add test for fix #935

backend/internal/service/antigravity_gateway_service.go

@@ -2164,6 +2164,98 @@ func (s *AntigravityGatewayService) ForwardGemini(ctx context.Context, c *gin.Co
 			}
 		}
 
+		// Gemini 原生请求中的 thoughtSignature 可能来自旧上下文/旧账号，触发上游严格校验后返回
+		// "Corrupted thought signature."。检测到此类 400 时，将 thoughtSignature 清理为 dummy 值后重试一次。
+		signatureCheckBody := respBody
+		if unwrapped, unwrapErr := s.unwrapV1InternalResponse(respBody); unwrapErr == nil && len(unwrapped) > 0 {
+			signatureCheckBody = unwrapped
+		}
+		if resp.StatusCode == http.StatusBadRequest &&
+			s.settingService != nil &&
+			s.settingService.IsSignatureRectifierEnabled(ctx) &&
+			isSignatureRelatedError(signatureCheckBody) &&
+			bytes.Contains(injectedBody, []byte(`"thoughtSignature"`)) {
+			upstreamMsg := sanitizeUpstreamErrorMessage(strings.TrimSpace(extractAntigravityErrorMessage(signatureCheckBody)))
+			upstreamDetail := s.getUpstreamErrorDetail(signatureCheckBody)
+			appendOpsUpstreamError(c, OpsUpstreamErrorEvent{
+				Platform:           account.Platform,
+				AccountID:          account.ID,
+				AccountName:        account.Name,
+				UpstreamStatusCode: resp.StatusCode,
+				UpstreamRequestID:  resp.Header.Get("x-request-id"),
+				Kind:               "signature_error",
+				Message:            upstreamMsg,
+				Detail:             upstreamDetail,
+			})
+
+			logger.LegacyPrintf("service.antigravity_gateway", "Antigravity Gemini account %d: detected signature-related 400, retrying with cleaned thought signatures", account.ID)
+
+			cleanedInjectedBody := CleanGeminiNativeThoughtSignatures(injectedBody)
+			retryWrappedBody, wrapErr := s.wrapV1InternalRequest(projectID, mappedModel, cleanedInjectedBody)
+			if wrapErr == nil {
+				retryResult, retryErr := s.antigravityRetryLoop(antigravityRetryLoopParams{
+					ctx:             ctx,
+					prefix:          prefix,
+					account:         account,
+					proxyURL:        proxyURL,
+					accessToken:     accessToken,
+					action:          upstreamAction,
+					body:            retryWrappedBody,
+					c:               c,
+					httpUpstream:    s.httpUpstream,
+					settingService:  s.settingService,
+					accountRepo:     s.accountRepo,
+					handleError:     s.handleUpstreamError,
+					requestedModel:  originalModel,
+					isStickySession: isStickySession,
+					groupID:         0,
+					sessionHash:     "",
+				})
+				if retryErr == nil {
+					retryResp := retryResult.resp
+					if retryResp.StatusCode < 400 {
+						resp = retryResp
+					} else {
+						retryRespBody, _ := io.ReadAll(io.LimitReader(retryResp.Body, 2<<20))
+						_ = retryResp.Body.Close()
+						retryOpsBody := retryRespBody
+						if retryUnwrapped, unwrapErr := s.unwrapV1InternalResponse(retryRespBody); unwrapErr == nil && len(retryUnwrapped) > 0 {
+							retryOpsBody = retryUnwrapped
+						}
+						appendOpsUpstreamError(c, OpsUpstreamErrorEvent{
+							Platform:           account.Platform,
+							AccountID:          account.ID,
+							AccountName:        account.Name,
+							UpstreamStatusCode: retryResp.StatusCode,
+							UpstreamRequestID:  retryResp.Header.Get("x-request-id"),
+							Kind:               "signature_retry",
+							Message:            sanitizeUpstreamErrorMessage(strings.TrimSpace(extractAntigravityErrorMessage(retryOpsBody))),
+							Detail:             s.getUpstreamErrorDetail(retryOpsBody),
+						})
+						respBody = retryRespBody
+						resp = &http.Response{
+							StatusCode: retryResp.StatusCode,
+							Header:     retryResp.Header.Clone(),
+							Body:       io.NopCloser(bytes.NewReader(retryRespBody)),
+						}
+						contentType = resp.Header.Get("Content-Type")
+					}
+				} else {
+					appendOpsUpstreamError(c, OpsUpstreamErrorEvent{
+						Platform:           account.Platform,
+						AccountID:          account.ID,
+						AccountName:        account.Name,
+						UpstreamStatusCode: 0,
+						Kind:               "signature_retry_request_error",
+						Message:            sanitizeUpstreamErrorMessage(retryErr.Error()),
+					})
+					logger.LegacyPrintf("service.antigravity_gateway", "Antigravity Gemini account %d: signature retry request failed: %v", account.ID, retryErr)
+				}
+			} else {
+				logger.LegacyPrintf("service.antigravity_gateway", "Antigravity Gemini account %d: signature retry wrap failed: %v", account.ID, wrapErr)
+			}
+		}
+
 		// fallback 成功：继续按正常响应处理
 		if resp.StatusCode < 400 {
 			goto handleSuccess

backend/internal/service/antigravity_gateway_service_test.go

@@ -134,6 +134,43 @@ func (s *httpUpstreamStub) DoWithTLS(_ *http.Request, _ string, _ int64, _ int,
 	return s.resp, s.err
 }
 
