[ ← blog / drupal ](/) Apr 02, 2024  ·  \#drupal  ·  3 min read 

# Ensuring smart\_date works for all versions of Drupal 10 and 11



At MidCamp a few weeks ago, [Martin Anderson-Clutz](https://www.drupal.org/u/mandclu) tapped me on the shoulder to check out a [Smart Date issue for compatibility with Drupal 10.2](https://www.drupal.org/project/smart_date/issues/3409287). As of Drupal 10.2, `ListItemBase::extractAllowedValues` takes an array as its first argument versus a string. The method used to explode a newline separated string into an array for its callers. I took a look at the issue. The change affected the `parseValues` method in the `SmartDateListItemBase` class. The `parseValues` method takes the field's values and passes them to `extractAllowedValues`, the method with a changed signature in Drupal 11.

The original method contained the following:

```php
  /**
   * {@inheritdoc}
   */
  public static function parseValues($values) {
    // Use the ListItemBase parsing function, but don't allow generated keys.
    $result = static::extractAllowedValues($values, 1);
    return $result;
  }
```

The fix was the following:

```php
  /**
   * {@inheritdoc}
   */
  public static function parseValues($values) {
    // Use the ListItemBase parsing function, but don't allow generated keys.
    $list = explode("\n", $values);
    $list = array_map('trim', $list);
    $list = array_filter($list, 'strlen');
    $result = static::extractAllowedValues($list, 1);
    return $result;
  }
```

Everyone RTBC'd a patch that would break the module, and any further fixes for folks below 10.2 would force a new minor version of the module! That's not good. Luckily, Drupal now has utilities that [make it easier than ever to write backward-compatible code](/blog/writing-backward-compatible-deprecation-fixes-contributed-modules-will-be-much-easier-drupal "Writing backward-compatible deprecation fixes for contributed modules will be much easier for Drupal 11").

I will walk through how I made the method work across multiple minor versions of Drupal core without triggering deprecation notices.

## Keep Smart Date compatible with all versions of Drupal 10

The `Drupal\Component\Utility\DeprecationHelper::backwardsCompatibleCall` method allows handling backward-compatible code branches. This utility was added to Drupal 10.1.3, and Smart Date supports those few sites that are still on Drupal. While they should upgrade to Drupal 10, we don't have to drop support for 10.0.

First, we check if the `DeprecationHelper` exists. If it doesn't, we know the code base is unaffected by the deprecation.

```php
    if (!class_exists(DeprecationHelper::class)) {
      return static::extractAllowedValues($values, 1);
    }
```

Then, we use `DeprecationHelper::backwardsCompatibleCall` to support calling two different code branches, the deprecated and current version, using closures. The first arguments to `backwardsCompatibleCall` allow determining whether the current version of Drupal is before or after the deprecation. The first callable is used if we're running a version after the deprecation; otherwise, the second one is.

```php
    return DeprecationHelper::backwardsCompatibleCall(
      \Drupal::VERSION,
      '10.2',
      static function () use ($values) {
        $list = explode("\n", $values);
        $list = array_map('trim', $list);
        $list = array_filter($list, 'strlen');
        return static::extractAllowedValues($list, 1);
      },
      static fn () => self::extractAllowedValues($values, 1)
    );

```

I took the proposed fix, which was correct, and placed it into the `currentCallable` argument and the existing code for the `deprecatedCallable` argument. Now, the maintainers of Smart Date can continue delivering bug fixes without leaving users behind, and users have a simple upgrade path without worrying about dropped minor version support of Drupal core.

You can find the full commit here: [smart\_date/-/commit/1dcd8f2beae45ceaa3e941c1819d6d1c0995dffb](https://git.drupalcode.org/project/smart_date/-/commit/1dcd8f2beae45ceaa3e941c1819d6d1c0995dffb)

 

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I write about Drupal, PHP, and the quiet infrastructure behind large sites — caching, config, and testing. New posts land every week or two.

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