[ML][Inference] minor cleanup for inference (#50444)

Author: benwtrent

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/InferenceToXContentCompressor.java

@@ -43,8 +43,8 @@ public static <T extends ToXContentObject> String deflate(T objectToCompress) th
     }
 
     static <T> T inflate(String compressedString,
-                                CheckedFunction<XContentParser, T, IOException> parserFunction,
-                                NamedXContentRegistry xContentRegistry) throws IOException {
+                         CheckedFunction<XContentParser, T, IOException> parserFunction,
+                         NamedXContentRegistry xContentRegistry) throws IOException {
         try(XContentParser parser = XContentHelper.createParser(xContentRegistry,
             LoggingDeprecationHandler.INSTANCE,
             inflate(compressedString, MAX_INFLATED_BYTES),

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/inference/ingest/InferenceProcessor.java

@@ -28,7 +28,6 @@
 import org.elasticsearch.ingest.Processor;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.xpack.core.ml.action.InternalInferModelAction;
-import org.elasticsearch.xpack.core.ml.inference.results.InferenceResults;
 import org.elasticsearch.xpack.core.ml.inference.results.WarningInferenceResults;
 import org.elasticsearch.xpack.core.ml.inference.trainedmodel.ClassificationConfig;
 import org.elasticsearch.xpack.core.ml.inference.trainedmodel.InferenceConfig;
@@ -151,12 +150,8 @@ void mutateDocument(InternalInferModelAction.Response response, IngestDocument i
         if (response.getInferenceResults().isEmpty()) {
             throw new ElasticsearchStatusException("Unexpected empty inference response", RestStatus.INTERNAL_SERVER_ERROR);
         }
-        InferenceResults inferenceResults = response.getInferenceResults().get(0);
-        if (inferenceResults instanceof WarningInferenceResults) {
-            inferenceResults.writeResult(ingestDocument, this.targetField);
-        } else {
-            response.getInferenceResults().get(0).writeResult(ingestDocument, this.targetField);
-        }
+        assert response.getInferenceResults().size() == 1;
+        response.getInferenceResults().get(0).writeResult(ingestDocument, this.targetField);
         ingestDocument.setFieldValue(targetField + "." + MODEL_ID, modelId);
     }