See this question on answers.nuxeo.com. Basically:
- Have an operation, whose id is "RandomStringGenerator"
- Have an automation chain, id "RandomStringGenerator" also
- The chain (1) "Fetcch Contect Document", then (2) RandomStringGenerator (the operation) and then (3) Update property
This failed (see the log in the quesiton). The log was not really useful actually - at least to me. So, we added a call to Notification > Log before calling the operation, and I could see hundreds of lines of my log, so I understood the problem: When the automation chain calls the operation, it calls the automation chain instead, because from Nuxeo standpoint, a chain and an operaiton are basically the same.
Note: I suspect there was seomthing in the log at startup, a warning or seomthing telling there sas 2 operaitons of the same id, buyt I don't have the logs anymore.
Anyway, fo fix the problem, we renamed the automation chain and all was good.
So, Nuxeo Studio should check the id of an automation chain is not already used by an operation (an operation loaded in Studio of course: All default operations + the ones from the registries), and should display its freaking red badge in case of problem (and should not accept the name at creation time too)