Missing static property setter doesn't fail at compile time

Question

I've encountered an odd bug where Apex code was assigning a value to a static property without a setter defined.

Below is a simplified version of the code:

@isTest
public class PropertySettingTest {

    public static boolean testBooleanProp {
        get {
            return false;
        }
    }

    static testMethod void setPropertyUnitTest() {
        System.assert(!testBooleanProp);

        testBooleanProp = true;

        System.assert(!testBooleanProp);
        System.debug(testBooleanProp);
    }
}

When assigning the property I'd expect to get an error when saving/compiling like:

Save error: Variable is not visible: testBooleanProp

However, is saves and runs. The property assignment has no affect.

I did another test, and if the property isn't static the code fails to save/compile as expected.

Am I missing something or is this a bug? I'd like some confirmation before raising a support case.

Answer 1

According to the Apex code reference on properties a property with only a get accessor is considered read-only. The reference has a section on static properties and it does not state that they behave any differently.

I performed a quick test and added a set and removed the get and I got the error when trying to read the variable. This inconsistency adds to the case that it is an issue.

public static boolean testBooleanProp {
    set;
}

static testMethod void setPropertyUnitTest() {
    // Causes variable is not visible error due to no get accessor defined.
    System.debug(testBooleanProp);
}

I'm with you that this looks like a defect.