CosmosDB 4.0.0-preview1 always throws an exception when AAD authentication is configured

Whenever I set up and run CosmosDBTrigger or CosmosDB to use AAD authentication, it throws a NullReferenceException and fails to start.

I checked and found that AzureComponentFactory is always passed null for DefaultCosmosDBServiceFactory. The root cause seems to be that AddAzureClientsCore is not registered in the DI.

Example (Service Bus Extension) : https://github.com/Azure/azure-sdk-for-net/blob/4162f6fa2445b2127468b9cfd080f01c9da88eba/sdk/servicebus/Microsoft.Azure.WebJobs.Extensions.ServiceBus/src/Config/ServiceBusHostBuilderExtensions.cs#L91-L93

Repro steps

1. Create new function (v3) project
2. Add CosmosDBTrigger function
3. Update Microsoft.Azure.WebJobs.Extensions.CosmosDB version 4.0.0-preview1
4. Setup RBAC and connection string
5. Run function app

Expected behavior

An error always occurs when starting Function.

[2021-09-01T15:07:18.499Z] Microsoft.Azure.WebJobs.Host: Error indexing method 'Function2'. 
Microsoft.Azure.WebJobs.Extensions.CosmosDB: Cannot create container information for TodoItem in database SampleDB with lease leases in database SampleDB : Object reference not set to an instance of an object. 
Microsoft.Azure.WebJobs.Extensions.CosmosDB: Object reference not set to an instance of an object.
[2021-09-01T15:07:18.536Z] Error indexing method 'Function2'

Actual behavior

CosmosDBTrigger and Managed Identity can be used without any errors.

Known workarounds

• Install Microsoft.Azure.WebJobs.Extensions.Storage (At the same time, AddAzureClientsCore is added to the DI, so)

Related information

• Microsoft.Azure.WebJobs.Extensions.CosmosDB : 4.0.0-preview1
• https://github.com/Azure/azure-webjobs-sdk-extensions/blob/dev/src/WebJobs.Extensions.CosmosDB/Config/CosmosDBWebJobsBuilderExtensions.cs#L21-L38

[ealsur]

Should be fixed in preview2 release

[ealsur]

@shibayan sent a PR with the fix, thanks for reporting