[core] use stale glyphs

Updating glyphs is still unsupported, and there's no good use case for doing so. When we're using a stale glyph PBF, and the fresh answer contains changed to that glyph, we will continue to use the old glyph.

5 files changed, 70 insertions, 6 deletions

diff --git a/test/fixtures/stale/glyph.pbf b/test/fixtures/stale/glyph.pbf
new file mode 100644
index 0000000000..0d160f7898
--- /dev/null
+++ b/test/fixtures/stale/glyph.pbf
diff --git a/test/fixtures/stale/stale_style_and_glyphs/expected.png b/test/fixtures/stale/stale_style_and_glyphs/expected.png
new file mode 100644
index 0000000000..d8dbda1092
--- /dev/null
+++ b/test/fixtures/stale/stale_style_and_glyphs/expected.png
diff --git a/test/fixtures/stale/style_and_glyphs.json b/test/fixtures/stale/style_and_glyphs.json
new file mode 100644
index 0000000000..adf91705fb
--- /dev/null
+++ b/test/fixtures/stale/style_and_glyphs.json
@@ -0,0 +1,39 @@
+{
+  "version": 8,
+  "name": "Water",
+  "sources": {
+    "mapbox": {
+      "type": "vector",
+      "url": "asset://test/fixtures/stale/streets.json"
+    }
+  },
+  "glyphs": "http://127.0.0.1:3000/stale/{fontstack}/{range}.pbf",
+  "layers": [{
+    "id": "background",
+    "type": "background",
+    "paint": {
+      "background-color": "red"
+    }
+  }, {
+    "id": "water",
+    "type": "fill",
+    "source": "mapbox",
+    "source-layer": "water",
+    "paint": {
+      "fill-color": "blue"
+    }
+  }, {
+    "id": "admin",
+    "type": "symbol",
+    "source": "mapbox",
+    "source-layer": "admin",
+    "layout": {
+        "text-field": "Text"
+    },
+    "paint": {
+      "text-color": "black",
+      "text-halo-color": "white",
+      "text-halo-width": 2
+    }
+  }]
+}
diff --git a/test/storage/cache_stale.cpp b/test/storage/cache_stale.cpp
index ab9fe7b202..96fd9bbbcd 100644
--- a/test/storage/cache_stale.cpp
+++ b/test/storage/cache_stale.cpp
@@ -15,8 +15,13 @@ using namespace std::literals::string_literals;
 
 namespace {
 
-void checkRendering(Map& map, const char *name, std::chrono::milliseconds timeout) {
-    test::checkImage("test/fixtures/stale/"s + name, test::render(map, timeout), 0.001, 0.1);
+void checkRendering(Map& map,
+                    const char* name,
+                    std::chrono::milliseconds timeout,
+                    double imageThreshold = 0.001,
+                    double pixelThreshold = 0.1) {
+    test::checkImage("test/fixtures/stale/"s + name, test::render(map, timeout), imageThreshold,
+                     pixelThreshold);
 }
 
 Response expiredItem(const std::string& path) {
@@ -100,3 +105,27 @@ TEST_F(Storage, CacheStaleStyleAndSprite) {
 
     checkRendering(map, "stale_style_and_sprite", 1000ms);
 }
+
+TEST_F(Storage, CacheStaleStyleAndGlyphs) {
+    HeadlessView view(display, 1);
+
+    auto cache = SQLiteCache::getShared(":memory:");
+
+    // Rig the cache with an expired stylesheet.
+    const std::string stylePath = "stale/style_and_glyphs.json";
+    const Resource styleResource{ Resource::Kind::Style, prefix + "/" + stylePath };
+    cache->put(styleResource, expiredItem(stylePath));
+
+    // Rig the cache with an expired glyph PBF.
+    const std::string glyphPath = "stale/glyph.pbf";
+    const Resource glyphResource{ Resource::Kind::Glyphs, prefix + "/stale/Open%20Sans%20Regular%2c%20Arial%20Unicode%20MS%20Regular/0-255.pbf" };
+    cache->put(glyphResource, expiredItem(glyphPath));
+
+    DefaultFileSource fileSource(":memory:", ".");
+
+    Map map(view, fileSource, MapMode::Still);
+    map.setStyleURL(styleResource.url);
+
+    // TODO: this shouldn't take > 1 second
+    checkRendering(map, "stale_style_and_glyphs", 2000ms, 0.0015);
+}
diff --git a/test/style/glyph_store.cpp b/test/style/glyph_store.cpp
index a53b20c6d2..0215dff3ff 100644
--- a/test/style/glyph_store.cpp
+++ b/test/style/glyph_store.cpp
@@ -52,7 +52,6 @@ TEST(GlyphStore, LoadingSuccess) {
             return;
 
         auto fontStack = test.glyphStore.getFontStack("Test Stack");
-        ASSERT_FALSE(fontStack->getMetrics().empty());
         ASSERT_FALSE(fontStack->getSDFs().empty());
 
         test.end();
@@ -73,7 +72,6 @@ TEST(GlyphStore, LoadingFail) {
         ASSERT_EQ(glyphRange, GlyphRange(0, 255));
 
         auto stack = test.glyphStore.getFontStack("Test Stack");
-        ASSERT_TRUE(stack->getMetrics().empty());
         ASSERT_TRUE(stack->getSDFs().empty());
         ASSERT_FALSE(test.glyphStore.hasGlyphRanges("Test Stack", {{0, 255}}));
 
@@ -95,7 +93,6 @@ TEST(GlyphStore, LoadingCorrupted) {
         ASSERT_EQ(glyphRange, GlyphRange(0, 255));
 
         auto stack = test.glyphStore.getFontStack("Test Stack");
-        ASSERT_TRUE(stack->getMetrics().empty());
         ASSERT_TRUE(stack->getSDFs().empty());
         ASSERT_FALSE(test.glyphStore.hasGlyphRanges("Test Stack", {{0, 255}}));
 
@@ -132,7 +129,6 @@ TEST(GlyphStore, InvalidURL) {
         ASSERT_TRUE(error != nullptr);
 
         auto stack = test.glyphStore.getFontStack("Test Stack");
-        ASSERT_TRUE(stack->getMetrics().empty());
         ASSERT_TRUE(stack->getSDFs().empty());
 
         test.end();