Strings#splitStringByCommaToSet vs Strings#splitStringByCommaToArray

[dnhatn]

These two helper methods are expected to have the same behaviour. However, Strings#splitStringByCommaToSet trims the leading and trailing whitespace of the substrings, while Strings#splitStringByCommaToArray reserves them. This subtle difference can lead to unexpected bugs (For example #27708).

[jasontedor]

I am not sure if they are expected to have the same behavior. The relevant change is #19520 which deliberately changed the behavior of Strings#splitStringByCommaToSet to trim whitespace. Then we have Strings#tokenizeToStringArray which behaves like Strings#splitStringByCommaToArray except it trims whitespace.

[jasontedor]

I opened #27715 to rename Strings#splitStringByCommaToSet so that people do not think the behavior is the same on the basis of the names alone. I also added Javadocs, and cleaned up the related code.

[dnhatn]

Thank you @jasontedor.