修复代理与日志链路的可靠性问题

tests/proxy/robustness_test.go

@@ -108,6 +108,38 @@ func TestRequestBodyReadFailureReturnsFixed400WithoutUpstream(t *testing.T) {
 	}
 }
 
+func TestRequestBodyOverLimitReturns413WithoutUpstream(t *testing.T) {
+	var upstreamCalls atomic.Int32
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		upstreamCalls.Add(1)
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer upstream.Close()
+	u, _ := url.Parse(upstream.URL)
+	h := newTestHandler(t, u, &captureSubmitter{}, proxy.Options{MaxRequestBytes: 4})
+
+	for _, tc := range []struct {
+		name          string
+		contentLength int64
+	}{
+		{name: "known length", contentLength: 5},
+		{name: "chunked", contentLength: -1},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			req := httptest.NewRequest(http.MethodPost, "http://proxy.test/v1/chat", strings.NewReader("12345"))
+			req.ContentLength = tc.contentLength
+			rec := httptest.NewRecorder()
+			h.ServeHTTP(rec, req)
+			if rec.Code != http.StatusRequestEntityTooLarge || rec.Body.String() != "request body too large\n" {
+				t.Fatalf("response=(%d, %q), want fixed 413", rec.Code, rec.Body.String())
+			}
+		})
+	}
+	if upstreamCalls.Load() != 0 {
+		t.Fatalf("upstream called %d times", upstreamCalls.Load())
+	}
+}
+
 func TestRequestBodyReadFailureWithZeroContentLengthDoesNotReachUpstream(t *testing.T) {
 	var upstreamCalls atomic.Int32
 	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {

tests/proxy/sse_capture_test.go

@@ -643,6 +643,58 @@ func TestGeminiStreamPreservesFunctionCallParts(t *testing.T) {
 	}
 }
 
+func TestGeminiStreamPreservesMultiplePartsByIndex(t *testing.T) {
+	upstream := newSSEUpstream([]string{
+		`data: {"candidates":[{"content":{"parts":[{"text":"hello "},{"functionCall":{"name":"lookup","args":{"q":"weather"}}},{"text":"world"}],"role":"model"},"index":0}]}` + "\n\n",
+		`data: {"candidates":[{"content":{"parts":[{"text":"again"},{"functionCall":{"name":"lookup","args":{"q":"weather"}}},{"text":"!"}],"role":"model"},"finishReason":"STOP","index":0}]}` + "\n\n",
+	})
+	e := requestStreamEntry(t, upstream, "/v1beta/models/gemini-1.5-pro:streamGenerateContent")
+
+	var captured struct {
+		Candidates []struct {
+			Content struct {
+				Parts []map[string]any `json:"parts"`
+			} `json:"content"`
+		} `json:"candidates"`
+	}
+	if err := json.Unmarshal(e.ResponseBody, &captured); err != nil {
+		t.Fatalf("unmarshal assembled Gemini response: %v; body=%s", err, e.ResponseBody)
+	}
+	parts := captured.Candidates[0].Content.Parts
+	if len(parts) != 3 || parts[0]["text"] != "hello again" || parts[2]["text"] != "world!" {
+		t.Fatalf("multiple Gemini parts not preserved: %+v", parts)
+	}
+	if _, ok := parts[1]["functionCall"]; !ok {
+		t.Fatalf("middle functionCall part missing: %+v", parts)
+	}
+}
+
+func TestGeminiStreamAppendsDifferentPartKindsAcrossChunks(t *testing.T) {
+	upstream := newSSEUpstream([]string{
+		`data: {"candidates":[{"content":{"parts":[{"text":"answer"}],"role":"model"},"index":0}]}` + "\n\n",
+		`data: {"candidates":[{"content":{"parts":[{"functionCall":{"name":"lookup","args":{"q":"weather"}}}],"role":"model"},"finishReason":"STOP","index":0}]}` + "\n\n",
+	})
+	e := requestStreamEntry(t, upstream, "/v1beta/models/gemini-1.5-pro:streamGenerateContent")
+
+	var captured struct {
+		Candidates []struct {
+			Content struct {
+				Parts []map[string]any `json:"parts"`
+			} `json:"content"`
+		} `json:"candidates"`
+	}
+	if err := json.Unmarshal(e.ResponseBody, &captured); err != nil {
+		t.Fatalf("unmarshal assembled Gemini response: %v; body=%s", err, e.ResponseBody)
+	}
+	parts := captured.Candidates[0].Content.Parts
+	if len(parts) != 2 || parts[0]["text"] != "answer" {
+		t.Fatalf("different Gemini part kinds were merged: %+v", parts)
+	}
+	if _, ok := parts[1]["functionCall"]; !ok {
+		t.Fatalf("functionCall part missing: %+v", parts)
+	}
+}
+
 func TestUnknownSSEKeepsRawBody(t *testing.T) {
 	e := requestStreamEntry(t, fakeUnknownStreamUpstream(), "/v1/chat/completions")