Python activity odd error

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1

Every now and again (running 100’s of flows). I am getting an odd error with the python activity:

strong textSystem.ArgumentNullException: String reference not set to an instance of a String.
strong textParameter name: s

I thought it might be an issue with what I am sending back so I just dropped a file from python and I am no longer sending anything back to uipath and I still randomly get this message on a flow or 2. I have checked the code and recreated the situation but 9 out of 10 times it works. Also, I am passing nothing back now so it can’t be that (and the python finishes as dropping the file in a shared drive is the last thing it does). I am starting to think this may be a bug. Though if anyone else has any ideas I am willing to try them.

2

@JustJim

Welcome to forums

As you are seeing in the error it’s a Argument Null Exception

It’s because if you are passing any null value to arguments then this type of exception will happen

So when you are getting this error, make a check on the arguments you are passing

Hope this may help you

thanks

3

Hi srini84 as noted its not null and nothing is being passed back (I use an activity now to just pull i the file. Also, please note it will run 9 out of 10 times fine and randomly fail 1 time (python completes 10 out of 10 times). The python is 100% successful (I have a file I can see with the values that should be in them). So I have no clue where this null value is coming from.

4

@JustJim

Can you share the entire error you are getting?

Thanks

5

System.InvalidOperationException: Python deserialization exception —> System.ArgumentNullException: String reference not set to an instance of a String.
Parameter name: s
at System.Text.Encoding.GetBytes(String s)
at UiPath.Shared.Service.PythonResponse.Deserialize(String json)
— End of inner exception stack trace —
at UiPath.Shared.Service.PythonResponse.Deserialize(String json)
at UiPath.Python.Service.PythonProxy.RequestAsync(PythonRequest request, CancellationToken ct)
at UiPath.Python.Service.PythonProxy.Shutdown()
at UiPath.Python.Impl.OutOfProcessEngine.Release()
at UiPath.Python.Activities.PythonScope.Cleanup()
at UiPath.Python.Activities.PythonScope.OnCompleted(NativeActivityContext context, ActivityInstance completedInstance)
at System.Activities.Runtime.ActivityCompletionCallbackWrapper.Invoke(NativeActivityContext context, ActivityInstance completedInstance)
at System.Activities.Runtime.CompletionCallbackWrapper.CompletionWorkItem.Execute(ActivityExecutor executor, BookmarkManager bookmarkManager)