Clarify when defaultValue is used on ConfigProperty

Clarify when defaultValue is used @ConfigProperty(name="my.property", defaultValue="123") int myProp; In the javadoc of ConfigProperty, it has the following: The default value if the configured property value does not exist.

What if in a config source, the following config property is defined. my.property=abc.

Normally you will get IllegalArgumentException if the converter throws that. However, what if a converter did not throw an exception, it returns null. Will defaultValue or null be assigned to the variable?

• Option 1: defaultValue is not used and null -> myProp. Add a tck to verify this. Pros: honour the converter. In this way, converter has an option to assign null.

• Option 2: defaultValue is used. Javadoc needs to be updated to say: if converter return null, this value will be used. Pros: non null is returned. Cons: behaviour change. Not possible to return a null. Could be confusing if a property is defined with a value and the defaultValue is still used.

Thoughts?

[Emily-Jiang]

@Joseph-Cass Please open a new issue if further discussion is needed as this issue was closed and released. Any further discussions might confuse people.

[Emily-Jiang]

I also prefer option 1 for the same reason @radcortez mentioned besides there is no behaviour change. I’ll create a TCK to try the option 1 first to see whether we hit any issues.