SOLR-18373: remove NamedList.asShallowMap/get(String,int) and SolrParams.toNamedList

solr/core/src/java/org/apache/solr/core/SolrCore.java

@@ -3033,9 +3033,9 @@ public static void postDecorateResponse(
                 + "'");
       }
       if (echoParams == EchoParamStyle.EXPLICIT) {
-        responseHeader.add("params", req.getOriginalParams().toNamedList());
+        responseHeader.add("params", new SimpleOrderedMap<>(req.getOriginalParams()));
       } else if (echoParams == EchoParamStyle.ALL) {
-        responseHeader.add("params", req.getParams().toNamedList());
+        responseHeader.add("params", new SimpleOrderedMap<>(req.getParams()));
       }
     }
   }

solr/core/src/java/org/apache/solr/core/SolrXmlConfig.java

@@ -28,6 +28,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -126,12 +127,11 @@ public static NodeConfig fromConfig(
 
     // It should go inside the fillSolrSection method but
     // since it is arranged as a separate section it is placed here
-    Map<String, String> coreAdminHandlerActions =
-        readNodeListAsNamedList(root.get("coreAdminHandlerActions"), "<coreAdminHandlerActions>")
-            .asShallowMap()
-            .entrySet()
-            .stream()
-            .collect(Collectors.toMap(Entry::getKey, item -> item.getValue().toString()));
+    Map<String, String> coreAdminHandlerActions = new LinkedHashMap<>();
+    for (Entry<String, Object> entry :
+        readNodeListAsNamedList(root.get("coreAdminHandlerActions"), "<coreAdminHandlerActions>")) {
+      coreAdminHandlerActions.put(entry.getKey(), entry.getValue().toString());
+    }
 
     UpdateShardHandlerConfig updateConfig;
     if (deprecatedUpdateConfig == null) {

solr/core/src/java/org/apache/solr/handler/DumpRequestHandler.java

@@ -43,7 +43,7 @@ public class DumpRequestHandler extends RequestHandlerBase {
   @SuppressWarnings({"unchecked"})
   public void handleRequestBody(SolrQueryRequest req, SolrQueryResponse rsp) throws IOException {
     // Show params
-    rsp.add("params", req.getParams().toNamedList());
+    rsp.add("params", new SimpleOrderedMap<>(req.getParams()));
     String[] parts = req.getParams().getParams("urlTemplateValues");
     if (parts != null && parts.length > 0) {
       Map<String, String> map = new LinkedHashMap<>();

solr/core/src/java/org/apache/solr/handler/component/CombinedQueryComponent.java

@@ -455,10 +455,10 @@ protected void mergeIds(ResponseBuilder rb, ShardRequest sreq) {
     populateNextCursorMarkFromMergedShards(rb);
 
     if (thereArePartialResults) {
-      rb.rsp
-          .getResponseHeader()
-          .asShallowMap()
-          .put(SolrQueryResponse.RESPONSE_HEADER_PARTIAL_RESULTS_KEY, Boolean.TRUE);
+      updateResponseHeader(
+          rb.rsp.getResponseHeader(),
+          SolrQueryResponse.RESPONSE_HEADER_PARTIAL_RESULTS_KEY,
+          Boolean.TRUE);
     }
     if (segmentTerminatedEarly != null) {
       final Object existingSegmentTerminatedEarly =
@@ -472,12 +472,10 @@ protected void mergeIds(ResponseBuilder rb, ShardRequest sreq) {
                 SolrQueryResponse.RESPONSE_HEADER_SEGMENT_TERMINATED_EARLY_KEY,
                 segmentTerminatedEarly);
       } else if (!Boolean.TRUE.equals(existingSegmentTerminatedEarly) && segmentTerminatedEarly) {
-        rb.rsp
-            .getResponseHeader()
-            .remove(SolrQueryResponse.RESPONSE_HEADER_SEGMENT_TERMINATED_EARLY_KEY);
-        rb.rsp
-            .getResponseHeader()
-            .add(SolrQueryResponse.RESPONSE_HEADER_SEGMENT_TERMINATED_EARLY_KEY, true);
+        updateResponseHeader(
+            rb.rsp.getResponseHeader(),
+            SolrQueryResponse.RESPONSE_HEADER_SEGMENT_TERMINATED_EARLY_KEY,
+            true);
       }
     }
     if (maxHitsTerminatedEarly) {

