fix: ignore null fields

Author: mogita

MIGRATION_v2_to_v3.md

@@ -203,6 +203,26 @@ The general renaming rules:
 | `MembershipLevel` | `MembershipLevelResponse` | |
 | `ThreadedComment` | `ThreadedCommentResponse` | |
 
+## JSON Serialization of Optional Fields
+
+Optional fields in request objects are now omitted from the JSON body when not set, instead of being sent as explicit `null`. Previously, every unset field was serialized as `null`, which caused the backend to zero out existing values on partial updates.
+
+**Before:**
+```python
+client.update_app(enforce_unique_usernames="no")
+# Wire: {"enforce_unique_usernames":"no","webhook_url":null,"multi_tenant_enabled":null,...}
+# Backend: sets enforce_unique_usernames="no", but ALSO resets webhook_url="", multi_tenant_enabled=false, etc.
+```
+
+**After:**
+```python
+client.update_app(enforce_unique_usernames="no")
+# Wire: {"enforce_unique_usernames":"no"}
+# Backend: sets enforce_unique_usernames="no", all other fields preserved
+```
+
+List and dict fields are still serialized when set (including as empty `[]`/`{}`), so you can continue to send an empty list to clear a list field. Unset collection fields (`None`) are now also omitted.
+
 ## Getting Help
 
 - [Stream documentation](https://getstream.io/docs/)

getstream/base.py

@@ -25,6 +25,16 @@
 import ijson
 
 
+def _strip_none(obj):
+    """Recursively remove None values from dicts so unset optional fields
+    are omitted from the JSON body instead of being sent as null."""
+    if isinstance(obj, dict):
+        return {k: _strip_none(v) for k, v in obj.items() if v is not None}
+    if isinstance(obj, list):
+        return [_strip_none(item) for item in obj]
+    return obj
+
+
 def build_path(path: str, path_params: Optional[Dict[str, Any]]) -> str:
     if path_params is None:
         return path
@@ -169,6 +179,8 @@ def _request_sync(
         data_type: Optional[Type[T]] = None,
     ):
         kwargs = kwargs or {}
+        if "json" in kwargs and kwargs["json"] is not None:
+            kwargs["json"] = _strip_none(kwargs["json"])
         url_path, url_full, endpoint, attrs = self._prepare_request(
             method, path, query_params, kwargs
         )
@@ -348,6 +360,8 @@ async def _request_async(
         data_type: Optional[Type[T]] = None,
     ):
         kwargs = kwargs or {}
+        if "json" in kwargs and kwargs["json"] is not None:
+            kwargs["json"] = _strip_none(kwargs["json"])
         query_params = query_params or {}
         url_path, url_full, endpoint, attrs = self._prepare_request(
             method, path, query_params, kwargs