[GROOVY-10089] SC: GroovyCastException for map value as constructor for Collection

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.0-beta-1, 3.0.11
• Component/s: Static compilation
• Assignee: Eric Milles
• Reporter: Eric Milles
• Created: 14/May/21 15:02
• Updated: 24/Jul/23 22:50
• Resolved: 14/May/21 19:37

Description

Our tree-building code is a bit more than this, but I was able to trim back and still produce the run-time exception:

def test(... attributes) {
    List one = [
        [id:'x', options:[count:1]]
    ]
    List two = attributes.collect {
        def node = Collections.singletonMap('children', one)
        if (node) {
            node = node.get('children').find { child -> child['id'] == 'x' }
        }
        // inferred type of node must be something like Map<String,List<...>>

        [id: it['id'], name: node['name'], count: node['options']['count']]
        //                                        ^^^^^^^^^^^^^^^ GroovyCastException (map ctor for Collection)
    }
    two
}

test( [id:'x'] )

Changing the type of "one" from "List" to "def" stops the madness.