From 26933c2f592bda25df735c555620a2a978cfefb6 Mon Sep 17 00:00:00 2001
From: EthanGuo-coder <188665641+EthanGuo-coder@users.noreply.github.com>
Date: Thu, 14 May 2026 08:03:50 -0700
Subject: [PATCH] fix(agent/gemini-cloudcode): seed delta defaults for
 reasoning-only stream chunks

_make_stream_chunk built delta_kwargs with only `role`, so a reasoning-only
chunk produced a SimpleNamespace without a `.content` attribute. Downstream
consumers that read `delta.content` then raised AttributeError on Gemini 2.5
Flash, where the thinking delta arrives before any content delta.

Seed `content`, `tool_calls`, `reasoning`, and `reasoning_content` as None
up front, matching the pattern already used in gemini_native_adapter.py.
Key-present arguments still override the defaults.

Fixes #24974
References: Related open PR #24984 (luyao618) applies the same 1-line fix; this PR adds a regression test that #24984 omits
Co-Authored-By: Claude <noreply@anthropic.com>
---
 agent/gemini_cloudcode_adapter.py    |  8 +++++++-
 tests/agent/test_gemini_cloudcode.py | 29 ++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/agent/gemini_cloudcode_adapter.py b/agent/gemini_cloudcode_adapter.py
index 5bc42e3aad7..222327807be 100644
--- a/agent/gemini_cloudcode_adapter.py
+++ b/agent/gemini_cloudcode_adapter.py
@@ -450,7 +450,13 @@ def _make_stream_chunk(
     finish_reason: Optional[str] = None,
     reasoning: str = "",
 ) -> _GeminiStreamChunk:
-    delta_kwargs: Dict[str, Any] = {"role": "assistant"}
+    delta_kwargs: Dict[str, Any] = {
+        "role": "assistant",
+        "content": None,
+        "tool_calls": None,
+        "reasoning": None,
+        "reasoning_content": None,
+    }
     if content:
         delta_kwargs["content"] = content
     if tool_call_delta is not None:
diff --git a/tests/agent/test_gemini_cloudcode.py b/tests/agent/test_gemini_cloudcode.py
index dc2b1b15311..480f562aa64 100644
--- a/tests/agent/test_gemini_cloudcode.py
+++ b/tests/agent/test_gemini_cloudcode.py
@@ -913,6 +913,35 @@ class TestTranslateStreamEvent:
         assert chunks[-1].choices[0].finish_reason == "tool_calls"
 
 
+class TestMakeStreamChunk:
+    def test_reasoning_only_chunk_has_content_none(self):
+        from agent.gemini_cloudcode_adapter import _make_stream_chunk
+
+        chunk = _make_stream_chunk(model="m", reasoning="think")
+        delta = chunk.choices[0].delta
+        assert delta.content is None
+        assert delta.reasoning == "think"
+
+    def test_content_only_chunk_has_reasoning_none(self):
+        from agent.gemini_cloudcode_adapter import _make_stream_chunk
+
+        chunk = _make_stream_chunk(model="m", content="hello")
+        delta = chunk.choices[0].delta
+        assert delta.content == "hello"
+        assert delta.reasoning is None
+        assert delta.tool_calls is None
+
+    def test_finish_only_chunk_has_all_fields_none(self):
+        from agent.gemini_cloudcode_adapter import _make_stream_chunk
+
+        chunk = _make_stream_chunk(model="m", finish_reason="stop")
+        delta = chunk.choices[0].delta
+        assert delta.content is None
+        assert delta.reasoning is None
+        assert delta.tool_calls is None
+        assert chunk.choices[0].finish_reason == "stop"
+
+
 class TestGeminiCloudCodeClient:
     def test_client_exposes_openai_interface(self):
         from agent.gemini_cloudcode_adapter import GeminiCloudCodeClient