Propagating @singular/ @plural

[daogrady]

Problem

For each entity in a model, cds-typer generates a singular and a plural entity.
As CDS assumes entities to be described in plural form, the entity's name in CSN is assumed to be the plural form, and a singular form is automatically derived.
As this mechanism is very prone to errors, users can specify a custom name for either singular or plural (or both) using the @singular and @plural annotations.

These annotations are meant only for the entity they are attached to. cds-typer will make sure these annotation stay at their respective root entity. If @singular and @plural were propagated, they could spread to unrelated entities through aspects and cause naming collisions:

@plural: 'Magic'
aspect MyAspect {}

entity X: MyAspect {}
entity Y: MyAspect {}
entity Z: MyAspect {}

would result in

class X {}
class MyAspect extends Array<X> {}

class Y {}
class MyAspect extends Array<Y> {}

class Z {}
class MyAspect extends Array<Z> {}

But in some cases, it may actually be desirable to retain these annotations. For example, when projecting on an entity without renaming it:

@singular: 'Scroll'
entity Book {}

service Bookshop {
  entity Book as projection on Book {}  // Bookshop.Book should actually become Bookshop.Scroll, for convenience
}

Solutions

Repeat @singular/ @plural

This is the current solution. If a users wants to have custom singular/ plural for projections, they have to repeat the annotation on the projection.

Another Annotation

Have another annotation that expresses that @singular/ @plural on this entity should be propagated:

@propagateSingular: true
@singular: 'Scroll'
entity Book {}

Meta Annotation

Introduce an annotation for the two inflection annotations:

@@propagate: true
@singular: 'Scroll'
entity Book {}

This would require involvement with the compiler, as this kind of meta annotations is not supported as of today.

Object-Valued @singular/ @plural

In addition to string values, allow object values containing this type of meta information:

@singular: { value: 'Scroll', propagate: true }
entity Book {}

Globally Configure cds-typer

Have a setting to force cds-typer to always or never propagate inflection annotations:

cds-typer --propagateInflection true "*"

Related Issues

The current behaviour of not propagating @singular/ @plural, whereas all other annotations are propagated, caused confusion at least once in the past
#425