From a1dca3c32e5438856b68dad07fa81c8332807a81 Mon Sep 17 00:00:00 2001
From: John Firebaugh <john.firebaugh@gmail.com>
Date: Wed, 12 Sep 2018 10:32:01 -0700
Subject: [PATCH] Make "to-number" of null behave as documented

---
 src/style-spec/expression/definitions/coercion.js           | 2 +-
 test/integration/expression-tests/to-number/2-ary/test.json | 6 +++---
 test/integration/expression-tests/to-number/basic/test.json | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/style-spec/expression/definitions/coercion.js b/src/style-spec/expression/definitions/coercion.js
index d459a5da6fc..e48ea2192b4 100644
--- a/src/style-spec/expression/definitions/coercion.js
+++ b/src/style-spec/expression/definitions/coercion.js
@@ -90,7 +90,7 @@ class Coercion implements Expression {
             let value = null;
             for (const arg of this.args) {
                 value = arg.evaluate(ctx);
-                if (value === null) continue;
+                if (value === null) return 0;
                 const num = Number(value);
                 if (isNaN(num)) continue;
                 return num;
diff --git a/test/integration/expression-tests/to-number/2-ary/test.json b/test/integration/expression-tests/to-number/2-ary/test.json
index 9806be5a092..bbed5b9cbab 100644
--- a/test/integration/expression-tests/to-number/2-ary/test.json
+++ b/test/integration/expression-tests/to-number/2-ary/test.json
@@ -23,11 +23,11 @@
       1,
       6.02e-23,
       -1,
+      0,
       -1,
       -1,
-      -1,
-      -1,
-      {"error": "Could not convert \"bad fallback\" to number."}
+      0,
+      0
     ],
     "serialized": ["to-number", ["get", "x"], ["get", "y"]]
   }
diff --git a/test/integration/expression-tests/to-number/basic/test.json b/test/integration/expression-tests/to-number/basic/test.json
index b0c13c11805..1d769c89f0d 100644
--- a/test/integration/expression-tests/to-number/basic/test.json
+++ b/test/integration/expression-tests/to-number/basic/test.json
@@ -21,7 +21,7 @@
       1,
       6.02e-23,
       {"error": "Could not convert \"Not a number\" to number."},
-      {"error": "Could not convert null to number."},
+      0,
       {"error": "Could not convert [1,2] to number."},
       {"error": "Could not convert {\"y\":1} to number."}
     ],