Annotation default values if dynamic expression is null

[HeikoTheissen]

Consider the following annotations:

"@Capabilities.ComputeSupported": {"$Path": "NavigationProperty/BooleanProperty"},
"@Capabilities.SelectSupport": {"ComputeSupported": {"$Path": "NavigationProperty/BooleanProperty"}}

What are the annotation values if the NavigationProperty is null?

SelectSupport/ComputeSupported is effectively not given, because null is not an allowed value. Hence its default value false applies.

ComputeSupported is effectively not given, because null is not an allowed value. But does that mean that the default value true applies? In other words and in XML parlance, is this equivalent to

• <Annotation Term="Capabilities.ComputedSupported" /> (in which case the DefaultValue="true" would apply) or to

• no <Annotation> at all? In which case no DefaultValue would apply, but the general remarks would:

  A service is assumed to support by default the following capabilities even though an
  annotation doesn’t exist

  (Here $compute is not mentioned, so the assumption would be "not supported".)

[ralfhandl]

One could argue that these annotations are invalid because the type of the ValuePath expression is "nullable Boolean" and does not match the type of the term or term property "non-nullable Boolean".

Unfortunately we don't go into that level of detail in sections 14.4.1.7 Value Path and 14.4.1.2 Path Evaluation.

[HeikoTheissen]

One could argue that these annotations are invalid

Yes, but what follows from that? Servers cannot avoid such values if they use dynamic expressions. And the default values should come to the rescue in such cases. We should consider spelling that out in more detail.