About Validation Providers

[mirko-pagliai]

I noticed that in terms of validation, there's no shortcut to perform a sort of OR between different rules (e.g., the field can be either date or datetime). And I can easily imagine that implementing something like this makes very little sense (so much implementation for a rarely used function).

Of course, it's possible to do so by implementing your own callback, I know.

However, I saw that the Validation Providers section is correctly included, and that it correctly mentions the table provider and the default provider.

So, might it be useful to mention that the validator is available for some methods, such as getProvider(), which can then also allow statically access to the provider's methods?

/** @var class-string<\Cake\Validation\Validation> $defaultProvider */
$defaultProvider = $validator->getProvider('default');

$validator
    ->add('start_on', 'dateOrDatetime', [
        'rule' => function ($value) use ($defaultProvider): bool {
            return $defaultProvider::datetime($value) || $defaultProvider::date($value);
        },
        'message' => __('It should be a date or a date and time'),
    ])

I ask a question before opening a PR because maybe it's stupid or useless, or because there's a better way that I haven't found. If it's okay, I can do a PR myself (this way I avoid always delegating my ideas/suggestions, when I can! :-))

p.s. In the same section, immediately after, the possibility of using callbacks is mentioned. But I don't see a close correlation with providers (that's the section). Is it normal for it to be there?

[markstory]

I ask a question before opening a PR because maybe it's stupid or useless, or because there's a better way that I haven't found. If it's okay, I can do a PR myself (this way I avoid always delegating my ideas/suggestions, when I can! :-))

You're correct, using a custom rule is the best way to model OR rules right now. If you don't plan on having dynamic default providers, your example could by simplified and use Validation::datetime() directly.