solr/core/src/java/org/apache/solr/handler/component/QueryComponent.java

@@ -1237,10 +1237,10 @@ protected void mergeIds(ResponseBuilder rb, ShardRequest sreq) {
     populateNextCursorMarkFromMergedShards(rb);
 
     if (thereArePartialResults) {
-      rb.rsp
-          .getResponseHeader()
-          .asShallowMap()
-          .put(SolrQueryResponse.RESPONSE_HEADER_PARTIAL_RESULTS_KEY, Boolean.TRUE);
+      updateResponseHeader(
+          rb.rsp.getResponseHeader(),
+          SolrQueryResponse.RESPONSE_HEADER_PARTIAL_RESULTS_KEY,
+          Boolean.TRUE);
     }
     if (segmentTerminatedEarly != null) {
       final Object existingSegmentTerminatedEarly =
@@ -1255,14 +1255,10 @@ protected void mergeIds(ResponseBuilder rb, ShardRequest sreq) {
                 segmentTerminatedEarly);
       } else if (!Boolean.TRUE.equals(existingSegmentTerminatedEarly)
           && Boolean.TRUE.equals(segmentTerminatedEarly)) {
-        rb.rsp
-            .getResponseHeader()
-            .remove(SolrQueryResponse.RESPONSE_HEADER_SEGMENT_TERMINATED_EARLY_KEY);
-        rb.rsp
-            .getResponseHeader()
-            .add(
-                SolrQueryResponse.RESPONSE_HEADER_SEGMENT_TERMINATED_EARLY_KEY,
-                segmentTerminatedEarly);
+        updateResponseHeader(
+            rb.rsp.getResponseHeader(),
+            SolrQueryResponse.RESPONSE_HEADER_SEGMENT_TERMINATED_EARLY_KEY,
+            segmentTerminatedEarly);
       }
     }
     if (maxHitsTerminatedEarly) {
@@ -1284,6 +1280,11 @@ protected void mergeIds(ResponseBuilder rb, ShardRequest sreq) {
     }
   }
 
+  @SuppressWarnings("unchecked")
+  protected static void updateResponseHeader(NamedList<Object> header, String key, Object value) {
+    ((SimpleOrderedMap<Object>) header).put(key, value);
+  }
+
   protected void setResultIdsAndResponseDocs(
       ResponseBuilder rb,
       ShardDocQueue shardDocQueue,

solr/core/src/java/org/apache/solr/handler/designer/DefaultSchemaSuggester.java

@@ -185,9 +185,7 @@ public ManagedIndexSchema adaptExistingFieldToData(
       fieldProps.add("multiValued", true);
       fieldProps.remove("name");
       fieldProps.remove("type");
-      schema =
-          schema.replaceField(
-              schemaField.getName(), schemaField.getType(), fieldProps.asShallowMap());
+      schema = schema.replaceField(schemaField.getName(), schemaField.getType(), fieldProps);
     }
     // TODO: other "healing" type operations here ... but we have to be careful about overriding
     // explicit user changes such as a user making a text field a string field, we wouldn't want to

solr/core/src/java/org/apache/solr/jersey/SolrJacksonMapper.java

@@ -27,7 +27,9 @@
 import jakarta.ws.rs.ext.ContextResolver;
 import jakarta.ws.rs.ext.Provider;
 import java.io.IOException;
+import java.util.Map;
 import org.apache.solr.common.util.NamedList;
+import org.apache.solr.common.util.SimpleOrderedMap;
 
