Fix ScoreFunction: variants are optional (#752)

Signed-off-by: 西狩 <923568791@qq.com>

CHANGELOG.md

@@ -55,6 +55,7 @@ This section is for maintaining a changelog for all breaking changes for the cli
 ### Fixed
 - Fix partial success results for msearch_template ([#709](https://github.com/opensearch-project/opensearch-java/pull/709))
 - Fix deserialization of node stats response ([#745](https://github.com/opensearch-project/opensearch-java/pull/745))
+- Fix ScoreFunction: variants are optional ([#752](https://github.com/opensearch-project/opensearch-java/pull/752))
 
 ### Security
 

java-client/src/main/java/org/opensearch/client/json/DelegatingJsonpMapper.java

@@ -0,0 +1,73 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.client.json;
+
+import jakarta.json.spi.JsonProvider;
+import jakarta.json.stream.JsonGenerator;
+import jakarta.json.stream.JsonParser;
+import javax.annotation.Nullable;
+
+public abstract class DelegatingJsonpMapper implements JsonpMapper {
+
+    protected final JsonpMapper mapper;
+
+    public DelegatingJsonpMapper(JsonpMapper mapper) {
+        this.mapper = mapper;
+    }
+
+    @Override
+    public JsonProvider jsonProvider() {
+        return mapper.jsonProvider();
+    }
+
+    @Override
+    public <T> T deserialize(JsonParser parser, Class<T> clazz) {
+        return mapper.deserialize(parser, clazz);
+    }
+
+    @Override
+    public <T> void serialize(T value, JsonGenerator generator) {
+        mapper.serialize(value, generator);
+    }
+
+    @Override
+    public boolean ignoreUnknownFields() {
+        return mapper.ignoreUnknownFields();
+    }
+
+    @Override
+    @Nullable
+    public <T> T attribute(String name) {
+        return mapper.attribute(name);
+    }
+}

java-client/src/main/java/org/opensearch/client/json/JsonpMapperBase.java

@@ -36,13 +36,42 @@
 import jakarta.json.stream.JsonGenerator;
 import jakarta.json.stream.JsonParser;
 import java.lang.reflect.Field;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 import javax.annotation.Nullable;
 
 public abstract class JsonpMapperBase implements JsonpMapper {
 
     /** Get a serializer when none of the builtin ones are applicable */
     protected abstract <T> JsonpDeserializer<T> getDefaultDeserializer(Class<T> clazz);
 
+    private Map<String, Object> attributes;
+
+    @Nullable
+    @Override
+    @SuppressWarnings("unchecked")
+    public <T> T attribute(String name) {
+        return attributes == null ? null : (T) attributes.get(name);
+    }
+
+    /**
+     * Updates attributes to a copy of the current ones with an additional key/value pair.
+     *
+     * Mutates the current mapper, intended to be used in implementations of {@link #withAttribute(String, Object)}
+     */
+    protected JsonpMapperBase addAttribute(String name, Object value) {
+        if (attributes == null) {
+            this.attributes = Collections.singletonMap(name, value);
+        } else {
+            Map<String, Object> newAttrs = new HashMap<>(attributes.size() + 1);
+            newAttrs.putAll(attributes);
+            newAttrs.put(name, value);
+            this.attributes = newAttrs;
+        }
+        return this;
+    }
+
     @Override
     public <T> T deserialize(JsonParser parser, Class<T> clazz) {
         JsonpDeserializer<T> deserializer = findDeserializer(clazz);

java-client/src/main/java/org/opensearch/client/json/JsonpMapperFeatures.java

@@ -0,0 +1,51 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.client.json;
+
+/**
+ * Defines attribute names for {@link JsonpMapper} features.
+ */
+public class JsonpMapperFeatures {
+
+    /**
+     *
+     */
+    public static final String SERIALIZE_TYPED_KEYS = JsonpMapperFeatures.class.getName() + ":SERIALIZE_TYPED_KEYS";
+
+    /**
+     * Disables custom variants in union types (false by default). Used in tests to avoid interpreting wrong variant kinds as a custom
+     * extension.
+     */
+    public static final String FORBID_CUSTOM_VARIANTS = JsonpMapperFeatures.class.getName() + ":FORBID_CUSTOM_VARIANTS";
+
+}

