SolrRequest.getParams never null; and clarify mutability

solr/core/src/java/org/apache/solr/cloud/RecoveryStrategy.java

@@ -282,7 +282,6 @@ private void commitOnLeader(String leaderBaseUrl, String coreName)
       throws SolrServerException, IOException {
     try (SolrClient client = recoverySolrClientBuilder(leaderBaseUrl, coreName).build()) {
       UpdateRequest ureq = new UpdateRequest();
-      ureq.setParams(new ModifiableSolrParams());
       // ureq.getParams().set(DistributedUpdateProcessor.COMMIT_END_POINT, true);
       // ureq.getParams().set(UpdateParams.OPEN_SEARCHER, onlyLeaderIndexes);
       // Why do we need to open searcher if "onlyLeaderIndexes"?

solr/core/src/java/org/apache/solr/cloud/api/collections/CollectionHandlingUtils.java

@@ -250,7 +250,6 @@ static UpdateResponse softCommit(String baseUrl, String coreName)
             .withSocketTimeout(120000, TimeUnit.MILLISECONDS)
             .build()) {
       UpdateRequest ureq = new UpdateRequest();
-      ureq.setParams(new ModifiableSolrParams());
       ureq.setAction(AbstractUpdateRequest.ACTION.COMMIT, false, true, true);
       return ureq.process(client);
     }

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

@@ -79,6 +79,7 @@ public void handleRequestBody(SolrQueryRequest req, SolrQueryResponse rsp) throw
     }
     try {
       SolrParams params = req.getParams();
+      assert params != null;
       UpdateRequestProcessorChain processorChain = req.getCore().getUpdateProcessorChain(params);
 
       UpdateRequestProcessor processor = processorChain.createProcessor(req, rsp);

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

@@ -450,7 +450,7 @@ static Long getCheckSum(Checksum checksum, Path f) {
   private volatile IndexFetcher currentIndexFetcher;
 
   public IndexFetchResult doFetch(SolrParams solrParams, boolean forceReplication) {
-    String leaderUrl = solrParams == null ? null : solrParams.get(LEADER_URL, null);
+    String leaderUrl = solrParams.get(LEADER_URL, null);
     if (!indexFetchLock.tryLock()) return IndexFetchResult.LOCK_OBTAIN_FAILED;
     if (core.getCoreContainer().isShutDown()) {
       log.warn("I was asked to replicate but CoreContainer is shutting down");
@@ -1196,7 +1196,7 @@ private void setupPolling(String intervalStr) {
           try {
             log.debug("Polling for index modifications");
             markScheduledExecutionStart();
-            IndexFetchResult fetchResult = doFetch(null, false);
+            IndexFetchResult fetchResult = doFetch(SolrParams.of(), false);
             if (pollListener != null) pollListener.onComplete(core, fetchResult);
           } catch (Exception e) {
             log.error("Exception in fetching index", e);

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

@@ -18,7 +18,6 @@
 
 import java.io.IOException;
 import java.util.Arrays;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Map;
@@ -53,10 +52,6 @@ public static void addExperimentalFormatWarning(SolrQueryResponse rsp) {
   public static boolean handleCommit(
       SolrQueryRequest req, UpdateRequestProcessor processor, SolrParams params, boolean force)
       throws IOException {
-    if (params == null) {
-      params = new MapSolrParams(new HashMap<>());
-    }
-
     boolean optimize = params.getBool(UpdateParams.OPTIMIZE, false);
     boolean commit = params.getBool(UpdateParams.COMMIT, false);
     boolean softCommit = params.getBool(UpdateParams.SOFT_COMMIT, false);
@@ -97,8 +92,6 @@ public static void validateCommitParams(SolrParams params) {
 
   /** Modify UpdateCommand based on request parameters */
   public static void updateCommit(CommitUpdateCommand cmd, SolrParams params) {
-    if (params == null) return;
-
     cmd.openSearcher = params.getBool(UpdateParams.OPEN_SEARCHER, cmd.openSearcher);
     cmd.waitSearcher = params.getBool(UpdateParams.WAIT_SEARCHER, cmd.waitSearcher);
     cmd.softCommit = params.getBool(UpdateParams.SOFT_COMMIT, cmd.softCommit);
@@ -114,13 +107,7 @@ public static void updateCommit(CommitUpdateCommand cmd, SolrParams params) {
   public static boolean handleRollback(
       SolrQueryRequest req, UpdateRequestProcessor processor, SolrParams params, boolean force)
       throws IOException {
-    if (params == null) {
-      params = new MapSolrParams(new HashMap<>());
-    }
-
-    boolean rollback = params.getBool(UpdateParams.ROLLBACK, false);
-
-    if (rollback || force) {
+    if (force || params.getBool(UpdateParams.ROLLBACK, false)) {
       RollbackUpdateCommand cmd = new RollbackUpdateCommand(req);
       processor.processRollback(cmd);
       return true;

solr/core/src/java/org/apache/solr/handler/api/V2ApiUtils.java

@@ -91,9 +91,6 @@ public static void squashIntoNamedListWithoutHeader(
   }
 
   public static String getMediaTypeFromWtParam(SolrParams params, String defaultMediaType) {
-    if (params == null) {
-      return defaultMediaType;
-    }
     final String wtParam = params.get(WT);
     if (StrUtils.isBlank(wtParam)) return defaultMediaType;
 

