[core] Fix flickering caused by regression in #7586

It should be safe to invoke GeometryTileWorker::setData multiple times without invoking GeometryTileWorker::setLayers. Therefore GeometryTileWorker::redoLayout() must not consume the layers.

1 files changed, 72 insertions, 0 deletions

diff --git a/test/tile/geojson_tile.test.cpp b/test/tile/geojson_tile.test.cpp
new file mode 100644
index 0000000000..920e946a2b
--- /dev/null
+++ b/test/tile/geojson_tile.test.cpp
@@ -0,0 +1,72 @@
+#include <mbgl/test/util.hpp>
+#include <mbgl/test/fake_file_source.hpp>
+#include <mbgl/test/stub_tile_observer.hpp>
+#include <mbgl/tile/geojson_tile.hpp>
+#include <mbgl/tile/tile_loader_impl.hpp>
+
+#include <mbgl/util/default_thread_pool.hpp>
+#include <mbgl/util/run_loop.hpp>
+#include <mbgl/map/transform.hpp>
+#include <mbgl/style/style.hpp>
+#include <mbgl/style/update_parameters.hpp>
+#include <mbgl/style/layers/circle_layer.hpp>
+#include <mbgl/annotation/annotation_manager.hpp>
+
+#include <memory>
+
+using namespace mbgl;
+using namespace mbgl::style;
+
+class GeoJSONTileTest {
+public:
+    FakeFileSource fileSource;
+    TransformState transformState;
+    util::RunLoop loop;
+    ThreadPool threadPool { 1 };
+    AnnotationManager annotationManager { 1.0 };
+    style::Style style { fileSource, 1.0 };
+    Tileset tileset { { "https://example.com" }, { 0, 22 }, "none" };
+
+    style::UpdateParameters updateParameters {
+        1.0,
+        MapDebugOptions(),
+        transformState,
+        threadPool,
+        fileSource,
+        MapMode::Continuous,
+        annotationManager,
+        style
+    };
+};
+
+TEST(GeoJSONTile, Issue7648) {
+    GeoJSONTileTest test;
+    GeoJSONTile tile(OverscaledTileID(0, 0, 0), "source", test.updateParameters);
+
+    test.style.addLayer(std::make_unique<CircleLayer>("circle", "source"));
+
+    StubTileObserver observer;
+    observer.tileChanged = [&] (const Tile&) {
+        // Once present, the bucket should never "disappear", which would cause
+        // flickering.
+        ASSERT_NE(nullptr, tile.getBucket(*test.style.getLayer("circle")));
+    };
+    tile.setObserver(&observer);
+
+    tile.setPlacementConfig({});
+
+    mapbox::geometry::feature_collection<int16_t> features;
+    features.push_back(mapbox::geometry::feature<int16_t> {
+        mapbox::geometry::point<int16_t>(0, 0)
+    });
+
+    tile.updateData(features);
+    while (!tile.isComplete()) {
+        test.loop.runOnce();
+    }
+
+    tile.updateData(features);
+    while (!tile.isComplete()) {
+        test.loop.runOnce();
+    }
+}