Add Drush command to determine the next update hook and scaffold boilerplate

[Grashunk]

Is your feature request related to a problem? Please describe.
When working on Drupal updates, teams frequently need to add new hook_update_N() or hook_post_update_NAME() implementations. Determining the next valid update ID and creating the correct boilerplate is repetitive and error-prone. Developers often guess an ID, run drush updb, and see “No updates pending,” because that ID has already run or was removed from code. This slows iteration and causes confusion across environments.

Describe the solution you'd like
Introduce a Drush command that discovers the next valid update hook ID for a given module and can scaffold a ready-to-use boilerplate file/function.

Describe alternatives you've considered
Manually checking via:
drush php:eval 'print_r(\Drupal::keyValue("system.schema")->get("my_module"));'
Then hand-crafting files and function names. Works, but is slow, inconsistent, and not CI-friendly.

Project-local scripts. Not reusable, drift across teams.

[Grashunk]

I had sovled this locally like this:

<?php

namespace Drupal\YOUR_MODULE\Commands;

use Drush\Commands\DrushCommands;

/**
 * Provides a command to generate a new update hook for a module.
 */
class GenerateUpdateCommand extends DrushCommands {

  /**
   * Generate a new update hook boilerplate.
   *
   * @command generate:update
   * @param string $module
   *   The machine name of the module (e.g. my_module).
   *
   * @usage drush generate:update my_module
   *   Creates a new update hook skeleton in my_module.install.
   */
  public function generateUpdate(string $module): void {
    // Path to the module.
    $moduleHandler = \Drupal::service('module_handler');
    $modulePath = $moduleHandler->getModule($module)?->getPath();

    if (!$modulePath) {
      $this->io()->error("Module '$module' not found or not enabled.");
      return;
    }

    $installFile = DRUPAL_ROOT . '/' . $modulePath . '/' . $module . '.install';

    // Determine last executed update number.
    $schemaStore = \Drupal::keyValue('system.schema');
    $lastNumber = $schemaStore->get($module);

    if (!is_numeric($lastNumber)) {
      // No record yet – start at 9000 (Drupal best practice).
      $lastNumber = 9000;
    }

    $next = (int) $lastNumber + 1;

    // Boilerplate code.
    $code = <<<PHP

/**
 * Generated update hook for {$module} module.
 */
function {$module}_update_{$next}() {
  // Enter your code here.
}

PHP;

    // Ensure .install exists.
    if (!file_exists($installFile)) {
      file_put_contents($installFile, "<?php\n\n");
      $this->io()->writeln("Created new file: $installFile");
    }

    // Append the new hook.
    file_put_contents($installFile, $code, FILE_APPEND);
    $this->io()->success("Added {$module}_update_{$next}() to {$installFile}");
  }

}

But i have to admit to put it into the drush code is beyond my current skill level.