From b0ba8bded514e791ba8bd7eda4a513a762c5e5ae Mon Sep 17 00:00:00 2001
From: Ansis Brammanis <ansis@mapbox.com>
Date: Thu, 19 Apr 2018 13:08:03 -0400
Subject: [PATCH] fix #6501, fix moving layer to it's current location

---
 src/style/style.js            |  4 ++++
 test/unit/style/style.test.js | 17 +++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/style/style.js b/src/style/style.js
index e34f9d6995a..a8dbde5ab9c 100644
--- a/src/style/style.js
+++ b/src/style/style.js
@@ -605,6 +605,10 @@ class Style extends Evented {
             return;
         }
 
+        if (id === before) {
+            return;
+        }
+
         const index = this._order.indexOf(id);
         this._order.splice(index, 1);
 
diff --git a/test/unit/style/style.test.js b/test/unit/style/style.test.js
index d101aeaafbf..1f3c2e65fcc 100644
--- a/test/unit/style/style.test.js
+++ b/test/unit/style/style.test.js
@@ -1273,6 +1273,23 @@ test('Style#moveLayer', (t) => {
         });
     });
 
+    t.test('moves to existing location', (t) => {
+        const style = new Style(new StubMap());
+        style.loadJSON(createStyleJSON({
+            layers: [
+                {id: 'a', type: 'background'},
+                {id: 'b', type: 'background'},
+                {id: 'c', type: 'background'}
+            ]
+        }));
+
+        style.on('style.load', () => {
+            style.moveLayer('b', 'b');
+            t.deepEqual(style._order, ['a', 'b', 'c']);
+            t.end();
+        });
+    });
+
     t.end();
 });