Repository navigation
Documentation example code invalid for latest library version #628
Description
From https://s2geometry.io/devguide/s2shapeindex.html:
void TestContainment(const vector<S2Point>& points,
const vector<S2Polygon*>& polygons) {
MutableS2ShapeIndex index;
for (auto polygon : polygons) {
index.Add(absl::make_unique<S2Polygon::Shape>(polygon));
}
auto query = MakeS2ContainsPointQuery(&index);
for (const auto& point: points) {
for (S2Shape* shape : query.GetContainingShapes(point)) {
S2Polygon* polygon = polygons[shape->id()];
... do something with (point, polygon) ...
}
}
}
This code does not compile for several reasons:
GetContainingShapesnow returnsstd::vector<const S2Shape*>- There is no
id()function inS2Shape(removed in this commit: 84bfd2c)
Activity
rksharma-owg commentedon Oct 14, 2026
Confirmed against current master (
677c8cebcff11ba11accc0b02005bc214e06e9fd): the published example still fails becauseGetContainingShapes()yieldsconst S2Shape*, andS2Shapeno longer hasid().The existing
VisitContainingShapeIds()API supplies the IDs directly, so the inner loop can preserve the original polygon lookup:Returning
truekeeps visiting matches. This lookup assumes the fresh index is populated in the same order aspolygons, as in the example.I checked the original and corrected snippets with C++20, Apple Clang 21, and the repository-required Abseil LTS 20260526.0. The original reproduces both errors; the corrected version passes
-fsyntax-only. Existing Abseil deprecation warnings remain; this was a compile check, not a runtime or full-library test.Where is the website's developer-guide source maintained so this correction can be submitted in the right place?