From 08025dda7bd3daff8d2a34a7083a4ec4f62bb83b Mon Sep 17 00:00:00 2001
From: yuzelin <33053040+yuzelin@users.noreply.github.com>
Date: Sun, 7 Apr 2024 13:57:05 +0800
Subject: [PATCH] [core] BranchManager lists branches in the order of create
 time (#3155)

---
 .../java/org/apache/paimon/utils/BranchManager.java  | 12 +++++++++---
 .../apache/paimon/table/system/TagsTableTest.java    |  2 +-
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/paimon-core/src/main/java/org/apache/paimon/utils/BranchManager.java b/paimon-core/src/main/java/org/apache/paimon/utils/BranchManager.java
index 6564bd4e56dc..95034e05a6f4 100644
--- a/paimon-core/src/main/java/org/apache/paimon/utils/BranchManager.java
+++ b/paimon-core/src/main/java/org/apache/paimon/utils/BranchManager.java
@@ -31,7 +31,9 @@
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Comparator;
 import java.util.List;
+import java.util.PriorityQueue;
 import java.util.SortedMap;
 import java.util.stream.Collectors;
 
@@ -164,7 +166,8 @@ public List<TableBranch> branches() {
                     listVersionedFileStatus(fileIO, branchDirectory(), BRANCH_PREFIX)
                             .map(status -> Pair.of(status.getPath(), status.getModificationTime()))
                             .collect(Collectors.toList());
-            List<TableBranch> branches = new ArrayList<>();
+            PriorityQueue<TableBranch> pq =
+                    new PriorityQueue<>(Comparator.comparingLong(TableBranch::getCreateTime));
             for (Pair<Path, Long> path : paths) {
                 String branchName = path.getLeft().getName().substring(BRANCH_PREFIX.length());
                 FileStoreTable branchTable =
@@ -175,10 +178,13 @@ public List<TableBranch> branches() {
                 Snapshot snapshot = snapshotTags.firstKey();
                 List<String> tags = snapshotTags.get(snapshot);
                 checkArgument(tags.size() == 1);
-                branches.add(
-                        new TableBranch(branchName, tags.get(0), snapshot.id(), path.getValue()));
+                pq.add(new TableBranch(branchName, tags.get(0), snapshot.id(), path.getValue()));
             }
 
+            List<TableBranch> branches = new ArrayList<>(pq.size());
+            while (!pq.isEmpty()) {
+                branches.add(pq.poll());
+            }
             return branches;
         } catch (IOException e) {
             throw new RuntimeException(e);
diff --git a/paimon-core/src/test/java/org/apache/paimon/table/system/TagsTableTest.java b/paimon-core/src/test/java/org/apache/paimon/table/system/TagsTableTest.java
index c754aa779aa2..97beecd4de42 100644
--- a/paimon-core/src/test/java/org/apache/paimon/table/system/TagsTableTest.java
+++ b/paimon-core/src/test/java/org/apache/paimon/table/system/TagsTableTest.java
@@ -110,7 +110,7 @@ void testTagBranchesTable() throws Exception {
                             if (tag.equals("2023-07-17")) {
                                 return Collections.singletonList("2023-07-17-branch1");
                             } else if (tag.equals("2023-07-18")) {
-                                return Arrays.asList("2023-07-18-branch2", "2023-07-18-branch1");
+                                return Arrays.asList("2023-07-18-branch1", "2023-07-18-branch2");
                             } else {
                                 return new ArrayList<>();
                             }