Function collectViewUnionTypes

codegen/service/service_data.go:1147–1176

collectViewUnionTypes traverses the attribute to gather all union sum-type definitions referenced by view-projected types. It always uses the provided location for all nested user types so that unions are generated in the views package and refer to view-local types (preventing import cycles).

(att *expr.AttributeExpr, scope *codegen.NameScope, loc *codegen.Location, unions map[string]*UnionTypeData, seen map[string]struct{})

// location for all nested user types so that unions are generated in the views
// package and refer to view-local types (preventing import cycles).
func collectViewUnionTypes(att *expr.AttributeExpr, scope *codegen.NameScope, loc *codegen.Location, unions map[string]*UnionTypeData, seen map[string]struct{}) {
	if att == nil || att.Type == expr.Empty {
		return
	}
	switch dt := att.Type.(type) {
	case expr.UserType:
		if _, ok := seen[dt.ID()]; ok {
			return
		}
		seen[dt.ID()] = struct{}{}
		collectViewUnionTypes(dt.Attribute(), scope, loc, unions, seen)
	case *expr.Object:
		for _, nat := range sortedNamedAttributes(*dt) {
			collectViewUnionTypes(nat.Attribute, scope, loc, unions, seen)
		}
	case *expr.Array:
		collectViewUnionTypes(dt.ElemType, scope, loc, unions, seen)
	case *expr.Map:
		collectViewUnionTypes(dt.KeyType, scope, loc, unions, seen)
		collectViewUnionTypes(dt.ElemType, scope, loc, unions, seen)
	case *expr.Union:
		hash := dt.Hash()
		if _, ok := unions[hash]; !ok {
			unions[hash] = buildViewUnionTypeData(dt, scope, loc)
		}
		for _, nat := range dt.Values {
			collectViewUnionTypes(nat.Attribute, scope, loc, unions, seen)
		}
	}
}

// buildViewUnionTypeData creates the data needed to generate a sum-type union
// in the views package. Field types are computed using the view scope and are