Fix bwc again

Author: nicktindall

server/src/main/java/org/elasticsearch/rest/action/cat/RestThreadPoolAction.java

@@ -226,7 +226,9 @@ private Table buildTable(RestRequest req, ClusterStateResponse state, NodesInfoR
                 }
 
                 table.addCell(entry.getKey());
-                table.addCell(poolInfo == null ? null : ThreadPool.ThreadPoolType.bwcType(poolInfo.getName()));
+                table.addCell(
+                    poolInfo == null ? null : ThreadPool.ThreadPoolType.bwcType(poolInfo.getName(), poolInfo.getThreadPoolType())
+                );
                 table.addCell(poolStats == null ? null : poolStats.active());
                 table.addCell(poolStats == null ? null : poolStats.threads());
                 table.addCell(poolStats == null ? null : poolStats.queue());

server/src/main/java/org/elasticsearch/threadpool/ThreadPool.java

@@ -184,15 +184,15 @@ public static ThreadPoolType fromType(String type) {
             return threadPoolType;
         }
 
-        public static ThreadPoolType bwcType(String threadPoolName) {
+        public static ThreadPoolType bwcType(String threadPoolName, ThreadPoolType defaultType) {
             switch (threadPoolName) {
                 case Names.WRITE:
                 case Names.WRITE_COORDINATION:
                     return FIXED;
                 case Names.GENERIC:
                     return SCALING;
                 default:
-                    return THREAD_POOL_TYPES.get(threadPoolName);
+                    return defaultType;
             }
         }
     }
@@ -999,7 +999,7 @@ public void writeTo(StreamOutput out) throws IOException {
             if (out.getTransportVersion().onOrAfter(TransportVersions.VIRTUAL_THREADS)) {
                 out.writeString(type.getType());
             } else {
-                out.writeString(ThreadPoolType.bwcType(name).getType());
+                out.writeString(ThreadPoolType.bwcType(name, type).getType());
             }
             out.writeInt(min);
             out.writeInt(max);