fix Remove-AzVmss bug (Azure#21284)

* update

* Update ChangeLog.md

---------

Co-authored-by: Theodore Chang <[email protected]>
Co-authored-by: Yabo Hu <[email protected]>

Author: 3 people

src/Compute/Compute/ChangeLog.md

@@ -23,9 +23,7 @@
 * Removed the image alias `CoreOS` as the publisher CoreOS no longer has any images for Azure. 
 * Updated the names of the `openSUSE-Leap` and `SLES` aliases to `OpenSuseLeap154` and `SuseSles15SP4` respectively. Updated these aliases to point to an image that actually exists and updated the alias names to be descriptive and versioned.
 * Added new descriptive and versioned alias names for the Linux image aliases.
-* Added `-NetworkAccessPolicy` parameter to `New-AzSnapshotUpdateConfig`.
-* Added `-SharedGalleryImageId` parameter to `New-AzVM`, `New-AzVmConfig`, `New-AzVmss`, `New-AzVmssConfig`, `Update-AzVmss`, and `Set-AzVmssStorageProfile`.
-* Updated `Set-AzVMDiagnosticsExtension` to correct capitalization by passing "StorageAccount" as configuration property instead of "storageAccount".
+* Addressed bug in `Remove-AzVmss` to throw error when `-InstanceId` is null. [#21162]
 
 ## Version 5.6.0
 * Added `-NetworkAccessPolicy` parameter to `New-AzSnapshotUpdateConfig`.

src/Compute/Compute/Generated/VirtualMachineScaleSet/VirtualMachineScaleSetDeleteInstancesMethod.cs

@@ -52,7 +52,7 @@ public override void ExecuteCmdlet()
                     IList<string> instanceIds = this.InstanceId;
 
                     Rest.Azure.AzureOperationResponse result = null;
-                    if (!string.IsNullOrEmpty(resourceGroupName) && !string.IsNullOrEmpty(vmScaleSetName) && instanceIds != null)
+                    if (!string.IsNullOrEmpty(resourceGroupName) && !string.IsNullOrEmpty(vmScaleSetName) && this.IsParameterBound(c => c.InstanceId))
                     {
                         result = VirtualMachineScaleSetsClient.DeleteInstancesWithHttpMessagesAsync(resourceGroupName, vmScaleSetName, instanceIds, forceDeletion:forcedelete).GetAwaiter().GetResult();
                     }