Setting a property to null in collections removes property

Author: nyalldawson

python/core/qgsproperty.sip

@@ -630,7 +630,8 @@ class QgsPropertyCollection
      * @param key integer key for property. Any existing property with the same key will be deleted
      * and replaced by this property. The intended use case is that a context specific enum is cast to
      * int and used for the key value.
-     * @param property property to add. Ownership is transferred to the collection.
+     * @param property property to add. Ownership is transferred to the collection. Setting a property
+     * to null will remove the property from the collection.
      */
     void setProperty( int key, QgsAbstractProperty* property /Transfer/ );
 

src/core/qgsproperty.cpp

@@ -724,7 +724,9 @@ void QgsPropertyCollection::setProperty( int key, QgsAbstractProperty* property
   if ( hasProperty( key ) )
     delete mProperties.take( key );
 
-  mProperties.insert( key, property );
+  if ( property )
+    mProperties.insert( key, property );
+
   mDirty = true;
 }
 

src/core/qgsproperty.h

@@ -718,7 +718,8 @@ class CORE_EXPORT QgsPropertyCollection
      * @param key integer key for property. Any existing property with the same key will be deleted
      * and replaced by this property. The intended use case is that a context specific enum is cast to
      * int and used for the key value.
-     * @param property property to add. Ownership is transferred to the collection.
+     * @param property property to add. Ownership is transferred to the collection. Setting a property
+     * to null will remove the property from the collection.
      */
     void setProperty( int key, QgsAbstractProperty* property );
 

tests/src/core/testqgsproperty.cpp

@@ -797,6 +797,12 @@ void TestQgsProperty::propertyCollection()
   QCOMPARE( collection.count(), 2 );
   QCOMPARE( collection.propertyKeys().toSet(), QSet<int>() << Property1 << Property3 );
 
+  //test removing a property
+  collection.setProperty( Property1, nullptr );
+  QVERIFY( !collection.property( Property1 ) );
+  QVERIFY( !collection.hasProperty( Property1 ) );
+  QCOMPARE( collection.propertyKeys(), QList<int>() << Property3 );
+
   //clear
   collection.clear();
   QCOMPARE( collection.count(), 0 );