+type queuedHTTPUpstreamStub struct {
+	responses     []*http.Response
+	errors        []error
+	requestBodies [][]byte
+	callCount     int
+}
+
+func (s *queuedHTTPUpstreamStub) Do(req *http.Request, _ string, _ int64, _ int) (*http.Response, error) {
+	if req != nil && req.Body != nil {
+		body, _ := io.ReadAll(req.Body)
+		s.requestBodies = append(s.requestBodies, body)
+		req.Body = io.NopCloser(bytes.NewReader(body))
+	} else {
+		s.requestBodies = append(s.requestBodies, nil)
+	}
+
+	idx := s.callCount
+	s.callCount++
+
+	var resp *http.Response
+	if idx < len(s.responses) {
+		resp = s.responses[idx]
+	}
+	var err error
+	if idx < len(s.errors) {
+		err = s.errors[idx]
+	}
+	if resp == nil && err == nil {
+		return nil, errors.New("unexpected upstream call")
+	}
+	return resp, err
+}
+
+func (s *queuedHTTPUpstreamStub) DoWithTLS(req *http.Request, proxyURL string, accountID int64, concurrency int, _ bool) (*http.Response, error) {
+	return s.Do(req, proxyURL, accountID, concurrency)
+}
+
 type antigravitySettingRepoStub struct{}
 
 func (s *antigravitySettingRepoStub) Get(ctx context.Context, key string) (*Setting, error) {
@@ -556,6 +593,92 @@ func TestAntigravityGatewayService_ForwardGemini_BillsWithMappedModel(t *testing
 	require.Equal(t, mappedModel, result.Model)
 }
 
+func TestAntigravityGatewayService_ForwardGemini_RetriesCorruptedThoughtSignature(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	writer := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(writer)
+
+	body, err := json.Marshal(map[string]any{
+		"contents": []map[string]any{
+			{"role": "user", "parts": []map[string]any{{"text": "hello"}}},
+			{"role": "model", "parts": []map[string]any{{"text": "thinking", "thought": true, "thoughtSignature": "sig_bad_1"}}},
+			{"role": "model", "parts": []map[string]any{{"functionCall": map[string]any{"name": "toolA", "args": map[string]any{"x": 1}}, "thoughtSignature": "sig_bad_2"}}},
+		},
+	})
+	require.NoError(t, err)
+
+	req := httptest.NewRequest(http.MethodPost, "/antigravity/v1beta/models/gemini-3.1-pro-preview:streamGenerateContent", bytes.NewReader(body))
+	c.Request = req
+
+	firstRespBody := []byte(`{"response":{"error":{"code":400,"message":"Corrupted thought signature.","status":"INVALID_ARGUMENT"}}}`)
+	secondRespBody := []byte("data: {\"response\":{\"candidates\":[{\"content\":{\"parts\":[{\"text\":\"ok\"}]},\"finishReason\":\"STOP\"}],\"usageMetadata\":{\"promptTokenCount\":8,\"candidatesTokenCount\":3}}}\n\n")
+
+	upstream := &queuedHTTPUpstreamStub{
+		responses: []*http.Response{
+			{
+				StatusCode: http.StatusBadRequest,
+				Header: http.Header{
+					"Content-Type": []string{"application/json"},
+					"X-Request-Id": []string{"req-sig-1"},
+				},
+				Body: io.NopCloser(bytes.NewReader(firstRespBody)),
+			},
+			{
+				StatusCode: http.StatusOK,
+				Header: http.Header{
+					"Content-Type": []string{"text/event-stream"},
+					"X-Request-Id": []string{"req-sig-2"},
+				},
+				Body: io.NopCloser(bytes.NewReader(secondRespBody)),
+			},
+		},
+	}
+
+	svc := &AntigravityGatewayService{
+		settingService: NewSettingService(&antigravitySettingRepoStub{}, &config.Config{Gateway: config.GatewayConfig{MaxLineSize: defaultMaxLineSize}}),
+		tokenProvider:  &AntigravityTokenProvider{},
+		httpUpstream:   upstream,
+	}
+
+	const originalModel = "gemini-3.1-pro-preview"
+	const mappedModel = "gemini-3.1-pro-high"
+	account := &Account{
+		ID:          7,
+		Name:        "acc-gemini-signature",
+		Platform:    PlatformAntigravity,
+		Type:        AccountTypeOAuth,
+		Status:      StatusActive,
+		Concurrency: 1,
+		Credentials: map[string]any{
+			"access_token": "token",
+			"model_mapping": map[string]any{
+				originalModel: mappedModel,
+			},
+		},
+	}
+
+	result, err := svc.ForwardGemini(context.Background(), c, account, originalModel, "streamGenerateContent", true, body, false)
+	require.NoError(t, err)
+	require.NotNil(t, result)
+	require.Equal(t, mappedModel, result.Model)
+	require.Len(t, upstream.requestBodies, 2, "signature error should trigger exactly one retry")
+
+	firstReq := string(upstream.requestBodies[0])
+	secondReq := string(upstream.requestBodies[1])
+	require.Contains(t, firstReq, `"thoughtSignature":"sig_bad_1"`)
+	require.Contains(t, firstReq, `"thoughtSignature":"sig_bad_2"`)
+	require.Contains(t, secondReq, `"thoughtSignature":"skip_thought_signature_validator"`)
+	require.NotContains(t, secondReq, `"thoughtSignature":"sig_bad_1"`)
+	require.NotContains(t, secondReq, `"thoughtSignature":"sig_bad_2"`)
+
+	raw, ok := c.Get(OpsUpstreamErrorsKey)
+	require.True(t, ok)
+	events, ok := raw.([]*OpsUpstreamErrorEvent)
+	require.True(t, ok)
+	require.NotEmpty(t, events)
+	require.Equal(t, "signature_error", events[0].Kind)
+}
+
 // TestStreamUpstreamResponse_UsageAndFirstToken
 // 验证：usage 字段可被累积/覆盖更新，并且能记录首 token 时间
 func TestStreamUpstreamResponse_UsageAndFirstToken(t *testing.T) {

