[BUG-8620] Add ProGuard keep rules for Jackson naming strategy fields

Prevents R8 from obfuscating PropertyNamingStrategies.SNAKE_CASE and
PropertyNamingStrategy.SNAKE_CASE fields that the Java SDK's
JacksonSerializer accesses via reflection. Without these rules, apps
with Jackson on the classpath get NoClassDefFoundError in
DefaultJsonSerializer.

Defense-in-depth for BUG-8620 (primary fix is in java-sdk).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: muzahidul-opti

proguard-rules.txt

@@ -38,6 +38,17 @@
 
 # Safely ignore warnings about other libraries since we are using Gson
 -dontwarn com.fasterxml.jackson.**
+
+# Keep Jackson naming strategy fields used via reflection by the Java SDK serializer (BUG-8620).
+# When Jackson is on the classpath, JacksonSerializer uses reflection to access SNAKE_CASE.
+# Without these rules, R8 obfuscates the field names, causing NoSuchFieldException.
+-keepclassmembers class com.fasterxml.jackson.databind.PropertyNamingStrategies {
+    public static *;
+}
+-keepclassmembers class com.fasterxml.jackson.databind.PropertyNamingStrategy {
+    public static *;
+}
+
 -dontwarn org.json.**
 
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