[jira] [Created] (FLINK-40844) Planner inserting a ghost column when all rows are partition keys

["Vas Shabu (Jira)" <ji...@apache.org>]

Vas Shabu created FLINK-40844:
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             Summary: Planner inserting a ghost column when all rows are partition keys
                 Key: FLINK-40844
                 URL: https://issues.apache.org/jira/browse/FLINK-40844
             Project: Flink
          Issue Type: Bug
            Reporter: Vas Shabu


While adding EXPR$0 handling for PTFs, we found SystemTypeInference always falls back to a phantom EXPR$0 column whenever the function's own output is empty — even when PARTITION BY or rowtime columns already populate the row:

- deriveFunctionOutputFields returns EXPR$0 unconditionally for an empty function output, without checking whether pass-through/rowtime columns already contributed fields.
- This produces a wrong resolved schema (extra column) and a codegen arity mismatch whenever an empty-output PTF is combined with PARTITION BY.
- Fix: only fall back to EXPR$0 when the whole assembled output row (pass-through + function output + rowtime) is empty.



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