mbutrovich opened a new pull request, #1697:
URL: https://github.com/apache/datafusion-comet/pull/1697

   ## Which issue does this PR close?
   
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   Closes #.
   
   ## Rationale for this change
   
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   Spark SQL's `decode` with two arguments converts a binary column to a string 
given an encoding from one of 'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 
'UTF-16LE', 'UTF-16'. 
   
   
https://github.com/apache/spark/blob/ef336ad51ba62e64a77896b9da12791051fa92cb/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala#L3028.
   
   Comet currently has no support for this expression, and this PR adds 'UTF-8' 
support.
   
   ## What changes are included in this PR?
   
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   There is no need to duplicate the description in the issue here but it is 
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   Convert a `StringDecode` expression to a `Cast` but only for the 'UTF-8' 
case. This scenario maps nicely to an Arrow cast with the safe option to 
replace invalid values with nulls:
   
   
https://github.com/apache/arrow-rs/blob/07093a49eface9be9208dd427b810abba8d0a755/arrow-cast/src/cast/string.rs#L342
   
   Other encodings are currently unsupported, however 'US-ASCII' might be easy 
to convert into the `ascii` scalar function. I need to confirm that the 
semantics match.
   
   ## How are these changes tested?
   
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   New fuzz test and existing Spark SQL tests.


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