[jira] [Resolved] (GROOVY-10535) IF condition on empty Collection has different behavior than null Collection

["Eric Milles (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/GROOVY-10535?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Eric Milles resolved GROOVY-10535.
----------------------------------
    Fix Version/s: 5.0.0-alpha-1
       Resolution: Fixed

https://github.com/apache/groovy/commit/6b6a3e8a6fec2826f13cc0e6a52dcf1f25b4d74b

> IF condition on empty Collection has different behavior than null Collection
> ----------------------------------------------------------------------------
>
>                 Key: GROOVY-10535
>                 URL: https://issues.apache.org/jira/browse/GROOVY-10535
>             Project: Groovy
>          Issue Type: Bug
>    Affects Versions: 3.0.10
>         Environment: Groovy 3.0.10/OpenJDK 17.0.2 - Ubuntu 21.10
>            Reporter: Rodolfo Yanke
>            Assignee: Eric Milles
>            Priority: Major
>             Fix For: 5.0.0-alpha-1
>
>
> I believe this code should print "something" but doesn't work:
> {code:java}
> @CompileStatic
> class NotWorkingExample {
>   static void main(String[] args) {
>     Collection<String> values = null
>     for (i in 0..<200_000) {
>       printSomethingIfNotEmpty(values)
>     }
>     //never printed but it should
>     values = ['A']
>     printSomethingIfNotEmpty(values)
>   }
>   static printSomethingIfNotEmpty(Collection<String> values) {
>     if(values) {
>       println 'something'
>     }
>   }
> }
> {code}
> This one does print "something" because we pass an empty collection [] instead of null:
> {code:java}
> @CompileStatic
> class ItWorks {
>   static void main(String[] args) {
>       Collection<String> values = []
>       for (i in 0..<200_000) {
>         printSomethingIfNotEmpty(values)
>       }
>     //it works because [] was passed in the previous 200k calls
>     values = ['A']
>     printSomethingIfNotEmpty(values)
>   }
>   static printSomethingIfNotEmpty(Collection<String> values) {
>     if(values) {
>       println 'something'
>     }
>   }
> }{code}
> Some optimization is done differently when the condition is skipped too many times. Both classes should output "something" on the last method call.
> Thank you for the support.



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