Function flattenStructFields

enterprise/audit/diff.go:186–229

flattenStructFields will return all top level fields for a given structure. Only anonymously embedded structs will be recursively flattened such that their fields are returned as top level fields. Named nested structs will be returned as a single field. Conflicting field names need to be handled by

(leftV, rightV reflect.Value)

// as a single field.
// Conflicting field names need to be handled by the caller.
func flattenStructFields(leftV, rightV reflect.Value) ([]fieldDiff, error) {
	// Dereference pointers if the field is a pointer field.
	if leftV.Kind() == reflect.Ptr {
		leftV = derefPointer(leftV)
		rightV = derefPointer(rightV)
	}

	if leftV.Kind() != reflect.Struct {
		return nil, xerrors.Errorf("%q is not a struct, kind=%s", leftV.String(), leftV.Kind())
	}

	var allFields []fieldDiff
	rightT := rightV.Type()

	// Loop through all top level fields of the struct.
	for i := 0; i < rightT.NumField(); i++ {
		if !rightT.Field(i).IsExported() {
			continue
		}

		var (
			leftF  = leftV.Field(i)
			rightF = rightV.Field(i)
		)

		if rightT.Field(i).Anonymous {
			// Anonymous fields are recursively flattened.
			anonFields, err := flattenStructFields(leftF, rightF)
			if err != nil {
				return nil, xerrors.Errorf("flatten anonymous field %q: %w", rightT.Field(i).Name, err)
			}
			allFields = append(allFields, anonFields...)
			continue
		}

		// Single fields append as is.
		allFields = append(allFields, fieldDiff{
			LeftF:     leftF,
			RightF:    rightF,
			FieldType: rightT.Field(i),
		})
	}
	return allFields, nil
}

// derefPointer deferences a reflect.Value that is a pointer to its underlying
// value. It dereferences recursively until it finds a non-pointer value. If the