java-client/src/main/java/org/opensearch/client/json/JsonpMappingException.java

@@ -0,0 +1,152 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.client.json;
+
+import jakarta.json.stream.JsonLocation;
+import jakarta.json.stream.JsonParser;
+import jakarta.json.stream.JsonParsingException;
+import java.util.LinkedList;
+import java.util.regex.Pattern;
+
+/**
+ * A mapping exception. The exception message contains the JSON path and location where the problem happened.
+ */
+public class JsonpMappingException extends JsonParsingException {
+    private final LinkedList<Object> path = new LinkedList<>();
+    private Object ref;
+
+    public JsonpMappingException(String message, JsonLocation location) {
+        super(message, location);
+    }
+
+    public JsonpMappingException(String message, Throwable cause, JsonLocation location) {
+        super(message, cause, location);
+    }
+
+    public JsonpMappingException(Throwable cause, JsonLocation location) {
+        super(cause.toString(), cause, location);
+    }
+
+    private static final Pattern identifier = Pattern.compile("[_a-zA-Z][_a-zA-Z0-9]*");
+
+    @Override
+    public String getMessage() {
+        StringBuilder sb = new StringBuilder("Error deserializing");
+        if (ref != null) {
+            sb.append(' ');
+            String className = ref.getClass().getName();
+            if (className.endsWith("$Builder")) {
+                sb.append(className, 0, className.length() - "$Builder".length());
+            } else {
+                sb.append(className);
+            }
+        }
+        sb.append(": ").append(super.getMessage());
+
+        if (!path.isEmpty()) {
+            sb.append(" (JSON path: ");
+            path(sb);
+            sb.append(") ");
+        }
+
+        sb.append(getLocation());
+        return sb.toString();
+    }
+
+    /**
+     * The JSON path where this exception happened.
+     */
+    public String path() {
+        StringBuilder sb = new StringBuilder();
+        path(sb);
+        return sb.toString();
+    }
+
+    // Package-visible for testing
+    void path(StringBuilder sb) {
+        String sep = "";
+        for (Object item : path) {
+            if (item instanceof Integer) {
+                sb.append("[").append(((Integer) item).intValue()).append("]");
+            } else {
+                String str = item.toString();
+                if (identifier.matcher(str).matches()) {
+                    sb.append(sep).append(item);
+                } else {
+                    sb.append("['").append(str).append("']");
+                }
+            }
+            sep = ".";
+        }
+    }
+
+    public JsonpMappingException prepend(Object ref, String name) {
+        return prepend0(ref, name);
+    }
+
+    public JsonpMappingException prepend(Object ref, int idx) {
+        return prepend0(ref, idx);
+    }
+
+    private JsonpMappingException prepend0(Object ref, Object pathItem) {
+        if (pathItem != null) {
+            this.path.addFirst(pathItem);
+        }
+        // Keep the deepest object reference in the JSON hierarchy
+        if (this.ref == null) {
+            this.ref = ref;
+        }
+        return this;
+    }
+
+    public static JsonpMappingException from(Throwable cause, Object ref, String name, JsonParser parser) {
+        return from0(cause, ref, name, parser);
+    }
+
+    public static JsonpMappingException from(Throwable cause, int index, JsonParser parser) {
+        return from0(cause, null, index, parser);
+    }
+
+    private static JsonpMappingException from0(Throwable cause, Object ref, Object pathItem, JsonParser parser) {
+        JsonpMappingException jme;
+
+        if (cause instanceof JsonpMappingException) {
+            jme = (JsonpMappingException) cause;
+        } else {
+            jme = new JsonpMappingException(cause, parser.getLocation());
+        }
+
+        return jme.prepend0(ref, pathItem);
+    }
+}
+