[GROOVY-11309] Optimise bytecode for empty list expressions

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.5.23
• Fix Version/s: 5.0.0-alpha-11
• Component/s: class generator, Compiler

Language

groovy

• Assignee: Eric Milles
• Reporter: Oscar N
• Created: 07/Feb/24 21:17
• Updated: 12/Nov/24 11:38
• Resolved: 06/Oct/24 17:30

Description

I have the following code:

class Book {
    String title
    String blurb = ''
    List<String> authors = []
}

When checking the compiled output, the creation of the empty list goes through ScriptBytecodeAdapter:

@Generated
public Book() {
    String var1 = "";
    this.blurb = var1;
    List var2 = ScriptBytecodeAdapter.createList(new Object[0]);
    this.authors = var2;
    MetaClass var3 = this.$getStaticMetaClass();
    this.metaClass = var3;
}

This case can be simplified to "List var2 = new ArrayList()", which would avoid some overhead and slightly improve @POJO support.

Issue Links

• is related to: GROOVY-10029 SC: produce direct method call for assignment of collection to array
• links to: GitHub Pull Request #2054