Method Extend

cel/env.go:534–600

Extend the current environment with additional options to produce a new Env. Note, the extended Env value should not share memory with the original. It is possible, however, that a CustomTypeAdapter or CustomTypeProvider options could provide values which are mutable. To ensure separation of state

(opts ...EnvOption)

// TypeProvider are immutable, or that their underlying implementations are based on the
// ref.TypeRegistry which provides a Copy method which will be invoked by this method.
func (e *Env) Extend(opts ...EnvOption) (*Env, error) {
	if _, chkErr := e.getCheckerOrError(); chkErr != nil {
		return nil, chkErr
	}

	prsrOptsCopy := slices.Clone(e.prsrOpts)
	chkOptsCopy := slices.Clone(e.chkOpts)
	varsCopy := slices.Clone(e.variables)
	macsCopy := slices.Clone(e.macros)
	progOptsCopy := slices.Clone(e.progOpts)
	validatorsCopy := slices.Clone(e.validators)
	costOptsCopy := slices.Clone(e.costOptions)

	// Copy the adapter / provider if they appear to be mutable.
	adapter := e.adapter
	provider := e.provider
	adapterReg, isAdapterReg := e.adapter.(*types.Registry)
	providerReg, isProviderReg := e.provider.(*types.Registry)
	// In most cases the provider and adapter will be a ref.TypeRegistry;
	// however, in the rare cases where they are not, they are assumed to
	// be immutable. Since it is possible to set the TypeProvider separately
	// from the TypeAdapter, the possible configurations which could use a
	// TypeRegistry as the base implementation are captured below.
	if isAdapterReg && isProviderReg {
		reg := providerReg.Copy()
		provider = reg
		// If the adapter and provider are the same object, set the adapter
		// to the same ref.TypeRegistry as the provider.
		if adapterReg == providerReg {
			adapter = reg
		} else {
			// Otherwise, make a copy of the adapter.
			adapter = adapterReg.Copy()
		}
	} else if isProviderReg {
		provider = providerReg.Copy()
	} else if isAdapterReg {
		adapter = adapterReg.Copy()
	}

	ext := &Env{
		parent:          e,
		Container:       e.Container,
		variables:       varsCopy,
		functions:       e.functions,
		macros:          macsCopy,
		contextProto:    e.contextProto,
		progOpts:        progOptsCopy,
		adapter:         adapter,
		features:        e.features,
		limits:          e.limits,
		appliedFeatures: e.appliedFeatures,
		libraries:       e.libraries,
		validators:      validatorsCopy,
		provider:        provider,
		chkOpts:         chkOptsCopy,
		prsrOpts:        prsrOptsCopy,
		costOptions:     costOptsCopy,