Project: a refusal that names no body names the kind alone (#10626) (#10859)

The refusal of sketch.project ended in "face of " with nothing after the
"of" when the reference named no body: a picked face, edge or vertex is
found by its geometry, so the body it belongs to is not in the reference.

LinkSource::describe() now drops the "of <body>" when there is no body to
name and names the kind alone ("face", "edge", "vertex", "spun
profile", "isoparametric curve"). A source that names a body keeps its
name.

Only the text changes: the command refuses exactly what it refused before.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/engine/src/cmd/sketch_project_tests.rs

@@ -932,9 +932,13 @@ fn projecting_what_the_face_sketch_already_shows_adds_no_second_copy() {
     let border = shown(&mut s);
     assert_eq!(border.0, 8, "four sides and four rounded corners");
     let corner = 5.0 - 5.0 * std::f64::consts::FRAC_1_SQRT_2;
-    for refs in [json!([{"face":[20,15,10]}]), json!([{"edge":[20,0,10]}]), json!([{"edge":[corner,corner,10]}])] {
+    // These references name no body, so the refusal names the kind alone: it must not end in
+    // "face of " with nothing after the "of" (#4929).
+    let cases = [(json!([{"face":[20,15,10]}]), "face"), (json!([{"edge":[20,0,10]}]), "edge"), (json!([{"edge":[corner,corner,10]}]), "edge")];
+    for (refs, what) in cases {
         let e = s.execute("sketch.project", &json!({"refs": refs})).unwrap_err().to_string();
         assert!(e.contains("already projected"), "{refs}: {e}");
+        assert!(e.ends_with(&format!("already projected into this sketch: {what}")), "{refs}: {e}");
         assert_eq!(shown(&mut s), border, "{refs}");
     }
     // Something new still projects, and alongside it a reference already shown is skipped.

crates/sketch/src/link.rs

@@ -134,10 +134,10 @@ impl LinkSource {
     /// Short description for messages and the browser.
     pub fn describe(&self) -> String {
         match self {
-            LinkSource::Edge { body, .. } => format!("edge of {body}"),
-            LinkSource::Face { body, .. } => format!("face of {body}"),
+            LinkSource::Edge { body, .. } => of_body("edge", body),
+            LinkSource::Face { body, .. } => of_body("face", body),
             LinkSource::Body { body } => body.clone(),
-            LinkSource::Vertex { body, .. } => format!("vertex of {body}"),
+            LinkSource::Vertex { body, .. } => of_body("vertex", body),
             LinkSource::SketchCurve { curve, .. } => format!("sketch curve {curve}"),
             LinkSource::SketchPoint { point, .. } => format!("sketch point {point}"),
             LinkSource::Origin => "origin".into(),
@@ -146,8 +146,8 @@ impl LinkSource {
             LinkSource::Plane { name } => format!("{name} plane"),
             LinkSource::OnSurface { curve, .. } => format!("{curve} on a face"),
             LinkSource::Intersection { a, b } => format!("intersection of {} and {}", a.describe(), b.describe()),
-            LinkSource::Spun { body, .. } => format!("spun profile of {body}"),
-            LinkSource::Iso { body, .. } => format!("isoparametric curve of {body}"),
+            LinkSource::Spun { body, .. } => of_body("spun profile", body),
+            LinkSource::Iso { body, .. } => of_body("isoparametric curve", body),
             LinkSource::Text { text, .. } => format!("text \"{}\"", text.chars().take(20).collect::<String>()),
         }
     }
@@ -178,6 +178,13 @@ impl LinkSource {
     }
 }
 
+/// The description of a source that names a body: "face of Body1", or the kind alone when the
+/// reference names no body (a picked face is found by its geometry, and the body it belongs
+/// to is not named in the reference).
+fn of_body(kind: &str, body: &str) -> String {
+    if body.is_empty() { kind.to_string() } else { format!("{kind} of {body}") }
+}
+
 /// Half length of the line a sketch axis link produces.
 pub const SKETCH_AXIS_HALF: f64 = 100.0;
 

crates/sketch/src/tests.rs

@@ -949,6 +949,25 @@ fn links_update_in_place_rebuild_and_break() {
     assert_eq!(back.link(&j3).unwrap().kind, LinkKind::Intersect);
 }
 
+/// A reference that names no body describes itself by its kind alone: the message must not
+/// end in "face of " with nothing after the "of" (#4929).
+#[test]
+fn a_source_without_a_body_name_names_its_kind_alone() {
+    use solidcraft_geom::Vec3;
+    let at = Vec3::ZERO;
+    for (source, expected) in [
+        (LinkSource::Edge { body: String::new(), at }, "edge"),
+        (LinkSource::Face { body: String::new(), at }, "face"),
+        (LinkSource::Vertex { body: String::new(), at }, "vertex"),
+        (LinkSource::Iso { body: String::new(), at, dir: "u".into() }, "isoparametric curve"),
+        (LinkSource::Spun { body: String::new(), origin: at, dir: Vec3::X }, "spun profile"),
+    ] {
+        assert_eq!(source.describe(), expected, "{source:?}");
+    }
+    // A named body keeps its name.
+    assert_eq!(LinkSource::Face { body: "Body1".into(), at }.describe(), "face of Body1");
+}
+
 /// Many independent constrained rectangles solve quickly (per-component work).
 #[test]
 fn large_sketch_solves_fast() {