Fix error in RemoteSegmentStoreDirectory when debug logging is enabled

CHANGELOG.md

@@ -87,6 +87,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Update supported version for must_exist parameter in update aliases API ([#11872](https://github.com/opensearch-project/OpenSearch/pull/11872))
 - [Bug] Check phase name before SearchRequestOperationsListener onPhaseStart ([#12035](https://github.com/opensearch-project/OpenSearch/pull/12035))
 - Fix Span operation names generated from RestActions ([#12005](https://github.com/opensearch-project/OpenSearch/pull/12005))
+- Fix error in RemoteSegmentStoreDirectory when debug logging is enabled ([#12328](https://github.com/opensearch-project/OpenSearch/pull/12328))
 
 ### Security
 

server/src/main/java/org/opensearch/index/store/RemoteSegmentStoreDirectory.java

@@ -45,6 +45,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.file.NoSuchFileException;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -745,9 +746,8 @@ public void deleteStaleSegments(int lastNMetadataFilesToKeep) throws IOException
             return;
         }
 
-        List<String> metadataFilesEligibleToDelete = sortedMetadataFileList.subList(
-            lastNMetadataFilesToKeep,
-            sortedMetadataFileList.size()
+        List<String> metadataFilesEligibleToDelete = new ArrayList<>(
+            sortedMetadataFileList.subList(lastNMetadataFilesToKeep, sortedMetadataFileList.size())
         );
         Set<String> allLockFiles;
         try {
@@ -764,7 +764,7 @@ public void deleteStaleSegments(int lastNMetadataFilesToKeep) throws IOException
         logger.debug(
             "metadataFilesEligibleToDelete={} metadataFilesToBeDeleted={}",
             metadataFilesEligibleToDelete,
-            metadataFilesEligibleToDelete
+            metadataFilesToBeDeleted
         );
 
         Map<String, UploadedSegmentMetadata> activeSegmentFilesMetadataMap = new HashMap<>();

test/framework/src/main/java/org/opensearch/test/OpenSearchTestCase.java

@@ -145,6 +145,8 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.PrintWriter;
+import java.io.StringWriter;
 import java.math.BigInteger;
 import java.net.InetAddress;
 import java.net.UnknownHostException;
@@ -170,6 +172,7 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.BooleanSupplier;
 import java.util.function.Consumer;
+import java.util.function.Function;
 import java.util.function.IntFunction;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
@@ -639,7 +642,32 @@ protected static void checkStaticState(boolean afterClass) throws Exception {
             try {
                 // ensure that there are no status logger messages which would indicate a problem with our Log4j usage; we map the
                 // StatusData instances to Strings as otherwise their toString output is useless
+
+                final Function<StatusData, String> statusToString = (statusData) -> {
+                    try (final StringWriter sw = new StringWriter(); final PrintWriter pw = new PrintWriter(sw)) {
+
+                        pw.print(statusData.getLevel());
+                        pw.print(":");
+                        pw.print(statusData.getMessage().getFormattedMessage());
+
+                        if (statusData.getStackTraceElement() != null) {
+                            final var messageSource = statusData.getStackTraceElement();
+                            pw.println("Source:");
+                            pw.println(messageSource.getFileName() + "@" + messageSource.getLineNumber());
+                        }
+
+                        if (statusData.getThrowable() != null) {
+                            pw.println("Throwable:");
+                            statusData.getThrowable().printStackTrace(pw);
+                        }
+                        return sw.toString();
+                    } catch (IOException ioe) {
+                        throw new RuntimeException(ioe);
+                    }
+                };
+
                 assertThat(
+                    statusData.stream().map(statusToString::apply).collect(Collectors.joining("\r\n")),
                     statusData.stream().map(status -> status.getMessage().getFormattedMessage()).collect(Collectors.toList()),
                     empty()
                 );