/Drupal 8

function hook_module_implements_alter

hook_module_implements_alter(&$implementations, $hook)

Alter the registry of modules implementing a hook.

This hook is invoked during \Drupal::moduleHandler()->getImplementations(). A module may implement this hook in order to reorder the implementing modules, which are otherwise ordered by the module's system weight.

Note that hooks invoked using \Drupal::moduleHandler->alter() can have multiple variations(such as hook_form_alter() and hook_form_FORM_ID_alter()). \Drupal::moduleHandler->alter() will call all such variants defined by a single module in turn. For the purposes of hook_module_implements_alter(), these variants are treated as a single hook. Thus, to ensure that your implementation of hook_form_FORM_ID_alter() is called at the right time, you will have to change the order of hook_form_alter() implementation in hook_module_implements_alter().


$implementations: An array keyed by the module's name. The value of each item corresponds to a $group, which is usually FALSE, unless the implementation is in a file named $module.$group.inc.

$hook: The name of the module hook being implemented.

Related topics

Define functions that alter the behavior of Drupal core.


core/lib/Drupal/Core/Extension/module.api.php, line 119
Hooks related to module and update systems.


function hook_module_implements_alter(&$implementations, $hook) {
  if ($hook == 'form_alter') {
    // Move my_module_form_alter() to the end of the list.
    // \Drupal::moduleHandler()->getImplementations()
    // iterates through $implementations with a foreach loop which PHP iterates
    // in the order that the items were added, so to move an item to the end of
    // the array, we remove it and then add it.
    $group = $implementations['my_module'];
    $implementations['my_module'] = $group;

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