 /** Customizes the ObjectMapper settings used for serialization/deserialization in Jersey */
 @SuppressWarnings("rawtypes")
@@ -48,6 +50,7 @@ public static ObjectMapper getObjectMapper() {
   private static ObjectMapper createObjectMapper() {
     final SimpleModule customTypeModule = new SimpleModule();
     customTypeModule.addSerializer(new NamedListSerializer(NamedList.class));
+    customTypeModule.addSerializer(new SimpleOrderedMapSerializer(SimpleOrderedMap.class));
 
     return new ObjectMapper()
         // TODO Should failOnUnknown=false be made available on a "permissive" object mapper instead
@@ -70,7 +73,40 @@ public NamedListSerializer(Class<NamedList> nlClazz) {
     @Override
     public void serialize(NamedList value, JsonGenerator gen, SerializerProvider provider)
         throws IOException {
-      gen.writeObject(value.asShallowMap());
+      // SimpleOrderedMap goes through SimpleOrderedMapSerializer below instead. asMap(0) avoids
+      // recursing into this same serializer for plain NamedLists.
+      gen.writeObject(value.asMap(0));
+    }
+  }
+
+  /**
+   * Writes a {@link SimpleOrderedMap} out directly via its {@link Map} entries, without the copy
+   * {@link NamedListSerializer} needs to dodge infinite recursion -- {@link SimpleOrderedMap} is
+   * already a {@link Map}, so there is nothing to convert.
+   */
+  public static class SimpleOrderedMapSerializer extends StdSerializer<SimpleOrderedMap> {
+
+    public SimpleOrderedMapSerializer() {
+      this(null);
+    }
+
+    public SimpleOrderedMapSerializer(Class<SimpleOrderedMap> somClazz) {
+      super(somClazz);
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public void serialize(SimpleOrderedMap value, JsonGenerator gen, SerializerProvider provider)
+        throws IOException {
+      final Map<String, Object> map = (Map<String, Object>) value;
+      gen.writeStartObject();
+      for (Map.Entry<String, Object> entry : map.entrySet()) {
+        // defaultSerializeField() doesn't honor NON_NULL inclusion itself -- skip nulls here.
+        if (entry.getValue() != null) {
+          provider.defaultSerializeField(entry.getKey(), entry.getValue(), gen);
+        }
+      }
+      gen.writeEndObject();
     }
   }
 }

solr/core/src/java/org/apache/solr/packagemanager/PackageManager.java

@@ -278,24 +278,24 @@ public Map<String, SolrPackageInstance> getPackagesDeployedAsClusterLevelPlugins
     Map<String, String> packageVersions = new HashMap<>();
     // map of package name to multiple values of pluginMeta(Map<String, String>)
     Map<String, Set<PluginMeta>> packagePlugins = new HashMap<>();
-    Map<String, Object> result;
+    Object pluginsValue;
     try {
       NamedList<Object> response =
           solrClient.request(
               new GenericV2SolrRequest(SolrRequest.METHOD.GET, PackageUtils.CLUSTERPROPS_PATH));
       Integer statusCode = (Integer) response._get(List.of("responseHeader", "status"), null);
       if (statusCode == null || statusCode == ErrorCode.NOT_FOUND.code) {
         // Cluster props doesn't exist, that means there are no cluster level plugins installed.
-        result = Map.of();
+        pluginsValue = null;
       } else {
-        result = response.asShallowMap();
+        pluginsValue = response.get(ContainerPluginsApi.PLUGIN);
       }
     } catch (SolrServerException | IOException ex) {
       throw new SolrException(ErrorCode.SERVER_ERROR, ex);
     }
     @SuppressWarnings({"unchecked"})
     Map<String, Object> clusterPlugins =
-        (Map<String, Object>) result.getOrDefault(ContainerPluginsApi.PLUGIN, Map.of());
+        pluginsValue != null ? (Map<String, Object>) pluginsValue : Map.of();
     for (Map.Entry<String, Object> entry : clusterPlugins.entrySet()) {
       PluginMeta pluginMeta;
       try {
@@ -421,16 +421,14 @@ private Pair<List<String>, List<String>> deployCollectionPackage(
 
