AZ Deployment Group What-If -- Azure Bicep Output Not Produced For Modules with Dependencies

[AErmie]

Describe the bug

When using az deployment group what-if with Azure Bicep templates that are called via modules, only modules without any dependencies actually produce/show their output (ie. what will be created). All other resources are not listed, giving the incorrect assumption that they will not be created.

Command Name
az deployment group what-if --resource-group GHES-aermie --template-file main.bicep

To Reproduce:

Steps to reproduce the behavior. Note that argument values have been redacted, as they may contain sensitive information.

Sample Bicep code

module nsgModule './nsg.bicep' = {
  name: 'nsgDeploy'
  params: {
    accountPrefix: accountPrefix
    location: location
    tags: tags
  }
}

module vnetModule './vnet.bicep' = {
  name: 'vnetDeploy'
  params: {
    accountPrefix: accountPrefix
    location: location
    tags: tags
    addressPrefix: addressPrefix
    ghes_subnetPrefix: ghes_subnetPrefix
    runners_subnetPrefix: runners_subnetPrefix
    ghes_nsgID: nsgModule.outputs.networkSecurityGroup_ID_GHES
    runners_nsgID: nsgModule.outputs.networkSecurityGroup_ID_Runners
  }
}

output networkSecurityGroup_ID_GHES string = nsgModule.outputs.networkSecurityGroup_ID_GHES
output networkSecurityGroup_Name_GHES string = nsgModule.outputs.networkSecurityGroup_Name_GHES
output networkSecurityGroup_Location_GHES string = nsgModule.outputs.networkSecurityGroup_Location_GHES
output networkSecurityGroup_SecurityRules_GHES string = nsgModule.outputs.networkSecurityGroup_SecurityRules_GHES
output networkSecurityGroup_ID_Runners string = nsgModule.outputs.networkSecurityGroup_ID_Runners
output networkSecurityGroup_Name_Runners string = nsgModule.outputs.networkSecurityGroup_Name_Runners
output networkSecurityGroup_Location_Runners string = nsgModule.outputs.networkSecurityGroup_Location_Runners
output networkSecurityGroup_SecurityRules_Runners string = nsgModule.outputs.networkSecurityGroup_SecurityRules_Runners

output virtualNetwork_Name string = vnetModule.outputs.virtualNetwork_Name
output virtualNetwork_Location string = vnetModule.outputs.virtualNetwork_Location
output virtualNetwork_AddressPrefix string = vnetModule.outputs.virtualNetwork_AddressPrefix
output virtualNetwork_SubnetAddressPrefix_GHES string = vnetModule.outputs.virtualNetwork_SubnetAddressPrefix_GHES
output virtualNetwork_SubnetAddressPrefix_Runners string = vnetModule.outputs.virtualNetwork_SubnetAddressPrefix_Runners

Expected Behavior

From the above-listed Bicep example, output for both the NSG and VNET is expected, but only output for the NSG is produced.

Environment Summary

Windows-10-10.0.19041-SP0
Python 3.8.9
Installer: MSI

azure-cli 2.27.1

Extensions:
aks-preview 0.5.25
portal 0.1.2

Additional Context

It may be related to Issue #19308

[AErmie]

Note: This issue was originally posted in the Azure-CLI repo: Azure/azure-cli#19309
@ishepherd

[alex-frankel]

This is a dup of Azure/arm-template-whatif#157. We are currently investigating with how best to solve the issue. cc @shenglol as FYI