az webapp identity assign wipes out access restrictions

Related command az webapp identity assign -g resourceGroupName -n resourceName --identities [system]

Describe the bug Enabling system managed identity for an Azure App Service wipes out access restrictions. This started happening recently, was fine 1-2 weeks ago.

To Reproduce Add an access restriction to an azure app service. Enable system managed identity for the app service by running the az webapp identity assign command.

Expected behavior Access restrictions should remain.

[zoeperryman]

This is a rather big issue for us as our deployments are now randomly removing the access restrictions and opening up what should be private services to the public internet.

I first found the issue setting the managed identity like this issue describes, but then found that some of our later scripts added a tag to the web app and that was also wiping the access restrictions. Both of these commands below appear to wipe the access restrictions.

az resource tag --tags MyTag=MyValue -g my-rg -n my-web-app --resource-type "Microsoft.Web/sites"

az webapp update -g my-rg -n my-web-app --set tags.MyTag=MyValue

I noticed this about a week ago, it didn’t seem to matter what cli version I used (had an old one and updated to the latest, both have the same problem)

[madsd]

@alin-devnet @ishepherd this issue should have been mitigated. Sorry for the inconvenience.