修复接续流的增量bug

internal/sse/consumer.go

@@ -54,9 +54,11 @@ func CollectStream(resp *http.Response, thinkingEnabled bool, closeBody bool) Co
 		}
 		for _, p := range result.Parts {
 			if p.Type == "thinking" {
-				thinking.WriteString(p.Text)
+				trimmed := TrimContinuationOverlap(thinking.String(), p.Text)
+				thinking.WriteString(trimmed)
 			} else {
-				text.WriteString(p.Text)
+				trimmed := TrimContinuationOverlap(text.String(), p.Text)
+				text.WriteString(trimmed)
 			}
 		}
 		return true

internal/sse/consumer_test.go

@@ -0,0 +1,33 @@
+package sse
+
+import (
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+)
+
+func TestCollectStreamDedupesContinueSnapshotReplay(t *testing.T) {
+	body := strings.Join([]string{
+		`data: {"v":{"response":{"fragments":[{"id":2,"type":"THINK","content":"我们","references":[],"stage_id":1}]}}}`,
+		``,
+		`data: {"p":"response/fragments/-1/content","o":"APPEND","v":"被"}`,
+		``,
+		`data: {"v":"问到"}`,
+		``,
+		`data: {"p":"response/status","v":"INCOMPLETE"}`,
+		``,
+		`data: {"v":{"response":{"fragments":[{"id":2,"type":"THINK","content":"我们被问到继续","references":[],"stage_id":1}]}}}`,
+		``,
+		`data: {"v":"分析"}`,
+		``,
+		`data: {"p":"response/status","v":"FINISHED"}`,
+		``,
+	}, "\n")
+
+	resp := &http.Response{Body: io.NopCloser(strings.NewReader(body))}
+	got := CollectStream(resp, true, true)
+	if got.Thinking != "我们被问到继续分析" {
+		t.Fatalf("unexpected thinking after dedupe: %q", got.Thinking)
+	}
+}

internal/sse/dedupe.go

@@ -0,0 +1,22 @@
+package sse
+
+import "strings"
+
+// TrimContinuationOverlap removes the already-seen prefix when DeepSeek
+// continue rounds resend the full fragment snapshot instead of only the new
+// suffix. Non-overlapping chunks are returned unchanged.
+func TrimContinuationOverlap(existing, incoming string) string {
+	if incoming == "" {
+		return ""
+	}
+	if existing == "" {
+		return incoming
+	}
+	if strings.HasPrefix(incoming, existing) {
+		return incoming[len(existing):]
+	}
+	if strings.HasPrefix(existing, incoming) {
+		return ""
+	}
+	return incoming
+}

internal/sse/dedupe_test.go

@@ -0,0 +1,30 @@
+package sse
+
+import "testing"
+
+func TestTrimContinuationOverlapReturnsSuffixForSnapshotReplay(t *testing.T) {
+	existing := "我们被问到：题目"
+	incoming := "我们被问到：题目继续分析"
+	got := TrimContinuationOverlap(existing, incoming)
+	if got != "继续分析" {
+		t.Fatalf("expected suffix only, got %q", got)
+	}
+}
+
+func TestTrimContinuationOverlapDropsStaleShorterSnapshot(t *testing.T) {
+	existing := "我们被问到：题目继续分析"
+	incoming := "我们被问到：题目"
+	got := TrimContinuationOverlap(existing, incoming)
+	if got != "" {
+		t.Fatalf("expected stale snapshot to be dropped, got %q", got)
+	}
+}
+
+func TestTrimContinuationOverlapPreservesNormalIncrement(t *testing.T) {
+	existing := "我们"
+	incoming := "被"
+	got := TrimContinuationOverlap(existing, incoming)
+	if got != "被" {
+		t.Fatalf("expected normal increment unchanged, got %q", got)
+	}
+}