Core: Fix metadata table uuid to return a consistent UUID for the sam…

…e reference (apache#9310)

core/src/main/java/org/apache/iceberg/BaseMetadataTable.java

@@ -44,13 +44,15 @@ public abstract class BaseMetadataTable extends BaseReadOnlyTable
   private final SortOrder sortOrder = SortOrder.unsorted();
   private final BaseTable table;
   private final String name;
+  private final UUID uuid;
 
   protected BaseMetadataTable(Table table, String name) {
     super("metadata");
     Preconditions.checkArgument(
         table instanceof BaseTable, "Cannot create metadata table for non-data table: %s", table);
     this.table = (BaseTable) table;
     this.name = name;
+    this.uuid = UUID.randomUUID();
   }
 
   /**
@@ -202,7 +204,7 @@ public Map<String, SnapshotRef> refs() {
 
   @Override
   public UUID uuid() {
-    return UUID.randomUUID();
+    return uuid;
   }
 
   @Override

core/src/test/java/org/apache/iceberg/TestMetadataTableScans.java

@@ -43,6 +43,7 @@
 import org.apache.iceberg.relocated.com.google.common.collect.Streams;
 import org.apache.iceberg.types.Types;
 import org.apache.iceberg.util.StructLikeWrapper;
+import org.assertj.core.api.Assertions;
 import org.junit.Assert;
 import org.junit.Assume;
 import org.junit.Test;
@@ -138,6 +139,18 @@ public void testManifestsTableAlwaysIgnoresResiduals() throws IOException {
     }
   }
 
+  @Test
+  public void testMetadataTableUUID() {
+    Table manifestsTable = new ManifestsTable(table);
+
+    Assertions.assertThat(manifestsTable.uuid())
+        .as("UUID should be consistent on multiple calls")
+        .isEqualTo(manifestsTable.uuid());
+    Assertions.assertThat(manifestsTable.uuid())
+        .as("Metadata table UUID should be different from the base table UUID")
+        .isNotEqualTo(table.uuid());
+  }
+
   @Test
   public void testDataFilesTableWithDroppedPartition() throws IOException {
     table.newFastAppend().appendFile(FILE_A).appendFile(FILE_B).commit();