From f6d19a329c68e41ab1751e53e14054791faf6bdc Mon Sep 17 00:00:00 2001
From: sususu <suchangshan@foxmail.com>
Date: Fri, 4 Sep 2026 18:08:20 +0800
Subject: [PATCH] fix(gemini): ensure functionResponse normalizes to user role
 in Gemini request normalizer

---
 .../gemini/gemini/gemini_gemini_request.go     | 18 +++++++++++++++---
 .../gemini/gemini_gemini_request_test.go       | 17 +++++++++++++++++
 2 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/internal/translator/gemini/gemini/gemini_gemini_request.go b/internal/translator/gemini/gemini/gemini_gemini_request.go
index e8026f98..c309d105 100644
--- a/internal/translator/gemini/gemini/gemini_gemini_request.go
+++ b/internal/translator/gemini/gemini/gemini_gemini_request.go
@@ -78,7 +78,11 @@ func ConvertGeminiRequestToGemini(_ string, inputRawJSON []byte, _ bool) []byte
 		contents.ForEach(func(_, value gjson.Result) bool {
 			role := value.Get("role").String()
 			if role != "user" && role != "model" {
-				role = nextGeminiRole(prevRole)
+				if translatorcommon.ContentHasGeminiFunctionResponse([]byte(value.Raw)) {
+					role = "user"
+				} else {
+					role = nextGeminiRole(prevRole)
+				}
 				rolesChanged = true
 			}
 			prevRole = role
@@ -91,7 +95,11 @@ func ConvertGeminiRequestToGemini(_ string, inputRawJSON []byte, _ bool) []byte
 				role := value.Get("role").String()
 				item := []byte(value.Raw)
 				if role != "user" && role != "model" {
-					role = nextGeminiRole(prevRole)
+					if translatorcommon.ContentHasGeminiFunctionResponse([]byte(value.Raw)) {
+						role = "user"
+					} else {
+						role = nextGeminiRole(prevRole)
+					}
 					item, _ = sjson.SetBytes(item, "role", role)
 				}
 				prevRole = role
@@ -105,7 +113,11 @@ func ConvertGeminiRequestToGemini(_ string, inputRawJSON []byte, _ bool) []byte
 		contents.ForEach(func(_ gjson.Result, value gjson.Result) bool {
 			role := value.Get("role").String()
 			if role != "user" && role != "model" {
-				role = nextGeminiRole(prevRole)
+				if translatorcommon.ContentHasGeminiFunctionResponse([]byte(value.Raw)) {
+					role = "user"
+				} else {
+					role = nextGeminiRole(prevRole)
+				}
 				out, _ = sjson.SetBytes(out, fmt.Sprintf("contents.%d.role", idx), role)
 			}
 			prevRole = role
diff --git a/internal/translator/gemini/gemini/gemini_gemini_request_test.go b/internal/translator/gemini/gemini/gemini_gemini_request_test.go
index f5402ef0..ba70a905 100644
--- a/internal/translator/gemini/gemini/gemini_gemini_request_test.go
+++ b/internal/translator/gemini/gemini/gemini_gemini_request_test.go
@@ -253,3 +253,20 @@ func TestBackfillEmptyFunctionResponseNames_MultipleGroups(t *testing.T) {
 		t.Errorf("Expected second group name 'Grep', got '%s'", name1)
 	}
 }
+
+func TestConvertGeminiRequestToGemini_FunctionResponseWithInvalidRoleNormalizesToUser(t *testing.T) {
+	inputJSON := []byte(`{
+		"contents": [
+			{"role": "user", "parts": [{"text": "reminder"}]},
+			{"role": "invalid", "parts": [{"functionResponse": {"name": "lookup", "response": {}}}]}
+		]
+	}`)
+	out := ConvertGeminiRequestToGemini("gemini-3-flash", inputJSON, false)
+	contents := gjson.GetBytes(out, "contents").Array()
+	if len(contents) != 2 {
+		t.Fatalf("expected 2 contents, got %d", len(contents))
+	}
+	if got := contents[1].Get("role").String(); got != "user" {
+		t.Fatalf("functionResponse invalid role should normalize to user, got %q", got)
+	}
+}
-- 
2.51.2