id = s.doc.features.last().unwrap().id;
+    assert!(s.model.result(id).is_some_and(|r| r.error.is_none()), "{:?}", s.model.result(id));
+}
+
+/// A pick the sketch no longer has is an error on the feature, never a different profile.
+#[test]
+fn a_lost_profile_is_an_error_not_another_pick() {
+    let mut s = Session::default();
+    run(&mut s, "sketch.create", json!({"plane": "XY", "name": "S"}));
+    run(&mut s, "sketch.rectangle.two_point", json!({"p0": [0, 0], "p1": [10, 10], "ids": ["a", "b", "c", "d"]}));
+    run(&mut s, "sketch.circle.center", json!({"center": [30, 5], "radius": 3, "id": "ring"}));
+    run(&mut s, "sketch.finish", json!({}));
+    let ring = s.model.state().sketches[0].profiles.iter().position(|p| p.outer_curves == ["ring"]).unwrap();
+    run(&mut s, "solid.extrude", json!({"sketch": "S", "profiles": [ring], "distance": 5}));
+    let n = s.model.state().bodies.len();
+    assert_eq!(n, 1);
+    // Delete the picked circle: the extrude fails with a message instead of taking the square.
+    let sk = s.doc.find_feature("S").unwrap().id;
+    let picked = match &s.doc.features.last().unwrap().kind {
+        solvecraft_doc::FeatureKind::Extrude { profiles: solvecraft_doc::ProfileSel::Curves { loops }, .. } => loops[0].clone(),
+        k => panic!("{k:?}"),
+    };
+    run(&mut s, "sketch.edit", json!({"sketch": sk}));
+    run(&mut s, "sketch.delete", json!({"entities": picked}));
+    run(&mut s, "sketch.finish", json!({}));
+    assert!(s.model.state().bodies.is_empty(), "no silent re-pick: {:?}", bodies(&s));
+    let id = s.doc.features.last().unwrap().id;
+    assert!(s.model.result(id).is_some_and(|r| r.error.is_some()), "{:?}", s.model.result(id));
+}