chore: Prepare release branch for new release

.travis.yml

@@ -23,6 +23,6 @@ cache:
 branches:
   only:
   - master
-  - /^\d+\.\d+\.\d+(-SNAPSHOT|-alpha|-beta)?\d*$/ # trigger builds on tags which are semantically versioned to ship the SDK.
+  - /^\d+\.\d+\.(\d|[x])+(-SNAPSHOT|-alpha|-beta)?\d*$/ # trigger builds on tags which are semantically versioned to ship the SDK.
 after_success:
   - ./gradlew coveralls uploadArchives --console plain

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Optimizely Java X SDK Changelog
 
+## 2.1.3
+
+September 21st, 2018
+
+### Bug Fixes
+* fix(attributes): Filters out attributes with null values from the event payload ([#204](https://github.com/optimizely/java-sdk/pull/204))
+
 ## 2.1.2
 
 August 1st, 2018

core-api/src/main/java/com/optimizely/ab/event/internal/EventFactory.java

@@ -167,7 +167,19 @@ public LogEvent createConversionEvent(@Nonnull ProjectConfig projectConfig,
     private List<Attribute> buildAttributeList(ProjectConfig projectConfig, Map<String, String> attributes) {
         List<Attribute> attributesList = new ArrayList<Attribute>();
 
-        for (Map.Entry<String, String> entry : attributes.entrySet()) {
+        for (Map.Entry<String, ?> entry : attributes.entrySet()) {
+            // Filter down to the types of values we're allowed to track.
+            // Don't allow Longs, BigIntegers, or BigDecimals - they /can/ theoretically be serialized as JSON numbers
+            // but may take on values that can't be faithfully parsed by the backend.
+            // https://developers.optimizely.com/x/events/api/#Attribute
+            if (entry.getValue() == null ||
+                    !((entry.getValue() instanceof String) ||
+                    (entry.getValue() instanceof Integer) ||
+                    (entry.getValue() instanceof Double) ||
+                    (entry.getValue() instanceof Boolean))) {
+                continue;
+            }
+
             String attributeId = projectConfig.getAttributeId(projectConfig, entry.getKey());
             if(attributeId == null) {
                 continue;