Accept constant expressions in non-dds properties

cmake/test-files.cmake

@@ -79,6 +79,7 @@ set(MBGL_TEST_FILES
  test/style/conversion/geojson_options.test.cpp
  test/style/conversion/layer.test.cpp
  test/style/conversion/light.test.cpp
+ test/style/conversion/property_value.test.cpp
  test/style/conversion/stringify.test.cpp
  test/style/conversion/tileset.test.cpp
 

include/mbgl/style/conversion/property_value.hpp

@@ -29,11 +29,19 @@ struct Converter<PropertyValue<T>> {
  return {};
  }
 
- if (isFeatureConstant(**expression)) {
- return { CameraFunction<T>(std::move(*expression)) };
- } else {
+ if (!isFeatureConstant(**expression)) {
  error = { "property expressions not supported" };
  return {};
+ } else if (!isZoomConstant(**expression)) {
+ return { CameraFunction<T>(std::move(*expression)) };
+ } else {
+ auto literal = dynamic_cast<Literal*>(expression->get());
+ assert(literal);
+ optional<T> constant = fromExpressionValue<T>(literal->getValue());
+ if (!constant) {
+ return {};
+ }
+ return PropertyValue<T>(*constant);
  }
  } else if (isObject(value)) {
  optional<CameraFunction<T>> function = convert<CameraFunction<T>>(value, error);

test/style/conversion/property_value.test.cpp

@@ -0,0 +1,21 @@
+#include <mbgl/test/util.hpp>
+
+#include <mbgl/style/conversion/json.hpp>
+#include <mbgl/style/conversion/property_value.hpp>
+#include <mbgl/util/rapidjson.hpp>
+
+using namespace mbgl;
+using namespace mbgl::style;
+using namespace mbgl::style::conversion;
+
+TEST(StyleConversion, PropertyValue) {
+ // PropertyValue<T> accepts a constant expression: https://github.com/mapbox/mapbox-gl-native/issues/11940
+ Error error;
+ JSDocument doc;
+ doc.Parse<0>(R"(["literal", [1, 2]])");
+ auto expected = std::array<float, 2>{{1, 2}};
+ auto result = convert<PropertyValue<std::array<float, 2>>>(doc, error);
+ ASSERT_TRUE(result);
+ ASSERT_TRUE(result->isConstant());
+ ASSERT_EQ(result->asConstant(), expected);
+}