       // Get package params
       try {
-        boolean packageParamsExist =
-            solrClient
-                .request(
-                    new GenericV2SolrRequest(
-                            SolrRequest.METHOD.GET,
-                            PackageUtils.getCollectionParamsPath(collection) + "/packages")
-                        .setRequiresCollection(
-                            false) /* Making a collection-request, but already baked into path */)
-                .asShallowMap()
-                .containsKey("params");
+        NamedList<Object> collectionParams =
+            solrClient.request(
+                new GenericV2SolrRequest(
+                        SolrRequest.METHOD.GET,
+                        PackageUtils.getCollectionParamsPath(collection) + "/packages")
+                    .setRequiresCollection(
+                        false) /* Making a collection-request, but already baked into path */);
+        boolean packageParamsExist = collectionParams.get("params") != null;
         SolrCLI.postJsonToSolr(
             solrClient,
             PackageUtils.getCollectionParamsPath(collection),

solr/core/src/java/org/apache/solr/update/IndexFingerprint.java

@@ -200,7 +200,7 @@ public static IndexFingerprint fromObject(Object o) {
     if (o instanceof Map) {
       map = (Map<String, Object>) o;
     } else if (o instanceof NamedList) {
-      map = ((NamedList<Object>) o).asShallowMap();
+      map = new SimpleOrderedMap<>((NamedList<Object>) o);
     } else {
       throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, "Unknown type " + o);
     }

solr/core/src/java/org/apache/solr/util/PivotListEntry.java

@@ -80,6 +80,7 @@ public <T> T extract(NamedList<T> pivotList) {
     }
     // otherwise...
     // scan starting at the min/optional index
-    return pivotList.get(this.getName(), this.minIndex);
+    final int idx = pivotList.indexOf(this.getName(), this.minIndex);
+    return idx == -1 ? null : pivotList.getVal(idx);
   }
 }

solr/core/src/test/org/apache/solr/handler/component/MockResponseBuilder.java

@@ -20,7 +20,7 @@
 import java.util.List;
 import org.apache.solr.common.params.ShardParams;
 import org.apache.solr.common.params.SolrParams;
-import org.apache.solr.common.util.NamedList;
+import org.apache.solr.common.util.SimpleOrderedMap;
 import org.apache.solr.request.SolrQueryRequest;
 import org.apache.solr.response.SolrQueryResponse;
 import org.apache.solr.schema.IndexSchema;
@@ -48,7 +48,7 @@ public static MockResponseBuilder create() {
     SchemaField uniqueIdField = new SchemaField("id", new StrField());
 
     // we need this because QueryComponent adds a property to it.
-    NamedList<Object> responseHeader = new NamedList<>();
+    SimpleOrderedMap<Object> responseHeader = new SimpleOrderedMap<>();
 
     // the mock implementations
     Mockito.when(request.getSchema()).thenReturn(indexSchema);

