LorenzoMartini commented on code in PR #36457: URL: https://github.com/apache/spark/pull/36457#discussion_r866773711
########## sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/regexpExpressions.scala: ########## @@ -642,7 +642,7 @@ case class RegExpReplace(subject: Expression, regexp: Expression, rep: Expressio } val source = s.toString() val position = i.asInstanceOf[Int] - 1 - if (position < source.length) { + if (position < source.length || (position == 0 && source.equals(""))) { Review Comment: IIC `position` is just i-1 and that is just the position the user asks the regex replace to start from no (https://github.com/apache/spark/blob/08c07a17717691f931d4d3206dd0385073f5bd08/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/regexpExpressions.scala#L598)? And `i` would be 1 by default if users don't specify a position (https://github.com/apache/spark/blob/08c07a17717691f931d4d3206dd0385073f5bd08/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/regexpExpressions.scala#L601-L602). So if user doesn't specify `pos`, then it would always be 1 and therefore `position` will always be 0. So ultimately the check `position==0` is not addressing the empty string case -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org