[GROOVY-11285] Generated toList() and toMap() methods on records perform unnecessary wrapping

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 4.0.17
• Fix Version/s: 4.0.19, 5.0.0-alpha-6

Language

groovy

• Assignee: Paul King
• Reporter: Oscar N
• Created: 17/Jan/24 17:40
• Updated: 05/Mar/24 01:53
• Resolved: 19/Jan/24 21:47

Description

I have the following code:

import groovy.transform.CompileStatic

@CompileStatic
static void main(String[] args) {
    println(new Person("John", 42).size())
}

@CompileStatic
record Person(String name, int age) {} 

When checking the compiled output, the toList and toMap methods appear to call a helper method to create a mutable list and map, respectively. These are then wrapped inside another ArrayList/LinkedHashMap:

@Generated
public final List toList() {
    return new ArrayList(ScriptBytecodeAdapter.createList(new Object[]{this.name(), this.age()}));
}

@Generated
public final Map toMap() {
    return new LinkedHashMap(ScriptBytecodeAdapter.createMap(new Object[]{"name", this.name(), "age", this.age()}));
}

This wrapping is unnecessary.

Sidenote: Should these return mutable collections considering records are expected to be heavily immutable? If not, might be worth considering changing them to immutable in Groovy 5, something along the lines of:

@Generated
public final List toList() {
    return List.of(new Object[]{this.name(), this.age()});
}

@Generated
public final Map toMap() {
    return Map.of(new Object[]{"name", this.name(), "age", this.age()});
}