From 07bda56fa097f345b6b855b20861f7013de156d2 Mon Sep 17 00:00:00 2001
From: Vladimir Agafonkin <agafonkin@gmail.com>
Date: Wed, 19 Aug 2020 16:58:31 +0300
Subject: [PATCH 1/2] update attribution on layer visibility changes

---
 src/style/style.js                    | 13 ++++++++++++-
 src/ui/control/attribution_control.js |  2 +-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/style/style.js b/src/style/style.js
index 9e2c5935139..70523941871 100644
--- a/src/style/style.js
+++ b/src/style/style.js
@@ -412,8 +412,12 @@ class Style extends Evented {
             this._resetUpdates();
         }
 
+        const sourcesUsedBefore = {};
+
         for (const sourceId in this.sourceCaches) {
-            this.sourceCaches[sourceId].used = false;
+            const sourceCache = this.sourceCaches[sourceId];
+            sourcesUsedBefore[sourceId] = sourceCache.used;
+            sourceCache.used = false;
         }
 
         for (const layerId of this._order) {
@@ -425,6 +429,13 @@ class Style extends Evented {
             }
         }
 
+        for (const sourceId in sourcesUsedBefore) {
+            const sourceCache = this.sourceCaches[sourceId];
+            if (sourcesUsedBefore[sourceId] !== sourceCache.used) {
+                sourceCache.fire(new Event('data', {sourceDataType: 'visibility', dataType:'source', sourceId}));
+            }
+        }
+
         this.light.recalculate(parameters);
         this.z = parameters.zoom;
 
diff --git a/src/ui/control/attribution_control.js b/src/ui/control/attribution_control.js
index a1664f7da2b..b057efde359 100644
--- a/src/ui/control/attribution_control.js
+++ b/src/ui/control/attribution_control.js
@@ -111,7 +111,7 @@ class AttributionControl {
     }
 
     _updateData(e: any) {
-        if (e && (e.sourceDataType === 'metadata' || e.dataType === 'style')) {
+        if (e && (e.sourceDataType === 'metadata' || e.sourceDataType === 'visibility' || e.dataType === 'style')) {
             this._updateAttributions();
             this._updateEditLink();
         }

From abd33a4896adfb32d781737fef48e403a1f2159e Mon Sep 17 00:00:00 2001
From: Vladimir Agafonkin <agafonkin@gmail.com>
Date: Mon, 31 Aug 2020 11:18:23 +0300
Subject: [PATCH 2/2] add a test for attribution updating on zoom

---
 src/ui/events.js                         |  2 +-
 test/unit/ui/control/attribution.test.js | 24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/ui/events.js b/src/ui/events.js
index 229818c612a..275225d61e5 100644
--- a/src/ui/events.js
+++ b/src/ui/events.js
@@ -264,7 +264,7 @@ export type MapBoxZoomEvent = {
  * @property {boolean} [isSourceLoaded] True if the event has a `dataType` of `source` and the source has no outstanding network requests.
  * @property {Object} [source] The [style spec representation of the source](https://www.mapbox.com/mapbox-gl-style-spec/#sources) if the event has a `dataType` of `source`.
  * @property {string} [sourceDataType] Included if the event has a `dataType` of `source` and the event signals
- * that internal data has been received or changed. Possible values are `metadata` and `content`.
+ * that internal data has been received or changed. Possible values are `metadata`, `content` and `visibility`.
  * @property {Object} [tile] The tile being loaded or changed, if the event has a `dataType` of `source` and
  * the event is related to loading of a tile.
  * @property {Coordinate} [coord] The coordinate of the tile if the event has a `dataType` of `source` and
diff --git a/test/unit/ui/control/attribution.test.js b/test/unit/ui/control/attribution.test.js
index 0508f1609e4..3256110b533 100644
--- a/test/unit/ui/control/attribution.test.js
+++ b/test/unit/ui/control/attribution.test.js
@@ -239,3 +239,27 @@ test('AttributionControl hides attributions for sources that are not currently v
         }
     });
 });
+
+test('AttributionControl toggles attributions for sources whose visibility changes when zooming', (t) => {
+    const map = createMap(t);
+    const attribution = new AttributionControl();
+    map.addControl(attribution);
+
+    map.on('load', () => {
+        map.addSource('1', {type: 'geojson', data: {type: 'FeatureCollection', features: []}, attribution: 'Used'});
+        map.addLayer({id: '1', type: 'fill', source: '1', minzoom: 12});
+    });
+
+    map.on('data', (e) => {
+        if (e.dataType === 'source' && e.sourceDataType === 'metadata') {
+            t.equal(attribution._innerContainer.innerHTML, '');
+            map.setZoom(13);
+        }
+        if (e.dataType === 'source' && e.sourceDataType === 'visibility') {
+            if (map.getZoom() === 13) {
+                t.equal(attribution._innerContainer.innerHTML, 'Used');
+                t.end();
+            }
+        }
+    });
+});