fordN commented on PR #23691:
URL: https://github.com/apache/datafusion/pull/23691#issuecomment-5622537264

   I also ran into the need for this fix independently when using a UDF in a 
subquery and the struct fields are accessed in the outer query. 
   
   ```sql
   SELECT decoded['from'], decoded['to'], MAX(decoded['value'])
   FROM (SELECT expensive_decode(a, b, c) AS decoded FROM t)
   GROUP BY 1, 2;
   ```
   
   I've tested it rebased onto current `main` branch (with 
https://github.com/apache/datafusion/pull/24720 and 
https://github.com/apache/datafusion/pull/23459).  All three of the guards 
appear to be needed and compose well. More specifically:
   - the aggregate shape I shared above, the issue's inline shape, and two 
no-GROUP-BY variants all evaluate
     the UDF once, in the logical plan and in `DataSourceExec`
   - `cargo test -p datafusion-optimizer extract_leaf` (55 tests) and 
`common_subexpr` (33) pass
   
   @tohuya6 if you are short on time I am happy to rebase and follow up to get 
this PR merged in, or open another PR that carries your commits with 
attribution.


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