[GROOVY-8770] CompileStatic ignores missing return statement

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Information Provided
• Affects Version/s: 2.4.15
• Component/s: Static compilation
• Labels: usability
• Assignee: Unassigned
• Reporter: Daniel Hammer
• Created: 29/Aug/18 08:24
• Updated: 03/Nov/23 19:23
• Resolved: 03/Nov/23 19:23

Description

The following simplified example compiles and executes, foo() returning false and bar() returning null.

@CompileStatic
class Pojo {

    boolean foo() {
    }
    
    Object bar() {
    }
}

 

With @CompileStatic enabled I would've expected sensible feedback from the compiler, example:

error: missing return statement

 

This symptom was discovered in a much larger method, where one branch was missing a return statement.
I'm suggesting adding some sensible feedback in this type of scenario, in-order to support developers relying on @CompileStatic for sanity checking. This would adhere to the principle of least astonishment, as locating this type of logical error can be time-consuming.