From 3f08a2893e754a4f6577a8a9208097ffff2e826f Mon Sep 17 00:00:00 2001
From: Karim Naaji <karim.naaji@gmail.com>
Date: Thu, 9 Apr 2020 07:47:02 -0700
Subject: [PATCH] Fix for issue 9518 (#9520)

* Add regression test for https://github.com/mapbox/mapbox-gl-js/issues/9518

* More thorough input checks for isPatternMissing function
Fixes regression introduced by https://github.com/mapbox/mapbox-gl-js/pull/9380

ResolvedImage.fromString may now return null, which potentially leaves CrossFaded<ResolvedImage>
with missing image patterns

I have traced other code paths using ResolvedImage.fromString and have not seen
any other potential offenders
---
 src/render/painter.js                         |   1 +
 .../mapbox-gl-js#9518/expected.png            | Bin 0 -> 69 bytes
 .../regressions/mapbox-gl-js#9518/style.json  |  27 ++++++++++++++++++
 3 files changed, 28 insertions(+)
 create mode 100644 test/integration/render-tests/regressions/mapbox-gl-js#9518/expected.png
 create mode 100644 test/integration/render-tests/regressions/mapbox-gl-js#9518/style.json

diff --git a/src/render/painter.js b/src/render/painter.js
index 32fbe08548b..165a1e6e91c 100644
--- a/src/render/painter.js
+++ b/src/render/painter.js
@@ -589,6 +589,7 @@ class Painter {
      */
     isPatternMissing(image: ?CrossFaded<ResolvedImage>): boolean {
         if (!image) return false;
+        if (!image.from || !image.to) return true;
         const imagePosA = this.imageManager.getPattern(image.from.toString());
         const imagePosB = this.imageManager.getPattern(image.to.toString());
         return !imagePosA || !imagePosB;
diff --git a/test/integration/render-tests/regressions/mapbox-gl-js#9518/expected.png b/test/integration/render-tests/regressions/mapbox-gl-js#9518/expected.png
new file mode 100644
index 0000000000000000000000000000000000000000..1ed60094c40c52c61d4fb681d534520df195e0af
GIT binary patch
literal 69
zcmeAS@N?(olHy`uVBq!ia0vp^93afW1|*O0@9PFqJf1F&Ar*|t608Xf42&EMjBQR=
QMS<cBp00i_>zopr0CnFCO#lD@

literal 0
HcmV?d00001

diff --git a/test/integration/render-tests/regressions/mapbox-gl-js#9518/style.json b/test/integration/render-tests/regressions/mapbox-gl-js#9518/style.json
new file mode 100644
index 00000000000..a7d66de5770
--- /dev/null
+++ b/test/integration/render-tests/regressions/mapbox-gl-js#9518/style.json
@@ -0,0 +1,27 @@
+{
+  "version": 8,
+  "metadata": {
+    "test": {
+      "width": 8,
+      "height": 8
+    }
+  },
+  "zoom": 3,
+  "sources": {},
+  "sprite": "local://sprites/emerald",
+  "layers": [
+    {
+      "id": "background",
+      "type": "background",
+      "paint": {
+        "background-pattern": [
+          "step",
+          ["zoom"],
+          "",
+          5,
+          "cemetery_icon"
+        ]
+      }
+    }
+  ]
+}