[core] Synchronize state of CollisionIndex and FeatureIndexes.

Fixes issue #10778, in which mismatch between FeatureIndex and CollisionIndex could lead to inconsistent results or even invalid array access.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/mbgl/tile/tile.hpp b/src/mbgl/tile/tile.hpp
index b7e200266f..1bed180f3d 100644
--- a/src/mbgl/tile/tile.hpp
+++ b/src/mbgl/tile/tile.hpp
@@ -109,6 +109,11 @@ public:
     // and will have time to finish by the second placement.
     virtual void performedFadePlacement() {}
     
+    // FeatureIndexes are loaded asynchronously, but must be used with a CollisionIndex
+    // generated from the same data. Calling commitFeatureIndex signals the current
+    // CollisionIndex is up-to-date and allows us to start using the last loaded FeatureIndex
+    virtual void commitFeatureIndex() {}
+    
     void dumpDebugLogs() const;
 
     const OverscaledTileID id;