Keep empty fields for fields validation, but not for documentation

internal/docs/exported_fields.go

@@ -27,6 +27,10 @@ func renderExportedFields(fieldsParentDir string) (string, error) {
 		// Keep External parameter when rendering fields, so we can render
 		// documentation for empty groups imported from ECS, for backwards compatibility.
 		KeepExternal: true,
+
+		// SkipEmptyFields parameter when rendering fields. In other cases we want to
+		// keep them to accept them for validation.
+		SkipEmptyFields: true,
 	}
 	validator, err := fields.CreateValidatorForDirectory(fieldsParentDir, fields.WithInjectFieldsOptions(injectOptions))
 	if err != nil {

internal/fields/dependency_manager.go

@@ -145,6 +145,9 @@ type InjectFieldsOptions struct {
 	// in previous versions on lazy resolution of external fields.
 	KeepExternal bool
 
+	// SkipEmptyFields can be set to true to skip empty groups when injecting fields.
+	SkipEmptyFields bool
+
 	root string
 }
 
@@ -210,7 +213,7 @@ func (dm *DependencyManager) injectFieldsWithOptions(defs []common.MapStr, optio
 			}
 		}
 
-		if skipField(def) {
+		if options.SkipEmptyFields && skipField(def) {
 			continue
 		}
 		updated = append(updated, def)