Pipelines cause Z-fighting (#1976)

Bug: You can see here that the two programs under tests/ are equivalent, just one uses 
pipelines and one always assigns to a new sketchgroup. However, the pipeline
produces weird visual bugs. Jess did a git bisect to figure out this was the problem that
Mike was experiencing, around weird visual artifacts with filleting.

Ultimately the bug was that my rewritten `execute_pipe_body` function was executing
the first expression of the pipeline body twice! In most unit tests this didn't matter,
because the first expression in a pipeline was startSketchAt. No big deal to run that
twice. However, in Mike's program, the first expression was `make_circle` or `pentagon`,
user-defined functions that sent a lot of API calls. This meant the pipeline duplicated a lot
of geometry, causing Z-fighting and weird artifacts.

src/wasm-lib/tests/executor/inputs/pentagon_fillet_desugar.kcl

@@ -0,0 +1,42 @@
+fn make_circle = (face, tag, pos, radius) => {
+  const sg0 = startSketchOn(face, tag)
+  const sg1 = startProfileAt([pos[0] + radius, pos[1]], sg0)
+  const sg2 =  arc({
+       angle_end: 360,
+       angle_start: 0,
+       radius: radius
+     }, sg1, 'arc-' + tag)
+  return close(sg2)
+}
+
+fn pentagon = (len) => {
+  const sg3 = startSketchOn('XY')
+  const sg4 = startProfileAt([-len / 2, -len / 2], sg3)
+  const sg5 = angledLine({ angle: 0, length: len }, sg4, 'a')
+  const sg6 = angledLine({
+       angle: segAng('a', sg5) + 180 - 108,
+       length: len
+     },sg5, 'b')
+  const sg7 = angledLine({
+       angle: segAng('b', sg6) + 180 - 108,
+       length: len
+     }, sg6, 'c')
+  const sg8 = angledLine({
+       angle: segAng('c', sg7) + 180 - 108,
+       length: len
+     }, sg7, 'd')
+  return angledLine({
+       angle: segAng('d', sg8) + 180 - 108,
+       length: len
+     }, sg8)
+}
+
+const p = pentagon(48)
+const pe = extrude(30, p)
+
+const plumbus0 = make_circle(pe, 'a', [0, 0], 9)
+const plumbus1 = extrude(18, plumbus0)
+const plumbus2 = fillet({
+       radius: 0.5,
+       tags: ['arc-a', getOppositeEdge('arc-a', plumbus1)]
+     }, plumbus1)

src/wasm-lib/tests/executor/inputs/pentagon_fillet_sugar.kcl

@@ -0,0 +1,46 @@
+fn make_circle = (face, tag, pos, radius) => {
+  const sg = startSketchOn(face, tag)
+  |> startProfileAt([pos[0] + radius, pos[1]], %)
+  |> arc({
+       angle_end: 360,
+       angle_start: 0,
+       radius: radius
+     }, %, 'arc-' + tag)
+  |> close(%)
+
+  return sg
+}
+
+fn pentagon = (len) => {
+  const sg = startSketchOn('XY')
+  |> startProfileAt([-len / 2, -len / 2], %)
+  |> angledLine({ angle: 0, length: len }, %, 'a')
+  |> angledLine({
+       angle: segAng('a', %) + 180 - 108,
+       length: len
+     }, %, 'b')
+  |> angledLine({
+       angle: segAng('b', %) + 180 - 108,
+       length: len
+     }, %, 'c')
+  |> angledLine({
+       angle: segAng('c', %) + 180 - 108,
+       length: len
+     }, %, 'd')
+  |> angledLine({
+       angle: segAng('d', %) + 180 - 108,
+       length: len
+     }, %)
+
+  return sg
+}
+
+const p = pentagon(48)
+  |> extrude(30, %)
+
+const plumbus0 = make_circle(p, 'a', [0, 0], 9)
+  |> extrude(18, %)
+  |> fillet({
+       radius: 0.5,
+       tags: ['arc-a', getOppositeEdge('arc-a', %)]
+     }, %)

src/wasm-lib/tests/executor/main.rs

@@ -111,16 +111,34 @@ const part002 = startSketchOn(part001, "here")
         .unwrap();
     twenty_twenty::assert_image("tests/executor/outputs/sketch_on_face.png", &result, 0.999);
 }
+
 #[tokio::test(flavor = "multi_thread")]
 async fn serial_test_riddle_small() {
     let code = include_str!("inputs/riddle_small.kcl");
-
     let result = execute_and_snapshot(code, kittycad::types::UnitLength::Mm)
         .await
         .unwrap();
     twenty_twenty::assert_image("tests/executor/outputs/riddle_small.png", &result, 0.999);
 }
 
+#[tokio::test(flavor = "multi_thread")]
+async fn serial_test_pentagon_fillet_desugar() {
+    let code = include_str!("inputs/pentagon_fillet_desugar.kcl");
+    let result = execute_and_snapshot(code, kittycad::types::UnitLength::Cm)
+        .await
+        .unwrap();
+    twenty_twenty::assert_image("tests/executor/outputs/pentagon_fillet_desugar.png", &result, 0.999);
+}
+
+#[tokio::test(flavor = "multi_thread")]
+async fn serial_test_pentagon_fillet_sugar() {
+    let code = include_str!("inputs/pentagon_fillet_sugar.kcl");
+    let result = execute_and_snapshot(code, kittycad::types::UnitLength::Cm)
+        .await
+        .unwrap();
+    twenty_twenty::assert_image("tests/executor/outputs/pentagon_fillet_sugar.png", &result, 0.999);
+}
+
 #[tokio::test(flavor = "multi_thread")]
 async fn serial_test_sketch_on_face_start() {
     let code = r#"fn cube = (pos, scale) => {
@@ -1898,12 +1916,12 @@ const plumbus0 = make_circle(p, 'a', [0, 0], 1.5)
        tags: ['arc-a', getOppositeEdge('arc-a', %)]
      }, %)
 
-const plumbus1 = make_circle(p, 'b', [0, 0], 1.5)
-  |> extrude(3, %)
-  |> fillet({
-       radius: 0.5,
-       tags: ['arc-b', getOppositeEdge('arc-b', %)]
-     }, %)
+// const plumbus1 = make_circle(p, 'b', [0, 0], 1.5)
+//   |> extrude(3, %)
+//   |> fillet({
+//        radius: 0.5,
+//        tags: ['arc-b', getOppositeEdge('arc-b', %)]
+//      }, %)
 "#;
 
     let result = execute_and_snapshot(code, kittycad::types::UnitLength::Mm)