do not hide icons if text is an empty string

src/data/bucket/symbol_bucket.js

@@ -65,6 +65,17 @@ export type CollisionArrays = {
     textCircles?: Array<number>;
 };
 
+export type SymbolFeature = {|
+    text: string | void,
+    icon: string | void,
+    index: number,
+    sourceLayerIndex: number,
+    geometry: Array<Array<Point>>,
+    properties: Object,
+    type: 'Point' | 'LineString' | 'Polygon',
+    id?: any
+|};
+
 export type SymbolInstance = {
     key: string,
     textBoxStartIndex: number,
@@ -76,7 +87,7 @@ export type SymbolInstance = {
     anchor: Anchor,
     line: Array<Point>,
     featureIndex: number,
-    feature: ExpressionFeature,
+    feature: SymbolFeature,
     textCollisionFeature?: {boxStartIndex: number, boxEndIndex: number},
     iconCollisionFeature?: {boxStartIndex: number, boxEndIndex: number},
     placedTextSymbolIndices: Array<number>;
@@ -92,17 +103,6 @@ export type SymbolInstance = {
     hidden?: boolean;
 };
 
-export type SymbolFeature = {|
-    text: string | void,
-    icon: string | void,
-    index: number,
-    sourceLayerIndex: number,
-    geometry: Array<Array<Point>>,
-    properties: Object,
-    type: 'Point' | 'LineString' | 'Polygon',
-    id?: any
-|};
-
 // Opacity arrays are frequently updated but don't contain a lot of information, so we pack them
 // tight. Each Uint32 is actually four duplicate Uint8s for the four corners of a glyph
 // 7 bits are for the current opacity, and the lowest bit is the target opacity

src/symbol/placement.js

@@ -118,8 +118,8 @@ class Placement {
         for (const symbolInstance of bucket.symbolInstances) {
             if (!seenCrossTileIDs[symbolInstance.crossTileID]) {
 
-                let placeText = false;
-                let placeIcon = false;
+                let placeText = symbolInstance.feature.text !== undefined;
+                let placeIcon = symbolInstance.feature.icon !== undefined;
                 let offscreen = true;
 
                 let placedGlyphBoxes = null;

test/integration/render-tests/regressions/mapbox-gl-js#6160/style.json

@@ -0,0 +1,73 @@
+{
+  "version": 8,
+  "metadata": {
+    "test": {
+      "width": 64,
+      "height": 64,
+      "description": "Checks that icons are not hidden when the text is an empty string"
+    }
+  },
+  "glyphs": "local://glyphs/{fontstack}/{range}.pbf",
+  "sources": {
+    "geojson": {
+      "type": "geojson",
+      "data": {
+        "type": "FeatureCollection",
+        "features": [
+            {
+                "type": "Feature",
+                "geometry": {
+                    "type": "Point",
+                    "coordinates": [
+                      0,
+                      0
+                    ]
+                },
+                "properties": {
+                    "text": "OK"
+                }
+            },
+            {
+                "type": "Feature",
+                "geometry": {
+                    "type": "Point",
+                    "coordinates": [
+                      20,
+                      0
+                    ]
+                },
+                "properties": {
+                    "text": ""
+                }
+            }
+        ]
+      }
+    }
+  },
+  "sprite": "local://sprites/sprite",
+  "layers": [
+    {
+      "id": "symbol",
+      "type": "symbol",
+      "source": "geojson",
+      "layout": {
+        "symbol-placement": "point",
+        "text-allow-overlap": true,
+        "icon-allow-overlap": true,
+        "icon-image": "triangle-12",
+        "text-field": "{text}",
+        "text-font": [
+          "Open Sans Semibold",
+          "Arial Unicode MS Bold"
+        ]
+      },
+      "paint": {
+        "icon-opacity": 0.5,
+        "text-translate": [
+          -10,
+          0
+        ]
+      }
+    }
+  ]
+}