From c296180aa0bce3e07da99ae9dcc19e160580042f Mon Sep 17 00:00:00 2001
From: "hanyu.liang" <hanyu.liang@zstack.io>
Date: Fri, 3 Jul 2026 16:27:42 +0800
Subject: [PATCH] <fix>[zone]: set first created zone as default

When isDefault is omitted, zone creation now enters the
default-zone queue. If no zone exists, the new zone becomes
default before persistence.

Backfill one default zone during 5.5.28 upgrade for deployments
where zones already exist but none is marked default.

DBImpact

Test: ZoneCase
Test: SQL backfill on scratch schema

Resolves: ZSTAC-75952

Change-Id: Ia4844f7a37d823508d16a74f06ec2333f50b4d07
---
 .../zstack/compute/zone/ZoneManagerImpl.java  |  6 +++-
 conf/db/upgrade/V5.5.28__schema.sql           | 32 +++++++++++++++++++
 .../test/integration/compute/ZoneCase.groovy  | 30 +++++++++++++----
 3 files changed, 61 insertions(+), 7 deletions(-)

diff --git a/compute/src/main/java/org/zstack/compute/zone/ZoneManagerImpl.java b/compute/src/main/java/org/zstack/compute/zone/ZoneManagerImpl.java
index 1537ed30318..e806761229d 100755
--- a/compute/src/main/java/org/zstack/compute/zone/ZoneManagerImpl.java
+++ b/compute/src/main/java/org/zstack/compute/zone/ZoneManagerImpl.java
@@ -152,6 +152,10 @@ private ZoneInventory createZoneFromApiMessage(APICreateZoneMsg msg) {
         new SQLBatch() {
             @Override
             protected void scripts() {
+                if (msg.getDefault() == null && !q(ZoneVO.class).isExists()) {
+                    finalVO.setDefault(true);
+                }
+
                 if (finalVO.isDefault()) {
                     sql(ZoneVO.class)
                             .set(ZoneVO_.isDefault, false)
@@ -181,7 +185,7 @@ private void createDefaultManagementNetworkIpVersionTagIfAbsent(String zoneUuid)
     }
 
     private void createZone(APICreateZoneMsg msg, ReturnValueCompletion<ZoneInventory> completion) {
-        if (msg.getDefault() == null || !msg.getDefault()) {
+        if (msg.getDefault() != null && !msg.getDefault()) {
             completion.success(createZoneFromApiMessage(msg));
             return;
         }
diff --git a/conf/db/upgrade/V5.5.28__schema.sql b/conf/db/upgrade/V5.5.28__schema.sql
index b30064a2a08..cc96f27fdf0 100644
--- a/conf/db/upgrade/V5.5.28__schema.sql
+++ b/conf/db/upgrade/V5.5.28__schema.sql
@@ -199,6 +199,38 @@ WHERE NOT EXISTS (
       AND st.tag LIKE 'managementNetwork::ipVersion::%'
 );
 
+-- ZSTAC-75952: backfill one default zone for deployments affected by zone creation without isDefault.
+DROP PROCEDURE IF EXISTS backfill_default_zone_if_absent;
+DELIMITER $$
+CREATE PROCEDURE backfill_default_zone_if_absent()
+BEGIN
+    DECLARE default_zone_count BIGINT DEFAULT 0;
+    DECLARE first_zone_uuid VARCHAR(32) DEFAULT NULL;
+
+    SELECT COUNT(*) INTO default_zone_count
+    FROM `zstack`.`ZoneVO`
+    WHERE `isDefault` = 1;
+
+    IF default_zone_count = 0 THEN
+        SET first_zone_uuid = (
+            SELECT `uuid`
+            FROM `zstack`.`ZoneVO`
+            ORDER BY `createDate` ASC, `uuid` ASC
+            LIMIT 1
+        );
+
+        IF first_zone_uuid IS NOT NULL THEN
+            UPDATE `zstack`.`ZoneEO`
+            SET `isDefault` = 1
+            WHERE `uuid` = first_zone_uuid;
+        END IF;
+    END IF;
+END $$
+DELIMITER ;
+
+CALL backfill_default_zone_if_absent();
+DROP PROCEDURE IF EXISTS backfill_default_zone_if_absent;
+
 ALTER TABLE `zstack`.`ConsoleProxyAgentVO` ADD COLUMN `consoleProxyOverriddenIpv4` varchar(255) DEFAULT NULL;
 ALTER TABLE `zstack`.`ConsoleProxyAgentVO` ADD COLUMN `consoleProxyOverriddenIpv6` varchar(255) DEFAULT NULL;
 
diff --git a/test/src/test/groovy/org/zstack/test/integration/compute/ZoneCase.groovy b/test/src/test/groovy/org/zstack/test/integration/compute/ZoneCase.groovy
index 67e86160548..c8a864c8c41 100644
--- a/test/src/test/groovy/org/zstack/test/integration/compute/ZoneCase.groovy
+++ b/test/src/test/groovy/org/zstack/test/integration/compute/ZoneCase.groovy
@@ -10,12 +10,13 @@ import org.zstack.testlib.EnvSpec
 import org.zstack.testlib.SubCase
 
 /**
- * 1. test create zone as default zone
- * 2. test batch create zone as default zone
- * 3. test update zone to default zone
- * 4. test batch update zone to default zone
- * 5. test query default zone
- * 6. test delete default zone
+ * 1. test first created zone defaults to default zone
+ * 2. test create zone as default zone
+ * 3. test batch create zone as default zone
+ * 4. test update zone to default zone
+ * 5. test batch update zone to default zone
+ * 6. test query default zone
+ * 7. test delete default zone
  */
 class ZoneCase extends SubCase {
     EnvSpec env
@@ -33,6 +34,7 @@ class ZoneCase extends SubCase {
     @Override
     void test() {
         env.create {
+            testFirstCreatedZoneDefaultsToDefaultZone()
             testCreateZoneAsDefaultZone()
             testBatchCreateZoneAsDefaultZone()
             testUpdateZoneToDefaultZone()
@@ -48,6 +50,22 @@ class ZoneCase extends SubCase {
         env.delete()
     }
 
+    void testFirstCreatedZoneDefaultsToDefaultZone() {
+        ZoneInventory zone = createZone {
+            name = "first-zone"
+            description = "first-zone"
+        } as ZoneInventory
+
+        assert zone.isDefault
+        assert Q.New(ZoneVO.class)
+                .eq(ZoneVO_.uuid, zone.uuid)
+                .eq(ZoneVO_.isDefault, true)
+                .isExists()
+        assert Q.New(ZoneVO.class)
+                .eq(ZoneVO_.isDefault, true)
+                .count() == 1
+    }
+
     void testCreateZoneAsDefaultZone() {
         ZoneInventory zone = createZone {
             name = "zone1"