backend/internal/service/gemini_native_signature_cleaner_test.go

@@ -0,0 +1,75 @@
+package service
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/antigravity"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCleanGeminiNativeThoughtSignatures_ReplacesNestedThoughtSignatures(t *testing.T) {
+	input := []byte(`{
+		"contents": [
+			{
+				"role": "user",
+				"parts": [{"text": "hello"}]
+			},
+			{
+				"role": "model",
+				"parts": [
+					{"text": "thinking", "thought": true, "thoughtSignature": "sig_1"},
+					{"functionCall": {"name": "toolA", "args": {"k": "v"}}, "thoughtSignature": "sig_2"}
+				]
+			}
+		],
+		"cachedContent": {
+			"parts": [{"text": "cached", "thoughtSignature": "sig_3"}]
+		},
+		"signature": "keep_me"
+	}`)
+
+	cleaned := CleanGeminiNativeThoughtSignatures(input)
+
+	var got map[string]any
+	require.NoError(t, json.Unmarshal(cleaned, &got))
+
+	require.NotContains(t, string(cleaned), `"thoughtSignature":"sig_1"`)
+	require.NotContains(t, string(cleaned), `"thoughtSignature":"sig_2"`)
+	require.NotContains(t, string(cleaned), `"thoughtSignature":"sig_3"`)
+	require.Contains(t, string(cleaned), `"thoughtSignature":"`+antigravity.DummyThoughtSignature+`"`)
+	require.Contains(t, string(cleaned), `"signature":"keep_me"`)
+}
+
+func TestCleanGeminiNativeThoughtSignatures_InvalidJSONReturnsOriginal(t *testing.T) {
+	input := []byte(`{"contents":[invalid-json]}`)
+
+	cleaned := CleanGeminiNativeThoughtSignatures(input)
+
+	require.Equal(t, input, cleaned)
+}
+
+func TestReplaceThoughtSignaturesRecursive_OnlyReplacesTargetField(t *testing.T) {
+	input := map[string]any{
+		"thoughtSignature": "sig_root",
+		"signature":        "keep_signature",
+		"nested": []any{
+			map[string]any{
+				"thoughtSignature": "sig_nested",
+				"signature":        "keep_nested_signature",
+			},
+		},
+	}
+
+	got, ok := replaceThoughtSignaturesRecursive(input).(map[string]any)
+	require.True(t, ok)
+	require.Equal(t, antigravity.DummyThoughtSignature, got["thoughtSignature"])
+	require.Equal(t, "keep_signature", got["signature"])
+
+	nested, ok := got["nested"].([]any)
+	require.True(t, ok)
+	nestedMap, ok := nested[0].(map[string]any)
+	require.True(t, ok)
+	require.Equal(t, antigravity.DummyThoughtSignature, nestedMap["thoughtSignature"])
+	require.Equal(t, "keep_nested_signature", nestedMap["signature"])
+}