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fix(translator): restore usageMetadata in Gemini responses from Antigravity #1298

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Merged
luispater merged 1 commit into from
Jan 29, 2026
+110 −1
Merged

fix(translator): restore usageMetadata in Gemini responses from Antigravity #1298

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16 changes: 15 additions & 1 deletion internal/translator/antigravity/gemini/antigravity_gemini_response.go
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,7 @@ func ConvertAntigravityResponseToGemini(ctx context.Context, _ string, originalR
responseResult := gjson.GetBytes(rawJSON, "response")
if responseResult.Exists() {
chunk = []byte(responseResult.Raw)
chunk = restoreUsageMetadata(chunk)
}
} else {
chunkTemplate := "[]"
Expand Down Expand Up @@ -76,11 +77,24 @@ func ConvertAntigravityResponseToGemini(ctx context.Context, _ string, originalR
func ConvertAntigravityResponseToGeminiNonStream(_ context.Context, _ string, originalRequestRawJSON, requestRawJSON, rawJSON []byte, _ *any) string {
responseResult := gjson.GetBytes(rawJSON, "response")
if responseResult.Exists() {
return responseResult.Raw
chunk := restoreUsageMetadata([]byte(responseResult.Raw))
return string(chunk)
}
return string(rawJSON)
}

func GeminiTokenCount(ctx context.Context, count int64) string {
return fmt.Sprintf(`{"totalTokens":%d,"promptTokensDetails":[{"modality":"TEXT","tokenCount":%d}]}`, count, count)
}

// restoreUsageMetadata renames cpaUsageMetadata back to usageMetadata.
// The executor renames usageMetadata to cpaUsageMetadata in non-terminal chunks
// to preserve usage data while hiding it from clients that don't expect it.
// When returning standard Gemini API format, we must restore the original name.
func restoreUsageMetadata(chunk []byte) []byte {
if cpaUsage := gjson.GetBytes(chunk, "cpaUsageMetadata"); cpaUsage.Exists() {
chunk, _ = sjson.SetRawBytes(chunk, "usageMetadata", []byte(cpaUsage.Raw))
chunk, _ = sjson.DeleteBytes(chunk, "cpaUsageMetadata")
Comment on lines +96 to +97
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@gemini-code-assist gemini-code-assist bot Jan 29, 2026

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medium

Ignoring errors from sjson operations can lead to returning a partially modified JSON object. If SetRawBytes succeeds but DeleteBytes fails, the resulting chunk will contain both usageMetadata and cpaUsageMetadata. It's safer to handle these errors and return the original chunk on failure to ensure the rename operation is atomic.

                res, err := sjson.SetRawBytes(chunk, "usageMetadata", []byte(cpaUsage.Raw))
                if err != nil {
                        return chunk
                }
                res, err = sjson.DeleteBytes(res, "cpaUsageMetadata")
                if err != nil {
                        return chunk
                }
                chunk = res

}
return chunk
}
95 changes: 95 additions & 0 deletions internal/translator/antigravity/gemini/antigravity_gemini_response_test.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,95 @@
package gemini

import (
"context"
"testing"
)

func TestRestoreUsageMetadata(t *testing.T) {
tests := []struct {
name string
input []byte
expected string
}{
{
name: "cpaUsageMetadata renamed to usageMetadata",
input: []byte(`{"modelVersion":"gemini-3-pro","cpaUsageMetadata":{"promptTokenCount":100,"candidatesTokenCount":200}}`),
expected: `{"modelVersion":"gemini-3-pro","usageMetadata":{"promptTokenCount":100,"candidatesTokenCount":200}}`,
},
{
name: "no cpaUsageMetadata unchanged",
input: []byte(`{"modelVersion":"gemini-3-pro","usageMetadata":{"promptTokenCount":100}}`),
expected: `{"modelVersion":"gemini-3-pro","usageMetadata":{"promptTokenCount":100}}`,
},
{
name: "empty input",
input: []byte(`{}`),
expected: `{}`,
},
}

for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
result := restoreUsageMetadata(tt.input)
if string(result) != tt.expected {
t.Errorf("restoreUsageMetadata() = %s, want %s", string(result), tt.expected)
}
})
}
}

func TestConvertAntigravityResponseToGeminiNonStream(t *testing.T) {
tests := []struct {
name string
input []byte
expected string
}{
{
name: "cpaUsageMetadata restored in response",
input: []byte(`{"response":{"modelVersion":"gemini-3-pro","cpaUsageMetadata":{"promptTokenCount":100}}}`),
expected: `{"modelVersion":"gemini-3-pro","usageMetadata":{"promptTokenCount":100}}`,
},
{
name: "usageMetadata preserved",
input: []byte(`{"response":{"modelVersion":"gemini-3-pro","usageMetadata":{"promptTokenCount":100}}}`),
expected: `{"modelVersion":"gemini-3-pro","usageMetadata":{"promptTokenCount":100}}`,
},
}

for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
result := ConvertAntigravityResponseToGeminiNonStream(context.Background(), "", nil, nil, tt.input, nil)
if result != tt.expected {
t.Errorf("ConvertAntigravityResponseToGeminiNonStream() = %s, want %s", result, tt.expected)
}
})
}
}

func TestConvertAntigravityResponseToGeminiStream(t *testing.T) {
ctx := context.WithValue(context.Background(), "alt", "")

tests := []struct {
name string
input []byte
expected string
}{
{
name: "cpaUsageMetadata restored in streaming response",
input: []byte(`data: {"response":{"modelVersion":"gemini-3-pro","cpaUsageMetadata":{"promptTokenCount":100}}}`),
expected: `{"modelVersion":"gemini-3-pro","usageMetadata":{"promptTokenCount":100}}`,
},
}

for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
results := ConvertAntigravityResponseToGemini(ctx, "", nil, nil, tt.input, nil)
if len(results) != 1 {
t.Fatalf("expected 1 result, got %d", len(results))
}
if results[0] != tt.expected {
t.Errorf("ConvertAntigravityResponseToGemini() = %s, want %s", results[0], tt.expected)
}
})
}
}
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