4 files changed, 82 insertions, 5 deletions

diff --git a/src/mbgl/map/source.cpp b/src/mbgl/map/source.cpp
index ed57ddce0b..4432b3a490 100644
--- a/src/mbgl/map/source.cpp
+++ b/src/mbgl/map/source.cpp
@@ -90,14 +90,13 @@ void Source::load() {
     // URL may either be a TileJSON file, or a GeoJSON file.
     FileSource* fs = util::ThreadContext::getFileSource();
     req = fs->request({ Resource::Kind::Source, url }, [this](Response res) {
-        if (res.stale) {
-            // Only handle fresh responses.
+        if (res.error) {
+            observer->onSourceError(*this, std::make_exception_ptr(std::runtime_error(res.error->message)));
             return;
         }
-        req = nullptr;
 
-        if (res.error) {
-            observer->onSourceError(*this, std::make_exception_ptr(std::runtime_error(res.error->message)));
+        if (res.notModified) {
+            // We got the same data back as last time. Abort early.
             return;
         }
 
@@ -111,6 +110,7 @@ void Source::load() {
             return;
         }
 
+        bool reloadTiles = false;
         if (type == SourceType::Vector || type == SourceType::Raster) {
             // Create a new copy of the SourceInfo object that holds the base values we've parsed
             // from the stylesheet. Then merge in the values parsed from the TileJSON we retrieved
@@ -124,10 +124,39 @@ void Source::load() {
                 std::transform(newInfo->tiles.begin(), newInfo->tiles.end(), newInfo->tiles.begin(),
                                util::mapbox::normalizeRasterTileURL);
             }
+
+            // Check whether previous information specifies different tile
+            if (info && info->tiles != newInfo->tiles) {
+                reloadTiles = true;
+
+                // Tile size changed: We need to recalculate the tiles we need to load because we
+                // might have to load tiles for a different zoom level
+                // This is done automatically when we trigger the onSourceLoaded observer below.
+
+                // Min/Max zoom changed: We need to recalculate what tiles to load, if we have tiles
+                // loaded that are outside the new zoom range
+                // This is done automatically when we trigger the onSourceLoaded observer below.
+
+                // Attribution changed: We need to notify the embedding application that this
+                // changed. See https://github.com/mapbox/mapbox-gl-native/issues/2723
+                // This is not yet implemented.
+
+                // Center/bounds changed: We're not using these values currently
+            }
+
             info = std::move(newInfo);
         } else if (type == SourceType::GeoJSON) {
             info = std::make_unique<SourceInfo>();
             geojsonvt = StyleParser::parseGeoJSON(d);
+            reloadTiles = true;
+        }
+
+        if (reloadTiles) {
+            // Tile information changed because we got new GeoJSON data, or a new tile URL.
+            tilePtrs.clear();
+            tileDataMap.clear();
+            tiles.clear();
+            cache.clear();
         }
 
         loaded = true;
diff --git a/test/fixtures/stale/stale_style_and_tilejson/expected.png b/test/fixtures/stale/stale_style_and_tilejson/expected.png
new file mode 100644
index 0000000000..d3c6ef3cd5
--- /dev/null
+++ b/test/fixtures/stale/stale_style_and_tilejson/expected.png
diff --git a/test/fixtures/stale/style_and_tilejson.json b/test/fixtures/stale/style_and_tilejson.json
new file mode 100644
index 0000000000..f2a4fddd0b
--- /dev/null
+++ b/test/fixtures/stale/style_and_tilejson.json
@@ -0,0 +1,25 @@
+{
+  "version": 8,
+  "name": "Water",
+  "sources": {
+    "mapbox": {
+      "type": "vector",
+      "url": "http://127.0.0.1:3000/stale/streets.json"
+    }
+  },
+  "layers": [{
+    "id": "background",
+    "type": "background",
+    "paint": {
+      "background-color": "red"
+    }
+  }, {
+    "id": "water",
+    "type": "fill",
+    "source": "mapbox",
+    "source-layer": "water",
+    "paint": {
+      "fill-color": "blue"
+    }
+  }]
+}
diff --git a/test/storage/cache_stale.cpp b/test/storage/cache_stale.cpp
index cc421f7c34..7f379b78a2 100644
--- a/test/storage/cache_stale.cpp
+++ b/test/storage/cache_stale.cpp
@@ -49,3 +49,26 @@ TEST_F(Storage, CacheStaleStyle) {
 
     checkRendering(map, "stale_style", 1000ms);
 }
+
+TEST_F(Storage, CacheStaleStyleAndTileJSON) {
+    HeadlessView view(display, 1);
+
+    auto cache = SQLiteCache::getShared(":memory:");
+
+    // Rig the cache with an expired stylesheet.
+    const std::string stylePath = "stale/style_and_tilejson.json";
+    const Resource styleResource{ Resource::Kind::Style, prefix + "/" + stylePath };
+    cache->put(styleResource, expiredItem(stylePath));
+
+    // Rig the cache with an expired TileJSON.
+    const std::string tilejsonPath = "stale/streets.json";
+    const Resource tilejsonResource{ Resource::Kind::Source, prefix + "/" + tilejsonPath };
+    cache->put(tilejsonResource, expiredItem(tilejsonPath));
+
+    DefaultFileSource fileSource(":memory:", ".");
+
+    Map map(view, fileSource, MapMode::Still);
+    map.setStyleURL(styleResource.url);
+
+    checkRendering(map, "stale_style_and_tilejson", 1000ms);
+}