[jira] [Created] (GROOVY-10859) Regression in invoking method references to methods from List class when called on empty lists

[Marcin Erdmann (Jira)]

Marcin Erdmann created GROOVY-10859:
---------------------------------------

             Summary: Regression in invoking method references to methods from 
List class when called on empty lists
                 Key: GROOVY-10859
                 URL: https://issues.apache.org/jira/browse/GROOVY-10859
             Project: Groovy
          Issue Type: Bug
    Affects Versions: 4.0.0
            Reporter: Marcin Erdmann


While migrating from Groovy 3 to Groovy 4 I have uncovered a regression in how 
method references to methods on {{List}} are invoked when called on empty 
lists. The following test case passes on Groovy 3:
{code:java}
    def "method references from List class are invoked correctly on empty 
lists"() {
        given:
        def streamOfEmptyCollections = [[]].stream()

        when:
        def flattened = streamOfEmptyCollections.flatMap(List::stream).toList()

        then:
        flattened == []
    }
{code}
But on Groovy 4 it fails with the following error:
{noformat}
Condition not satisfied:

flattened == []
|         |
|         false
[interface java.util.List]
{noformat}
I believe that the regression was introduced by [this change to 
{{groovy.lang.MetaClassImpl.invokeMethodClosure()}}|https://github.com/apache/groovy/commit/22e5f3bb1823041f9b0445d8e1de0c02dfa87fd1#diff-c28986077bdc1a71b46273a2f3596d89d4608fadc5843b56ec0bc25894e19652R1084]
 which was part of the fix for GROOVY-10057.



--
This message was sent by Atlassian Jira
(v8.20.10#820010)