*Motivation* A BC issue was introduced by #2501. If a function is submitted by old CLI, which only containers topics to serde map. The new function worker will fail trigger request because it can't find input specs.
``` 17:28:32.105 [function-web-7-9] ERROR org.apache.pulsar.functions.worker.rest.api.FunctionsImpl - Function in trigger function has more than 1 input topics @ /public/default/ex ``` *Changes* The functions worker should handle BC. *Tests* No tests are added here. Since it requires a BC testing framework to be able to submit a function to a new functions worker by old CLI. Created #2569 for adding a BC testing framework to cover such BC issues. [ Full content available at: https://github.com/apache/incubator-pulsar/pull/2570 ] This message was relayed via gitbox.apache.org for [email protected]
