Chris@0: # Migration Guide
Chris@0: 
Chris@0: ## From v2 to v3
Chris@0: 
Chris@0: The changes made going from v2 to v3 were:
Chris@0: 
Chris@0: - Removal of the Hydrator subcomponent.
Chris@0: - Removal of the `CallbackHandler` class.
Chris@0: - Removal of `Zend\Stdlib\Guard\GuardUtils`.
Chris@0: 
Chris@0: ### Hydrators
Chris@0: 
Chris@0: The biggest single change from version 2 to version 3 is that the hydrator
Chris@0: subcomponent, which was deprecated in v2.7.0, is now removed. This means that if
Chris@0: you were using zend-stdlib principally for the hydrators, you need to convert
Chris@0: your code to use [zend-hydrator](https://github.com/zendframework/zend-hydrator).
Chris@0: 
Chris@0: This will also mean a multi-step migration. zend-stdlib v3 pre-dates
Chris@0: zend-hydrator v2.1, which will be the first version that supports zend-stdlib v3
Chris@0: and zend-servicemanager v3. If you are using Composer, the migration should be
Chris@0: seamless:
Chris@0: 
Chris@0: - Remove your zend-stdlib dependency:
Chris@0: 
Chris@0:   ```bash
Chris@0:   $ composer remove zendframework/zend-stdlib
Chris@0:   ```
Chris@0: 
Chris@0: - Update to use zend-hydrator:
Chris@0: 
Chris@0:   ```bash
Chris@0:   $ composer require zendframework/zend-hydrator
Chris@0:   ```
Chris@0: 
Chris@0: When zend-hydrator updates to newer versions of zend-stdlib and
Chris@0: zend-servicemanager, you will either automatically get those versions, or you
Chris@0: can tell composer to use those specific versions:
Chris@0: 
Chris@0: ```bash
Chris@0: $ composer require "zendframework/zend-stdlib:^3.0"
Chris@0: ```
Chris@0: 
Chris@0: ### CallbackHandler
Chris@0: 
Chris@0: `Zend\Stdlib\CallbackHandler` primarily existed for legacy purposes; it was
Chris@0: created before the `callable` typehint existed, so that we could typehint PHP
Chris@0: callables. It also provided some minimal features around lazy-loading callables
Chris@0: from instantiable classes, but these features were rarely used, and better
Chris@0: approaches already exist for handling such functinality in zend-servicemanager
Chris@0: and zend-expressive.
Chris@0: 
Chris@0: As such, the class was marked deprecated in v2.7.0, and removed for v3.0.0.
Chris@0: 
Chris@0: ### GuardUtils
Chris@0: 
Chris@0: Version 3 removes `Zend\Stdlib\Guard\GuardUtils`. This abstract class existed to
Chris@0: provide the functionality of the various traits also present in that
Chris@0: subcomponent, for consumers on versions of PHP earlier than 5.4. Since the
Chris@0: minimum required version is now PHP 5.5, the class is unnecessary. If you were
Chris@0: using it previously, compose the related traits instead.