Fix merging of composite availability

CHANGES.md

@@ -8,6 +8,7 @@ Change Log
 
 ##### Fixes :wrench:
 * Fixed an error where `clampToHeightMostDetailed` or `sampleHeightMostDetailed` would crash if entities were created when the promise resolved. [#7690](https://github.com/AnalyticalGraphicsInc/cesium/pull/7690)
+* Fixed an issue with compositing merged entity availability. [#7717](https://github.com/AnalyticalGraphicsInc/cesium/issues/7717)
 * Fixed an error where many imagery layers within a single tile would cause parts of the tile to render as black on some platforms. [#7649](https://github.com/AnalyticalGraphicsInc/cesium/issues/7649)
 
 ### 1.56.1 - 2019-04-02

Source/DataSources/CompositeEntityCollection.js

@@ -27,6 +27,8 @@ define([
         for (var i = 0; i < propertyNamesLength; i++) {
             entity[propertyNames[i]] = undefined;
         }
+        entity._name = undefined;
+        entity._availability = undefined;
     }
 
     function subscribeToEntity(that, eventHash, collectionId, entity) {

Source/DataSources/Entity.js

@@ -566,7 +566,7 @@ define([
         //Name, show, and availability are not Property objects and are currently handled differently.
         //source.show is intentionally ignored because this.show always has a value.
         this.name = defaultValue(this.name, source.name);
-        this.availability = defaultValue(source.availability, this.availability);
+        this.availability = defaultValue(this.availability, source.availability);
 
         var propertyNames = this._propertyNames;
         var sourcePropertyNames = defined(source._propertyNames) ? source._propertyNames : Object.keys(source);

Specs/DataSources/CompositeEntityCollectionSpec.js

@@ -536,6 +536,57 @@ defineSuite([
         expect(compositeObject.billboard.show).toBeUndefined();
     });
 
+    it('per-entity availability works', function() {
+        var id = 'test';
+        var collection1 = new EntityCollection();
+        var availability1 = new TimeIntervalCollection();
+        availability1.addInterval(TimeInterval.fromIso8601({
+            iso8601 : '2019-01-01/2019-01-04'
+        }));
+        var entity1 = new Entity({
+            id : id,
+            availability : availability1
+        });
+        collection1.add(entity1);
+
+        var collection2 = new EntityCollection();
+        var availability2 = new TimeIntervalCollection();
+        availability2.addInterval(TimeInterval.fromIso8601({
+            iso8601 : '2019-01-02/2019-01-05'
+        }));
+        var entity2 = new Entity({
+            id : id,
+            availability : availability2
+        });
+        collection2.add(entity2);
+
+        var collection3 = new EntityCollection();
+        var availability3 = new TimeIntervalCollection();
+        availability3.addInterval(TimeInterval.fromIso8601({
+            iso8601 : '2019-01-03/2019-01-06'
+        }));
+        var entity3 = new Entity({
+            id : id,
+            availability : availability3
+        });
+        collection3.add(entity3);
+
+        //Add collections in reverse order to lower numbers of priority
+        var composite = new CompositeEntityCollection();
+        composite.addCollection(collection3);
+        composite.addCollection(collection2);
+        composite.addCollection(collection1);
+
+        var compositeObject = composite.getById(id);
+        expect(compositeObject.availability.start).toEqual(JulianDate.fromIso8601('2019-01-01'));
+
+        composite.removeCollection(collection1);
+        expect(compositeObject.availability.start).toEqual(JulianDate.fromIso8601('2019-01-02'));
+
+        composite.removeCollection(collection2);
+        expect(compositeObject.availability.start).toEqual(JulianDate.fromIso8601('2019-01-03'));
+    });
+
     it('works when collection being composited suspends updates', function() {
         var collection = new EntityCollection();
         var composite = new CompositeEntityCollection([collection]);

Specs/DataSources/EntitySpec.js

@@ -200,7 +200,7 @@ defineSuite([
         }
     });
 
-    it('merge always overwrites availability', function() {
+    it('merge does not overwrite availability', function() {
         var entity = new Entity();
         var interval = TimeInterval.fromIso8601({
             iso8601 : '2000-01-01/2001-01-01'
@@ -214,7 +214,7 @@ defineSuite([
         entity2.availability = interval2;
 
         entity.merge(entity2);
-        expect(entity.availability).toBe(interval2);
+        expect(entity.availability).toBe(interval);
     });
 
     it('merge works with custom properties.', function() {