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

@@ -78,10 +78,6 @@ public SampleDocuments parseDocsFromStream(
       return SampleDocuments.NONE;
     }
 
-    if (params == null) {
-      params = new ModifiableSolrParams();
-    }
-
     Long streamSize = stream.getSize();
     if (streamSize != null && streamSize > MAX_STREAM_SIZE) {
       throw new SolrException(

solr/core/src/java/org/apache/solr/update/processor/IgnoreCommitOptimizeUpdateProcessorFactory.java

@@ -50,13 +50,13 @@ public class IgnoreCommitOptimizeUpdateProcessorFactory extends UpdateRequestPro
 
   @Override
   public void init(final NamedList<?> args) {
-    SolrParams params = (args != null) ? args.toSolrParams() : null;
-    if (params == null) {
+    if (args == null) {
       errorCode = ErrorCode.FORBIDDEN; // default is 403 error
       responseMsg = DEFAULT_RESPONSE_MSG;
       ignoreOptimizeOnly = false;
       return;
     }
+    SolrParams params = args.toSolrParams();
 
     ignoreOptimizeOnly = params.getBool("ignoreOptimizeOnly", false);
 

solr/core/src/test/org/apache/solr/cloud/LeaderFailureAfterFreshStartTest.java

@@ -38,7 +38,6 @@
 import org.apache.solr.common.SolrInputDocument;
 import org.apache.solr.common.cloud.Replica;
 import org.apache.solr.common.cloud.ZkStateReader;
-import org.apache.solr.common.params.ModifiableSolrParams;
 import org.junit.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -241,8 +240,6 @@ protected void indexDoc(Object... fields) throws IOException, SolrServerExceptio
 
     UpdateRequest ureq = new UpdateRequest();
     ureq.add(doc);
-    ModifiableSolrParams params = new ModifiableSolrParams();
-    ureq.setParams(params);
     ureq.process(cloudClient);
   }
 

solr/core/src/test/org/apache/solr/cloud/PeerSyncReplicationTest.java

@@ -43,7 +43,6 @@
 import org.apache.solr.common.SolrInputDocument;
 import org.apache.solr.common.cloud.Replica;
 import org.apache.solr.common.cloud.ZkStateReader;
-import org.apache.solr.common.params.ModifiableSolrParams;
 import org.apache.solr.core.CoreContainer;
 import org.apache.solr.metrics.SolrMetricManager;
 import org.junit.Test;
@@ -369,8 +368,6 @@ protected void indexDoc(Object... fields) throws IOException, SolrServerExceptio
 
     UpdateRequest ureq = new UpdateRequest();
     ureq.add(doc);
-    ModifiableSolrParams params = new ModifiableSolrParams();
-    ureq.setParams(params);
     ureq.process(cloudClient);
   }
 

solr/core/src/test/org/apache/solr/cloud/TestStressInPlaceUpdates.java

@@ -625,11 +625,8 @@ protected long addDocAndGetVersion(Object... fields) throws Exception {
     SolrInputDocument doc = new SolrInputDocument();
     addFields(doc, fields);
 
-    ModifiableSolrParams params = new ModifiableSolrParams();
-    params.add("versions", "true");
-
     UpdateRequest ureq = new UpdateRequest();
-    ureq.setParams(params);
+    ureq.getParams().set("versions", true);
     ureq.add(doc);
     UpdateResponse resp;
 
@@ -647,10 +644,10 @@ protected long addDocAndGetVersion(Object... fields) throws Exception {
 
   protected long deleteDocAndGetVersion(
       String id, ModifiableSolrParams params, boolean deleteByQuery) throws Exception {
-    params.add("versions", "true");
-
     UpdateRequest ureq = new UpdateRequest();
-    ureq.setParams(params);
+    ureq.getParams().add(params);
+    ureq.getParams().set("versions", true);
+
     if (deleteByQuery) {
       ureq.deleteByQuery("id:" + id);
     } else {

solr/core/src/test/org/apache/solr/handler/TestSampleDocumentsLoader.java

@@ -52,7 +52,7 @@ public void setup() throws IOException {
 
   @Test
   public void testJson() throws Exception {
-    loadTestDocs(null, new File(exampleDir, "films/films.json"), 500, 500);
+    loadTestDocs(SolrParams.of(), new File(exampleDir, "films/films.json"), 500, 500);
   }
 
