Resolve various backporting issues

1. Can't reference version 3.0.0.
2. Bad merges of adjacent version checks.
3. Use of Apache HTTP client 4 (vs 5).
4. Use of old cluster manager naming in REST params.
5. CollectionUtils didn't have isEmpty for collections.

Signed-off-by: Michael Froh <froh@amazon.com>

client/rest-high-level/src/main/java/org/opensearch/client/SearchPipelineRequestConverters.java

@@ -8,9 +8,9 @@
 
 package org.opensearch.client;
 
-import org.apache.hc.client5.http.classic.methods.HttpDelete;
-import org.apache.hc.client5.http.classic.methods.HttpGet;
-import org.apache.hc.client5.http.classic.methods.HttpPut;
+import org.apache.http.client.methods.HttpDelete;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpPut;
 import org.opensearch.action.search.DeleteSearchPipelineRequest;
 import org.opensearch.action.search.GetSearchPipelineRequest;
 import org.opensearch.action.search.PutSearchPipelineRequest;
@@ -28,7 +28,7 @@ static Request putPipeline(PutSearchPipelineRequest putPipelineRequest) throws I
 
         RequestConverters.Params params = new RequestConverters.Params();
         params.withTimeout(putPipelineRequest.timeout());
-        params.withClusterManagerTimeout(putPipelineRequest.clusterManagerNodeTimeout());
+        params.withMasterTimeout(putPipelineRequest.clusterManagerNodeTimeout());
         request.addParameters(params.asMap());
         request.setEntity(RequestConverters.createEntity(putPipelineRequest, RequestConverters.REQUEST_BODY_CONTENT_TYPE));
         return request;
@@ -42,7 +42,7 @@ static Request deletePipeline(DeleteSearchPipelineRequest deletePipelineRequest)
 
         RequestConverters.Params parameters = new RequestConverters.Params();
         parameters.withTimeout(deletePipelineRequest.timeout());
-        parameters.withClusterManagerTimeout(deletePipelineRequest.clusterManagerNodeTimeout());
+        parameters.withMasterTimeout(deletePipelineRequest.clusterManagerNodeTimeout());
         request.addParameters(parameters.asMap());
         return request;
     }
@@ -54,7 +54,7 @@ static Request getPipeline(GetSearchPipelineRequest getPipelineRequest) {
         Request request = new Request(HttpGet.METHOD_NAME, endpoint);
 
         RequestConverters.Params parameters = new RequestConverters.Params();
-        parameters.withClusterManagerTimeout(getPipelineRequest.clusterManagerNodeTimeout());
+        parameters.withMasterTimeout(getPipelineRequest.clusterManagerNodeTimeout());
         request.addParameters(parameters.asMap());
         return request;
     }

server/src/main/java/org/opensearch/OpenSearchException.java

@@ -78,6 +78,7 @@
 import static org.opensearch.Version.V_2_4_0;
 import static org.opensearch.Version.V_2_5_0;
 import static org.opensearch.Version.V_2_6_0;
+import static org.opensearch.Version.V_2_7_0;
 import static org.opensearch.cluster.metadata.IndexMetadata.INDEX_UUID_NA_VALUE;
 import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.common.xcontent.XContentParserUtils.ensureFieldName;
@@ -1658,12 +1659,7 @@ private enum OpenSearchExceptionHandle {
             V_2_6_0
         ),
         NODE_WEIGHED_AWAY_EXCEPTION(NodeWeighedAwayException.class, NodeWeighedAwayException::new, 169, V_2_6_0),
-        SEARCH_PIPELINE_PROCESSING_EXCEPTION(
-            SearchPipelineProcessingException.class,
-            SearchPipelineProcessingException::new,
-            170,
-            V_3_0_0 // TODO: Update if/when we backport to 2.x
-        ),
+        SEARCH_PIPELINE_PROCESSING_EXCEPTION(SearchPipelineProcessingException.class, SearchPipelineProcessingException::new, 170, V_2_7_0),
         INDEX_CREATE_BLOCK_EXCEPTION(
             org.opensearch.cluster.block.IndexCreateBlockException.class,
             org.opensearch.cluster.block.IndexCreateBlockException::new,

