[FELIX-6009] Metatype AD empty String default value

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: metatype-1.2.2
• Fix Version/s: metatype-1.2.4
• Component/s: Metatype Service
• Assignee: Carsten Ziegeler
• Reporter: Andreas Lemmer
• Created: 27/Dec/18 00:39
• Updated: 18/Jan/21 16:02
• Resolved: 15/Jan/21 16:53

Description

I have an AD with a default value which is an empty string, like

<AD id="server" type="String" default=""/>

According to the OSGi Spec, the method AttributeDefinition.defaultValue() in this case must return an array with one element (which should be the empty string), because the cardinality is 0 (implicit) and the default is defined.

However, the Felix Metatype Service implementation returns null for defaultValue().

In my use case, this breaks everything, because a null value indicates a configuration error (default not given, although mandatory) whereas an empty string is perfectly fine.