[core] use stale sprite data

This is a naïve implementation that essentially merges updated data into existing data. It will *not* remove icons from the stale sprite if they aren't present in the fresh sprite (we aren't tracking the source of a sprite, and the user could have changed it as well). Similarly, it will not update icons that have changed in dimension. This is a rare edge case and probably not worth implementing.

4 files changed, 36 insertions, 0 deletions

diff --git a/test/fixtures/stale/sprite.json b/test/fixtures/stale/sprite.json
new file mode 100644
index 0000000000..e640365519
--- /dev/null
+++ b/test/fixtures/stale/sprite.json
@@ -0,0 +1,10 @@
+{
+  "noise": {
+    "x": 0,
+    "y": 0,
+    "width": 32,
+    "height": 32,
+    "pixelRatio": 1,
+    "sdf": false
+  }
+}
diff --git a/test/fixtures/stale/sprite.png b/test/fixtures/stale/sprite.png
new file mode 100644
index 0000000000..a02d8eb542
--- /dev/null
+++ b/test/fixtures/stale/sprite.png
diff --git a/test/fixtures/stale/stale_style_and_sprite/expected.png b/test/fixtures/stale/stale_style_and_sprite/expected.png
new file mode 100644
index 0000000000..171599bf5c
--- /dev/null
+++ b/test/fixtures/stale/stale_style_and_sprite/expected.png
diff --git a/test/fixtures/stale/style_and_sprite.json b/test/fixtures/stale/style_and_sprite.json
new file mode 100644
index 0000000000..61e3214a5e
--- /dev/null
+++ b/test/fixtures/stale/style_and_sprite.json
@@ -0,0 +1,26 @@
+{
+  "version": 8,
+  "name": "Water",
+  "sources": {
+    "mapbox": {
+      "type": "vector",
+      "url": "asset://test/fixtures/stale/streets.json"
+    }
+  },
+  "sprite": "http://127.0.0.1:3000/stale/sprite",
+  "layers": [{
+    "id": "background",
+    "type": "background",
+    "paint": {
+      "background-color": "red"
+    }
+  }, {
+    "id": "water",
+    "type": "fill",
+    "source": "mapbox",
+    "source-layer": "water",
+    "paint": {
+      "fill-pattern": "noise"
+    }
+  }]
+}