server/src/main/java/org/opensearch/action/admin/cluster/node/info/NodeInfo.java

@@ -102,9 +102,9 @@ public NodeInfo(StreamInput in) throws IOException {
         addInfoIfNonNull(IngestInfo.class, in.readOptionalWriteable(IngestInfo::new));
         if (in.getVersion().onOrAfter(LegacyESVersion.V_7_10_0)) {
             addInfoIfNonNull(AggregationInfo.class, in.readOptionalWriteable(AggregationInfo::new));
-        if (in.getVersion().onOrAfter(Version.V_3_0_0)) { // TODO: Change if/when we backport to 2.x
-            addInfoIfNonNull(SearchPipelineInfo.class, in.readOptionalWriteable(SearchPipelineInfo::new));
         }
+        if (in.getVersion().onOrAfter(Version.V_2_7_0)) {
+            addInfoIfNonNull(SearchPipelineInfo.class, in.readOptionalWriteable(SearchPipelineInfo::new));
         }
     }
 
@@ -232,10 +232,11 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeOptionalWriteable(getInfo(IngestInfo.class));
         if (out.getVersion().onOrAfter(LegacyESVersion.V_7_10_0)) {
             out.writeOptionalWriteable(getInfo(AggregationInfo.class));
-        if (out.getVersion().onOrAfter(Version.V_3_0_0)) { // TODO: Change if/when we backport to 2.x
-            out.writeOptionalWriteable(getInfo(SearchPipelineInfo.class));
         }
+        if (out.getVersion().onOrAfter(Version.V_2_7_0)) {
+            out.writeOptionalWriteable(getInfo(SearchPipelineInfo.class));
         }
+    }
 
     public static NodeInfo.Builder builder(Version version, Build build, DiscoveryNode node) {
         return new Builder(version, build, node);
@@ -349,6 +350,4 @@ public NodeInfo build() {
         }
 
     }
-
-    }
 }

server/src/main/java/org/opensearch/action/search/SearchRequest.java

@@ -259,9 +259,9 @@ public SearchRequest(StreamInput in) throws IOException {
 
         if (in.getVersion().onOrAfter(Version.V_1_1_0)) {
             cancelAfterTimeInterval = in.readOptionalTimeValue();
-        if (in.getVersion().onOrAfter(Version.V_3_0_0)) { // TODO: Update if/when we backport to 2.x
-            pipeline = in.readOptionalString();
         }
+        if (in.getVersion().onOrAfter(Version.V_2_7_0)) {
+            pipeline = in.readOptionalString();
         }
     }
 
@@ -299,9 +299,9 @@ public void writeTo(StreamOutput out) throws IOException {
 
         if (out.getVersion().onOrAfter(Version.V_1_1_0)) {
             out.writeOptionalTimeValue(cancelAfterTimeInterval);
-        if (out.getVersion().onOrAfter(Version.V_3_0_0)) { // TODO: Update if/when we backport to 2.x
-            out.writeOptionalString(pipeline);
         }
+        if (out.getVersion().onOrAfter(Version.V_2_7_0)) {
+            out.writeOptionalString(pipeline);
         }
     }
 

server/src/main/java/org/opensearch/common/util/CollectionUtils.java

@@ -353,4 +353,16 @@ public static <E> List<List<E>> eagerPartition(List<E> list, int size) {
 
         return result;
     }
+
+    /**
+     * Check if a collection is empty or not. Empty collection mean either it is null or it has no elements in it. If
+     * collection contains a null element it means it is not empty.
+     *
+     * @param collection {@link Collection}
+     * @return boolean
+     * @param <E> Element
+     */
+    public static <E> boolean isEmpty(final Collection<E> collection) {
+        return collection == null || collection.isEmpty();
+    }
 }