Nodes produce errors when nothing has changed

The nodes below are acting strangely.

When I run the graph for the first time they produce an error.
But if I type something between the “”, like “a”, run it (no errors btw), and then put it back to “” it runs with no errors.
If the code is left unchanged, why do they produce warnings in the first place?

I am confused…

Thank you

Dynamo only re-runs code on nodes that have changed data. This means that if you change an input in node 4 Dynamo doesn’t re-run nodes 1-3, it only updates node 4 and continues the computations downstream.

I don’t know where your error is coming from but this functionality might have something to do with why your values don’t update and the warning doesn’t return. Essentially your graph fails on the first run with no data, on the second run it succeeds, and then on the third run it doesn’t re-run computations and therefore doesn’t update.

I understand.
So, basically, I was getting the warning when using the GetItemAtIndex nodes below but replacing it by DS in a codeblock is not necessarily filtering the Empty Lists at the source.
The CodeBlocks still produce the full lists for each of the functions used in them.
Is that it?

And if so, there is no way, or workaround, to set this portion of my graph so that it does not create warnings in the absence of elements in the model.