Finish error propagation for Minkowski, SplitByPlane, Mirror (#1474) (#1659)

Finish error propagation for Minkowski, SplitByPlane, Mirror

Three methods silently dropped errored-input status:

- MinkowskiSum / MinkowskiDifference: no status check before
  Impl::Minkowski.
- SplitByPlane: if (IsEmpty()) early-return returned default
  Manifold() pair; errored manifolds are empty, so error was lost.
- Mirror: zero-length normal path returned empty Manifold() without
  honoring input error.

All use the standard PropagateStatus pattern before the early return.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/manifold.cpp

@@ -493,6 +493,9 @@ Manifold Manifold::Transform(const mat3x4& m) const {
  * @param normal The normal vector of the plane to be mirrored over
  */
 Manifold Manifold::Mirror(vec3 normal) const {
+  auto leafImpl = GetCsgLeafNode().GetImpl();
+  if (leafImpl->status_ != Error::NoError)
+    return PropagateStatus(leafImpl->status_);
   if (la::length(normal) == 0.) {
     return Manifold();
   }
@@ -893,6 +896,11 @@ std::pair<Manifold, Manifold> Manifold::Split(const Manifold& cutter) const {
  */
 std::pair<Manifold, Manifold> Manifold::SplitByPlane(
     vec3 normal, double originOffset) const {
+  auto leafImpl = GetCsgLeafNode().GetImpl();
+  if (leafImpl->status_ != Error::NoError) {
+    Manifold err = PropagateStatus(leafImpl->status_);
+    return {err, err};
+  }
   if (IsEmpty()) return {Manifold(), Manifold()};
   return Split(Halfspace(BoundingBox(), normal, originOffset));
 }
@@ -921,7 +929,9 @@ Manifold Manifold::TrimByPlane(vec3 normal, double originOffset) const {
  */
 Manifold Manifold::MinkowskiSum(const Manifold& other) const {
   auto aImpl = GetCsgLeafNode().GetImpl();
+  if (aImpl->status_ != Error::NoError) return PropagateStatus(aImpl->status_);
   auto bImpl = other.GetCsgLeafNode().GetImpl();
+  if (bImpl->status_ != Error::NoError) return PropagateStatus(bImpl->status_);
   return aImpl->Minkowski(*bImpl, false);
 }
 
@@ -936,7 +946,9 @@ Manifold Manifold::MinkowskiSum(const Manifold& other) const {
  */
 Manifold Manifold::MinkowskiDifference(const Manifold& other) const {
   auto aImpl = GetCsgLeafNode().GetImpl();
+  if (aImpl->status_ != Error::NoError) return PropagateStatus(aImpl->status_);
   auto bImpl = other.GetCsgLeafNode().GetImpl();
+  if (bImpl->status_ != Error::NoError) return PropagateStatus(bImpl->status_);
   return aImpl->Minkowski(*bImpl, true);
 }
 

test/manifold_test.cpp

@@ -283,6 +283,44 @@ TEST(Manifold, ErrorPropagationWarp) {
             Manifold::Error::NonFiniteVertex);
 }
 
+TEST(Manifold, ErrorPropagationMinkowski) {
+  MeshGL in = TetGL();
+  in.vertProperties[2 * 3 + 1] = NAN;
+  Manifold errored(in);
+  ASSERT_EQ(errored.Status(), Manifold::Error::NonFiniteVertex);
+  Manifold good = Manifold::Cube();
+  EXPECT_EQ(errored.MinkowskiSum(good).Status(),
+            Manifold::Error::NonFiniteVertex);
+  EXPECT_EQ(good.MinkowskiSum(errored).Status(),
+            Manifold::Error::NonFiniteVertex);
+  EXPECT_EQ(errored.MinkowskiDifference(good).Status(),
+            Manifold::Error::NonFiniteVertex);
+  EXPECT_EQ(good.MinkowskiDifference(errored).Status(),
+            Manifold::Error::NonFiniteVertex);
+}
+
+TEST(Manifold, ErrorPropagationSplitByPlane) {
+  MeshGL in = TetGL();
+  in.vertProperties[2 * 3 + 1] = NAN;
+  Manifold errored(in);
+  ASSERT_EQ(errored.Status(), Manifold::Error::NonFiniteVertex);
+  auto parts = errored.SplitByPlane(vec3(0, 0, 1), 0);
+  EXPECT_EQ(parts.first.Status(), Manifold::Error::NonFiniteVertex);
+  EXPECT_EQ(parts.second.Status(), Manifold::Error::NonFiniteVertex);
+}
+
+TEST(Manifold, ErrorPropagationMirror) {
+  MeshGL in = TetGL();
+  in.vertProperties[2 * 3 + 1] = NAN;
+  Manifold errored(in);
+  ASSERT_EQ(errored.Status(), Manifold::Error::NonFiniteVertex);
+  EXPECT_EQ(errored.Mirror(vec3(1, 0, 0)).Status(),
+            Manifold::Error::NonFiniteVertex);
+  // Degenerate normal (zero vector) on errored input should still propagate.
+  EXPECT_EQ(errored.Mirror(vec3(0, 0, 0)).Status(),
+            Manifold::Error::NonFiniteVertex);
+}
+
 TEST(Manifold, ErrorPropagationSimplify) {
   MeshGL in = TetGL();
   in.vertProperties[2 * 3 + 1] = NAN;