From 8f26c3f182c7f1dbd0b3adfd3d7e486c9d32791b Mon Sep 17 00:00:00 2001
From: WhaleTech <304937387+ryo-whaletech@users.noreply.github.com>
Date: Fri, 11 Sep 2026 15:39:47 +0900
Subject: [PATCH] {Compute} Fix VMSS zone placement filter switching

---
 .../azure/cli/command_modules/vm/custom.py    |  2 ++
 .../tests/latest/test_custom_vm_commands.py   | 33 ++++++++++++++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/azure-cli/azure/cli/command_modules/vm/custom.py b/src/azure-cli/azure/cli/command_modules/vm/custom.py
index 131be9743ca..72eb4025978 100644
--- a/src/azure-cli/azure/cli/command_modules/vm/custom.py
+++ b/src/azure-cli/azure/cli/command_modules/vm/custom.py
@@ -5150,9 +5150,11 @@ def _output(self, *args, **kwargs):
 
         if include_zones is not None:
             vmss["placement"]["include_zones"] = include_zones
+            vmss["placement"].pop("exclude_zones", None)
 
         if exclude_zones is not None:
             vmss["placement"]["exclude_zones"] = exclude_zones
+            vmss["placement"].pop("include_zones", None)
 
     from .operations.vmss import VMSSCreate
     return VMSSCreate(cli_ctx=cmd.cli_ctx)(command_args=vmss)
diff --git a/src/azure-cli/azure/cli/command_modules/vm/tests/latest/test_custom_vm_commands.py b/src/azure-cli/azure/cli/command_modules/vm/tests/latest/test_custom_vm_commands.py
index 4ab2527a4aa..5114da33de3 100644
--- a/src/azure-cli/azure/cli/command_modules/vm/tests/latest/test_custom_vm_commands.py
+++ b/src/azure-cli/azure/cli/command_modules/vm/tests/latest/test_custom_vm_commands.py
@@ -16,7 +16,7 @@
                                                  _get_extension_instance_name,
                                                  get_boot_log)
 from azure.cli.command_modules.vm.custom import \
-    (attach_unmanaged_data_disk, detach_unmanaged_data_disk, get_vmss_instance_view)
+    (attach_unmanaged_data_disk, detach_unmanaged_data_disk, get_vmss_instance_view, update_vmss)
 
 from azure.cli.core import AzCommandsLoader
 from azure.cli.core.commands import AzCliCommand
@@ -166,6 +166,37 @@ def test_get_extension_instance_name_when_type_none(self):
         # assert
         self.assertEqual(result, 'extension-name')
 
+    @mock.patch('azure.cli.command_modules.vm.operations.vmss.VMSSCreate')
+    def test_update_vmss_switches_zone_placement_filter(self, vmss_create_mock):
+        transitions = (
+            ('includeZones', ['1'], 'exclude_zones', ['2'], 'include_zones'),
+            ('excludeZones', ['2'], 'include_zones', ['1'], 'exclude_zones'),
+        )
+
+        for existing_key, existing_value, new_key, new_value, stale_key in transitions:
+            with self.subTest(existing_key=existing_key, new_key=new_key):
+                vmss_create_mock.reset_mock()
+                parameters = {
+                    'location': 'eastus2',
+                    'placement': {
+                        'zonePlacementPolicy': 'Auto',
+                        existing_key: existing_value,
+                    },
+                }
+
+                update_vmss(
+                    _get_test_cmd(),
+                    'resource-group',
+                    'vmss-name',
+                    parameters=parameters,
+                    **{new_key: new_value}
+                )
+
+                command_args = vmss_create_mock.return_value.call_args.kwargs['command_args']
+                placement = command_args['placement']
+                self.assertEqual(new_value, placement[new_key])
+                self.assertNotIn(stale_key, placement)
+
 
 class TestVMBootLog(unittest.TestCase):