Azure function: Value cannot be null. Parameter name: source

Question

Lately, when I call my Azure function, I see this exception come up whenever I try to make a HTTP request to the AddGroup function.

• It used to work until I updated some NuGet packages (specifically, Newtonsoft JSON 11.0.2)
• It works fine when I run the function locally- it's something to do with Azure
• I've pushed new code and restarted the function many times
• Other questions here say it might be a connection string problem, but, again, it works on my local machine and I haven't touched the connection strings
• When I try to attach the cloud debugger, the exception shows up before it hits any break points in my code.

Any ideas?

Time 11:04:02 AM
Exception type Microsoft.Azure.WebJobs.Host.FunctionInvocationException
Exception message Exception while executing function: AddGroup <--- Value cannot be null. Parameter name: source
Host.Results
Microsoft.Azure.WebJobs.Host.FunctionInvocationException: Exception while executing function: AddGroup ---> System.ArgumentNullException: Value cannot be null.

Parameter name: source

   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.FunctionInvocationFilterInvoker.<InvokeAsync>d__9.MoveNext()

--- End of stack trace from previous location where exception was thrown ---

   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)

   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.<InvokeAsync>d__24.MoveNext()

--- End of stack trace from previous location where exception was thrown ---

   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)

   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.<ExecuteWithWatchersAsync>d__23.MoveNext()

--- End of stack trace from previous location where exception was thrown ---

   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)

   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.<ExecuteWithLoggingAsync>d__22.MoveNext()

--- End of stack trace from previous location where exception was thrown ---

   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)

   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)

   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.<ExecuteWithLoggingAsync>d__16.MoveNext()

   --- End of inner exception stack trace ---

   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.<ExecuteWithLoggingAsync>d__16.MoveNext()

--- End of stack trace from previous location where exception was thrown ---

   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)

   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.<TryExecuteAsync>d__13.MoveNext()

Solution

I figured it out- I had a NuGet package conflict. One of my projects was trying to reference version Newtonsoft Json 9.0.1 (which the Azure Functions SDK depends on) and also 11.0.2, which another project wanted. I wound up having the other project also use the 9.0.1 version of the package.

Comments

[user3431501]

I believe this is the open GH issue github.com/Azure/azure-functions-host/issues/3370