   @Test
@@ -78,7 +78,7 @@ public void testCsv() throws Exception {
 
   @Test
   public void testSolrXml() throws Exception {
-    loadTestDocs(null, new File(exampleDir, "films/films.xml"), 1000, 1000);
+    loadTestDocs(SolrParams.of(), new File(exampleDir, "films/films.xml"), 1000, 1000);
   }
 
   protected List<SolrInputDocument> loadTestDocs(

solr/core/src/test/org/apache/solr/handler/admin/TestApiFramework.java

@@ -250,7 +250,6 @@ public void read(SolrQueryRequest req, SolrQueryResponse rsp) {
 
   private static SolrQueryResponse v2ApiInvoke(
       ApiBag bag, String uri, String method, SolrParams params, InputStream payload) {
-    if (params == null) params = new ModifiableSolrParams();
     SolrQueryResponse rsp = new SolrQueryResponse();
     HashMap<String, String> templateVals = new HashMap<>();
     Api[] currentApi = new Api[1];

solr/core/src/test/org/apache/solr/update/processor/TemplateUpdateProcessorTest.java

@@ -47,13 +47,15 @@ public void after() throws Exception {
 
   public void testSimple() throws Exception {
 
-    ModifiableSolrParams params =
-        new ModifiableSolrParams()
-            .add("processor", "template")
-            .add("template.field", "id:{firstName}_{lastName}")
-            .add("template.field", "another:{lastName}_{firstName}")
-            .add("template.field", "missing:{lastName}_{unKnown}");
-    AddUpdateCommand cmd = new AddUpdateCommand(new LocalSolrQueryRequest(null, params));
+    var cmd =
+        new AddUpdateCommand(
+            new LocalSolrQueryRequest(
+                null,
+                new ModifiableSolrParams()
+                    .add("processor", "template")
+                    .add("template.field", "id:{firstName}_{lastName}")
+                    .add("template.field", "another:{lastName}_{firstName}")
+                    .add("template.field", "missing:{lastName}_{unKnown}")));
 
     cmd.solrDoc = new SolrInputDocument();
     cmd.solrDoc.addField("firstName", "Tom");
@@ -69,14 +71,11 @@ public void testSimple() throws Exception {
     SolrInputDocument solrDoc = new SolrInputDocument();
     solrDoc.addField("id", "1");
 
-    params =
-        new ModifiableSolrParams()
-            .add("processor", "template")
-            .add("commit", "true")
-            .add("template.field", "x_s:key_{id}");
-    params.add("commit", "true");
     UpdateRequest add = new UpdateRequest().add(solrDoc);
-    add.setParams(params);
+    add.getParams()
+        .add("processor", "template")
+        .add("template.field", "x_s:key_{id}")
+        .add("commit", "true");
     NamedList<Object> result =
         cluster
             .getSolrClient()

solr/core/src/test/org/apache/solr/update/processor/TolerantUpdateProcessorTest.java

@@ -136,7 +136,7 @@ public void testInvalidAdds() throws IOException {
     assertAddsSucceedWithErrors(
         "tolerant-chain-max-errors-10",
         Arrays.asList(new SolrInputDocument[] {invalidDoc1}),
-        null,
+        SolrParams.of(),
         "(unknown)");
 
     // a valid doc
@@ -149,7 +149,7 @@ public void testInvalidAdds() throws IOException {
             () ->
                 add(
                     "not-tolerant",
-                    null,
+                    SolrParams.of(),
                     Arrays.asList(new SolrInputDocument[] {invalidDoc1, validDoc1})));
     assertTrue(e.getMessage().contains("Document is missing mandatory uniqueKey field"));
 
@@ -159,7 +159,7 @@ public void testInvalidAdds() throws IOException {
     assertAddsSucceedWithErrors(
         "tolerant-chain-max-errors-10",
         Arrays.asList(new SolrInputDocument[] {invalidDoc1, validDoc1}),
-        null,
+        SolrParams.of(),
         "(unknown)");
     assertU(commit());
 
@@ -176,7 +176,7 @@ public void testInvalidAdds() throws IOException {
             () ->
                 add(
                     "not-tolerant",
-                    null,
+                    SolrParams.of(),
                     Arrays.asList(new SolrInputDocument[] {invalidDoc2, validDoc2})));
     assertTrue(e.getMessage().contains("Error adding field"));
 
@@ -186,7 +186,7 @@ public void testInvalidAdds() throws IOException {
     assertAddsSucceedWithErrors(
         "tolerant-chain-max-errors-10",
         Arrays.asList(new SolrInputDocument[] {invalidDoc2, validDoc2}),
-        null,
+        SolrParams.of(),
         "2");
     assertU(commit());
 
