How to read from and write to the same file in Palantir Foundry?

Question

I have a very simple task of updating contents of a control file in Palantir Foundry. I need to read the contents of the file, perform a check and then write back to the same file. However, if I provide the same file as Input and Output in the transform, I get the following error -

Cyclic dependency exists in the code for the following Foundry datasets:...

Is there a workaround for this?

Answer 1

No there isn't a work around for this, this is by design to have reproducible builds. If you need to have a cycle in your build, you need to pass it through something outside of transforms, for example by using an ontology object with a write back to a different dataset which you can read from afterwards, so that it breaks the cyclic dependency.