Fix Parsing ActionCallDeltaMessageContent (#1446)

CHANGELOG.md

@@ -21,6 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `Agent` unintentionally modifying `stream` for all Prompt Drivers.
 - `StructureVisualizer.base_url` for setting the base URL on the url generated by `StructureVisualizer.to_url()`.
 - `StructureVisualizer.query_params` for setting query parameters on the url generated by `StructureVisualizer.to_url()`.
+- Parsing `ActionCallDeltaMessageContent`s with empty string `partial_input`s.
 
 ## [1.0.0] - 2024-12-09
 

griptape/common/prompt_stack/contents/action_call_message_content.py

@@ -37,7 +37,7 @@ def from_deltas(cls, deltas: Sequence[BaseDeltaMessageContent]) -> ActionCallMes
 
         if tag is not None and name is not None and path is not None:
             try:
-                parsed_input = json.loads(json_input)
+                parsed_input = json.loads(json_input or "{}")
             except json.JSONDecodeError as exc:
                 raise ValueError("Invalid JSON input for ToolAction") from exc
             action = ToolAction(tag=tag, name=name, path=path, input=parsed_input)

tests/unit/common/contents/test_action_call_message_content.py

@@ -21,6 +21,7 @@ def test_from_deltas(self):
             ActionCallDeltaMessageContent(tag="testtag"),
             ActionCallDeltaMessageContent(name="TestName"),
             ActionCallDeltaMessageContent(path="test_tag"),
+            ActionCallDeltaMessageContent(partial_input=""),
             ActionCallDeltaMessageContent(partial_input='{"foo":'),
             ActionCallDeltaMessageContent(partial_input='"bar"}'),
         ]