Add temporary logging for #125668 (#125749)

This failure doesn't reproduce locally after repeated attempts. Unmuting
it in CI with some additional logging, to be reverted ASAP.

Author: DaveCTurner

muted-tests.yml

@@ -378,9 +378,6 @@ tests:
 - class: org.elasticsearch.smoketest.MlWithSecurityIT
   method: test {yaml=ml/data_frame_analytics_cat_apis/Test cat data frame analytics single job with header}
   issue: https://github.com/elastic/elasticsearch/issues/125642
-- class: org.elasticsearch.repositories.blobstore.testkit.analyze.GCSRepositoryAnalysisRestIT
-  method: testRepositoryAnalysis
-  issue: https://github.com/elastic/elasticsearch/issues/125668
 - class: org.elasticsearch.packaging.test.DockerTests
   method: test010Install
   issue: https://github.com/elastic/elasticsearch/issues/125680

server/src/main/java/org/elasticsearch/common/blobstore/support/BlobContainerUtils.java

@@ -9,10 +9,16 @@
 
 package org.elasticsearch.common.blobstore.support;
 
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.elasticsearch.common.ReferenceDocs;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.blobstore.BlobContainer;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.logging.ChunkedLoggingStream;
+import org.elasticsearch.common.unit.ByteSizeUnit;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -32,6 +38,8 @@ public static void ensureValidRegisterContent(BytesReference bytesReference) {
         }
     }
 
+    private static final Logger logger = LogManager.getLogger(BlobContainerUtils.class);
+
     /**
      * Many blob stores have consistent (linearizable/atomic) read semantics and in these casees it is safe to implement {@link
      * BlobContainer#getRegister} by simply reading the blob using this utility.
@@ -51,7 +59,28 @@ public static BytesReference getRegisterUsingConsistentRead(InputStream inputStr
             len -= read;
             pos += read;
         }
-        if (inputStream.read() != -1) {
+        final int nextByte = inputStream.read();
+        if (nextByte != -1) {
+            try (
+                var cls = ChunkedLoggingStream.create(
+                    logger,
+                    Level.ERROR,
+                    "getRegisterUsingConsistentRead including trailing data",
+                    ReferenceDocs.LOGGING
+                )
+            ) {
+                cls.write(bytes);
+                cls.write(nextByte);
+                final var buffer = new byte[ByteSizeUnit.KB.toIntBytes(1)];
+                while (true) {
+                    final var readSize = inputStream.read(buffer);
+                    if (readSize == -1) {
+                        break;
+                    }
+                    cls.write(buffer, 0, readSize);
+                }
+            }
+
             throw new IllegalStateException(
                 Strings.format("[%s] failed reading register [%s] due to unexpected trailing data", container, key)
             );