@@ -201,7 +201,7 @@ public void testInvalidAdds() throws IOException {
   public void testMaxErrorsDefault() throws IOException {
     // by default the TolerantUpdateProcessor accepts all errors, so this batch should succeed with
     // 10 errors.
-    assertAddsSucceedWithErrors("tolerant-chain-max-errors-not-set", docs, null, badIds);
+    assertAddsSucceedWithErrors("tolerant-chain-max-errors-not-set", docs, SolrParams.of(), badIds);
     assertU(commit());
     assertQ(req("q", "*:*"), "//result[@numFound='10']");
   }
@@ -240,7 +240,7 @@ public void testMaxErrorsThrowsException() {
   public void testMaxErrorsInfinite() throws IOException {
     ModifiableSolrParams requestParams = new ModifiableSolrParams();
     requestParams.add("maxErrors", "-1");
-    assertAddsSucceedWithErrors("tolerant-chain-max-errors-not-set", docs, null, badIds);
+    assertAddsSucceedWithErrors("tolerant-chain-max-errors-not-set", docs, SolrParams.of(), badIds);
 
     assertU(commit());
     assertQ(req("q", "*:*"), "//result[@numFound='10']");
@@ -421,7 +421,7 @@ private void assertAddsSucceedWithErrors(
 
   protected SolrQueryResponse add(final String chain, final SolrInputDocument doc)
       throws IOException {
-    return add(chain, null, Arrays.asList(new SolrInputDocument[] {doc}));
+    return add(chain, SolrParams.of(), Arrays.asList(new SolrInputDocument[] {doc}));
   }
 
   protected SolrQueryResponse add(
@@ -435,10 +435,6 @@ protected SolrQueryResponse add(
     SolrQueryResponse rsp = new SolrQueryResponse();
     rsp.add("responseHeader", new SimpleOrderedMap<>());
 
-    if (requestParams == null) {
-      requestParams = new ModifiableSolrParams();
-    }
-
     SolrQueryRequest req = new LocalSolrQueryRequest(core, requestParams);
     UpdateRequestProcessor processor = null;
     try {

solr/cross-dc-manager/src/java/org/apache/solr/crossdc/manager/messageprocessor/SolrMessageProcessor.java

@@ -331,7 +331,8 @@ void preventCircularMirroring(MirroredSolrRequest<?> mirroredSolrRequest) {
       }
     } else {
       SolrParams params = mirroredSolrRequest.getSolrRequest().getParams();
-      String shouldMirror = (params == null ? null : params.get(CrossDcConstants.SHOULD_MIRROR));
+      assert params != null;
+      String shouldMirror = params.get(CrossDcConstants.SHOULD_MIRROR);
       if (shouldMirror == null) {
         if (params instanceof ModifiableSolrParams) {
           log.warn("{} param is missing - setting to false", CrossDcConstants.SHOULD_MIRROR);

solr/cross-dc-manager/src/test/org/apache/solr/crossdc/manager/consumer/KafkaCrossDcConsumerTest.java

@@ -52,7 +52,6 @@
 import org.apache.solr.client.solrj.request.CollectionAdminRequest;
 import org.apache.solr.client.solrj.request.UpdateRequest;
 import org.apache.solr.common.SolrInputDocument;
-import org.apache.solr.common.params.ModifiableSolrParams;
 import org.apache.solr.common.util.ExecutorUtil;
 import org.apache.solr.common.util.SolrNamedThreadFactory;
 import org.apache.solr.common.util.Utils;
@@ -279,7 +278,7 @@ public void testHandleValidMirroredSolrRequest() {
     doc.addField("id", "1");
     UpdateRequest validRequest = new UpdateRequest();
     validRequest.add(doc);
-    validRequest.setParams(new ModifiableSolrParams().add("commit", "true"));
+    validRequest.getParams().set("commit", true);
     // Create a valid MirroredSolrRequest
     ConsumerRecord<String, MirroredSolrRequest<?>> record =
         new ConsumerRecord<>("test-topic", 0, 0, "key", new MirroredSolrRequest<>(validRequest));
@@ -459,7 +458,7 @@ protected KafkaMirroringSink createKafkaMirroringSink(KafkaCrossDcConf conf) {
 
     UpdateRequest invalidRequest = new UpdateRequest();
     // no updates on request
-    invalidRequest.setParams(new ModifiableSolrParams().add("invalid_param", "invalid_value"));
+    invalidRequest.getParams().add("invalid_param", "invalid_value");
 
     ConsumerRecord<String, MirroredSolrRequest<?>> record =
         new ConsumerRecord<>("test-topic", 0, 0, "key", new MirroredSolrRequest<>(invalidRequest));