solr/core/src/test/org/apache/solr/jersey/SolrJacksonMapperTest.java

@@ -0,0 +1,80 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF 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.
+ */
+
+package org.apache.solr.jersey;
+
+import static org.hamcrest.Matchers.equalTo;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.apache.solr.SolrTestCaseJ4;
+import org.apache.solr.common.util.NamedList;
+import org.apache.solr.common.util.SimpleOrderedMap;
+import org.junit.Test;
+
+/** Unit tests for {@link SolrJacksonMapper}'s NamedList/SimpleOrderedMap serialization. */
+public class SolrJacksonMapperTest extends SolrTestCaseJ4 {
+
+  @Test
+  public void testSimpleOrderedMapSerializesDirectlyWithoutRecursing() throws Exception {
+    final SimpleOrderedMap<Object> top = new SimpleOrderedMap<>();
+    top.add("status", 0);
+
+    final NamedList<Object> nestedPlainNamedList = new NamedList<>();
+    nestedPlainNamedList.add("nestedKey", "nestedVal");
+    top.add("nested_plain_namedlist", nestedPlainNamedList);
+
+    final SimpleOrderedMap<Object> nestedSimpleOrderedMap = new SimpleOrderedMap<>();
+    nestedSimpleOrderedMap.add("innerKey", 42);
+    top.add("nested_simple_ordered_map", nestedSimpleOrderedMap);
+
+    final ObjectMapper mapper = SolrJacksonMapper.getObjectMapper();
+    final String json = mapper.writeValueAsString(top);
+
+    assertThat(
+        json,
+        equalTo(
+            "{\"status\":0,"
+                + "\"nested_plain_namedlist\":{\"nestedKey\":\"nestedVal\"},"
+                + "\"nested_simple_ordered_map\":{\"innerKey\":42}}"));
+  }
+
+  @Test
+  public void testPlainNamedListStillSerializesViaAsMap() throws Exception {
+    final NamedList<Object> namedList = new NamedList<>();
+    namedList.add("key", "value");
+
+    final ObjectMapper mapper = SolrJacksonMapper.getObjectMapper();
+    final String json = mapper.writeValueAsString(namedList);
+
+    assertThat(json, equalTo("{\"key\":\"value\"}"));
+  }
+
+  @Test
+  public void testSimpleOrderedMapOmitsNullValuesLikeNamedListDoes() throws Exception {
+    final NamedList<Object> namedListWithNull = new NamedList<>();
+    namedListWithNull.add("present", "val");
+    namedListWithNull.add("absent", null);
+
+    final SimpleOrderedMap<Object> somWithNull = new SimpleOrderedMap<>();
+    somWithNull.add("present", "val");
+    somWithNull.add("absent", null);
+
+    final ObjectMapper mapper = SolrJacksonMapper.getObjectMapper();
+    assertThat(mapper.writeValueAsString(namedListWithNull), equalTo("{\"present\":\"val\"}"));
+    assertThat(mapper.writeValueAsString(somWithNull), equalTo("{\"present\":\"val\"}"));
+  }
+}

solr/core/src/test/org/apache/solr/search/facet/TestCloudJSONFacetSKG.java

@@ -44,6 +44,7 @@
 import org.apache.solr.common.params.SolrParams;
 import org.apache.solr.common.util.IOUtils;
 import org.apache.solr.common.util.NamedList;
+import org.apache.solr.common.util.SimpleOrderedMap;
 import org.apache.solr.embedded.JettySolrRunner;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
@@ -499,7 +500,7 @@ private void assertFacetSKGsAreCorrect(
       assertEquals(
           "Unexpected keys in facet response",
           expectedKeys,
-          actualFacetResponse.asShallowMap().keySet());
+          new SimpleOrderedMap<>(actualFacetResponse).keySet());
     }
   }
 

solr/core/src/test/org/apache/solr/util/TestUtils.java

@@ -70,9 +70,9 @@ public void testNamedLists() {
     assertEquals("one", map.getName(0));
     map.setName(0, "ONE");
     assertEquals("ONE", map.getName(0));
-    assertEquals(Integer.valueOf(100), map.get("one", 1));
+    assertEquals(Integer.valueOf(100), map.getVal(map.indexOf("one", 1)));
     assertEquals(4, map.indexOf(null, 1));
-    assertNull(map.get(null, 1));
+    assertNull(map.getVal(map.indexOf(null, 1)));
 
     map = new SimpleOrderedMap<>();
     map.add("one", 1);