From 24578a28fe69db96da460ac49eeb1a60fee7b8c7 Mon Sep 17 00:00:00 2001
From: Ajantha Bhat <ajanthabhat@gmail.com>
Date: Sun, 17 Dec 2023 00:18:55 +0530
Subject: [PATCH] Core: Fix metadata table uuid to return a consistent UUID for
 the same reference (#9310)

---
 .../java/org/apache/iceberg/BaseMetadataTable.java  |  4 +++-
 .../org/apache/iceberg/TestMetadataTableScans.java  | 13 +++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/core/src/main/java/org/apache/iceberg/BaseMetadataTable.java b/core/src/main/java/org/apache/iceberg/BaseMetadataTable.java
index 124115496b3e..4565b898c43d 100644
--- a/core/src/main/java/org/apache/iceberg/BaseMetadataTable.java
+++ b/core/src/main/java/org/apache/iceberg/BaseMetadataTable.java
@@ -44,6 +44,7 @@ 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");
@@ -51,6 +52,7 @@ protected BaseMetadataTable(Table table, String name) {
         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
diff --git a/core/src/test/java/org/apache/iceberg/TestMetadataTableScans.java b/core/src/test/java/org/apache/iceberg/TestMetadataTableScans.java
index 9da1838ad2e4..aa1da6b182dc 100644
--- a/core/src/test/java/org/apache/iceberg/TestMetadataTableScans.java
+++ b/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();