chore: Add metadata field to GoogleJsonError ErrorInfo class.

google-api-client/src/main/java/com/google/api/client/googleapis/json/GoogleJsonError.java

@@ -22,9 +22,11 @@
 import com.google.api.client.util.Data;
 import com.google.api.client.util.Key;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 
 /**
  * Data class representing the Google JSON error response content, as documented for example in <a
@@ -191,6 +193,7 @@ public static class Details extends GenericJson {
     @Key private String detail;
     @Key private String reason;
     @Key private List<ParameterViolations> parameterViolations;
+    @Key private Map<String, String> metadata;
 
     public String getType() {
       return type;
@@ -228,6 +231,14 @@ public List<ParameterViolations> getParameterViolations() {
     public void setParameterViolations(List<ParameterViolations> parameterViolations) {
       this.parameterViolations = ImmutableList.copyOf(parameterViolations);
     }
+
+    public Map<String, String> getMetadata() {
+      return metadata;
+    }
+
+    public void setMetadata(Map<String, String> metadata) {
+      this.metadata = ImmutableMap.copyOf(metadata);
+    }
   }
 
   public static class ParameterViolations {

google-api-client/src/test/java/com/google/api/client/googleapis/json/GoogleJsonErrorTest.java

@@ -27,8 +27,10 @@
 import com.google.api.client.testing.http.MockHttpTransport;
 import com.google.api.client.testing.http.MockLowLevelHttpRequest;
 import com.google.api.client.testing.http.MockLowLevelHttpResponse;
+import com.google.common.collect.ImmutableMap;
 import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.util.Map;
 import junit.framework.TestCase;
 
 /**
@@ -199,4 +201,25 @@ public void testParse_withReasonInDetails() throws Exception {
         JSON_PARSER.parse(DETAILS_ERROR), JSON_PARSER.parse(FACTORY.toString(errorResponse)));
     assertNotNull(errorResponse.getDetails().get(2).getReason());
   }
+
+  public void testParse_withMetadataInDetails() throws Exception {
+    InputStream errorContent =
+        GoogleJsonErrorTest.class.getResourceAsStream("errorWithMetadataInDetails.json");
+
+    HttpTransport transport =
+        new ErrorTransport(
+            new MockLowLevelHttpResponse()
+                .setContent(errorContent)
+                .setContentType(Json.MEDIA_TYPE)
+                .setStatusCode(HttpStatusCodes.STATUS_CODE_FORBIDDEN));
+    HttpRequest request =
+        transport.createRequestFactory().buildGetRequest(HttpTesting.SIMPLE_GENERIC_URL);
+    request.setThrowExceptionOnExecuteError(false);
+    HttpResponse response = request.execute();
+    com.google.api.client.googleapis.json.GoogleJsonError errorResponse =
+        com.google.api.client.googleapis.json.GoogleJsonError.parse(FACTORY, response);
+
+    Map<String, String> metadata = errorResponse.getDetails().get(0).getMetadata();
+    assertEquals(metadata, ImmutableMap.of("service", "translate.googleapis.com"));
+  }
 }

google-api-client/src/test/resources/com/google/api/client/googleapis/json/errorWithMetadataInDetails.json

@@ -0,0 +1,17 @@
+{
+  "error": {
+    "code": 400,
+    "message": "API key not valid. Please pass a valid API key.",
+    "status": "INVALID_ARGUMENT",
+    "details": [
+      {
+        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
+        "reason": "API_KEY_INVALID",
+        "domain": "googleapis.com",
+        "metadata": {
+          "service": "translate.googleapis.com"
+        }
+      }
+    ]
+  }
+}