Key fields not required

[HeikoTheissen]

Currently, non-computed key properties are required in OpenAPI. But this ignores the case of key properties that can be either provided or omitted (in which case they are computed by the server).

We have three types of key properties

Annotation of key property	Meaning for create request	contained in OpenAPI -create schema	required
Core.Computed	Must not be provided, computed by server	no	no
Core.ComputedDefaultValue	May be provided	yes	no
Neither	Must be provided, validated by server	yes	yes

This pull request corrects the OpenAPI description for the second type.

[ralfhandl]

A test case with this annotation would be nice. Could be an existing one with the annotation added, I think we have enough "non-computed" key properties in the examples 😎

[HeikoTheissen]

Common.FieldControl = Mandatory means that the field must have a value for the entity to have a valid state. But this value can be set after creation, or during creation by the server. In any case, such a field is not required in the -create schema.

[ralfhandl]

such a field is not required in the -create schema

This is correct, but someone might miss this only possibility to mark a field as "required" in the create structure.

The correct way to do that would be via Capabilities.InsertRestrictions/RequiredProperties, which is currently not evaluated by this transformation.

What I am trying to express: this correction may disappoint some users, and there is no mitigation.

[HeikoTheissen]

What I am trying to express: this correction may disappoint some users, and there is no mitigation.

That's for the future phase (#291):

odata-openapi/tools/V4-CSDL-to-OpenAPI.xsl

Lines 1451 to 1463 in 7a28882

	<!-- non-computed key properties are required, as are Capabilities.InsertRestrictions/RequiredProperties -->
	<xsl:for-each select="$structuredType/edm:Property[
	(@Name=../edm:Key/edm:PropertyRef/@Name and not(@id=//edm:Annotation[not(@Qualifier) and
	(@p2:Term='Org.OData.Core.V1.Computed' and not(@Bool='false') or
	@p2:Term='Org.OData.Core.V1.ComputedDefaultValue' and not(@Bool='false') or
	@p2:Term='Org.OData.Core.V1.Permissions' and @p2:EnumMember='Org.OData.Core.V1.Permission/Read' or
	@p2:Term='com.sap.vocabularies.Common.v1.FieldControl' and @p2:EnumMember='com.sap.vocabularies.Common.v1.FieldControlType/ReadOnly')]/@target)) or
	@Name=//edm:Annotation[not(@Qualifier) and id(@target)/@p1:EntityType=$structuredType/@id and @p2:Term='Org.OData.Capabilities.V1.InsertRestrictions']
	/edm:Record/edm:PropertyValue[@Property='RequiredProperties']/edm:Collection/edm:PropertyPath or
	@Name=//edm:Annotation[not(@Qualifier) and @p2:Term='Org.OData.Capabilities.V1.NavigationRestrictions']
	/edm:Record/edm:PropertyValue[@Property='RestrictedProperties']/edm:Collection
	/edm:Record[edm:PropertyValue[@Property='NavigationProperty' and id(@p1:NavigationPropertyPath)/@p1:Type=$structuredType/@id]]/edm:PropertyValue[@Property='InsertRestrictions']
	/edm:Record/edm:PropertyValue[@Property='RequiredProperties']/edm:Collection/edm:PropertyPath]">

[HeikoTheissen]

The correct way to do that would be via Capabilities.InsertRestrictions/RequiredProperties, which is currently not evaluated by this transformation.

If this was strictly evaluated, the outcome would depend on the resource path. But the required belongs to a *-create schema which exists only once per entity type, not per resource path.

[ralfhandl]

the required belongs to a *-create schema which exists only once per entity type, not per resource path

Generating structures per resource path was considered and discarded due to the significantly increased size of the generated OpenAPI files. Given that OpenAPI files now serve as input to LLMs whose context size is still limited, file size will continue to matter for some time.

[VigneshSubramania91]

please proceed with merge.