1 files changed, 27 insertions, 0 deletions
diff --git a/src/mbgl/style/layers/symbol_layer_impl.cpp b/src/mbgl/style/layers/symbol_layer_impl.cpp
index 753b2fa184..e177391686 100644
--- a/src/mbgl/style/layers/symbol_layer_impl.cpp
+++ b/src/mbgl/style/layers/symbol_layer_impl.cpp
@@ -1,5 +1,7 @@
 #include <mbgl/style/layers/symbol_layer_impl.hpp>
 
+#include <mbgl/util/logging.hpp>
+
 namespace mbgl {
 namespace style {
 
@@ -12,5 +14,30 @@ bool SymbolLayer::Impl::hasLayoutDifference(const Layer::Impl& other) const {
            paint.hasDataDrivenPropertyDifference(impl.paint);
 }
 
+void SymbolLayer::Impl::populateFontStack(std::set<FontStack>& fontStack) const {
+    if (layout.get<TextField>().isUndefined()) {
+        return;
+    }
+
+    layout.get<TextFont>().match(
+        [&] (Undefined) {
+            fontStack.insert({"Open Sans Regular", "Arial Unicode MS Regular"});
+        },
+        [&] (const FontStack& constant) {
+            fontStack.insert(constant);
+        },
+        [&] (const auto& function) {
+            for (const auto& value : function.possibleOutputs()) {
+                if (value) {
+                    fontStack.insert(*value);
+                } else {
+                    Log::Warning(Event::ParseStyle, "Layer '%s' has an invalid value for text-font and will not render text. Output values must be contained as literals within the expression.", id.c_str());
+                    break;
+                }
+            }
+        }
+    );
+}
+
 } // namespace style
 } // namespace mbgl