I have three concerns with the proposed solution:

1. The date format will behave differently if \IntlDateFormatter is available or not. I mean you have to know about the internal code to choose the right format.
2. There is no way to easily configure a date format for all constraints.
3. I would like to have a way to add more custom configurable formats (eg: for [Validator] Support \DateInterval in comparison constraints #33401) and we are not going to pile arguments everywhere.

I tried to resolve this issue at least 3 times but never came out with something good enough to me. I think the difficulty is that the formatting logic is internal to ConstraintValidator, it's nowhere in contracts. Having a real formatting system in the component could do the job. It could make sense at the violation builder level, but we cannot change the setParameter() method. Maybe we can add setParameterToFormat(string $key, mixed $value, int $flags) and then have a system that format the value to a string? It would be easy to hook in to add "custom" formatters. We would still need to find a way to easily allow override of the formats in the constraints.

Having a real formatting system in the component could do the job.

https://github.com/symfony/symfony/blob/5.x/src/Symfony/Component/Translation/Formatter/MessageFormatterInterface.php 😅

i'd be generally curious if we can move formatting to the translation level using ICU formats.

eg. to avoid duplicating the message, perhaps a special translation key solely for date values.

Having a real formatting system in the component could do the job.

https://github.com/symfony/symfony/blob/5.x/src/Symfony/Component/Translation/Formatter/MessageFormatterInterface.php 😅

i'd be generally curious if we can move formatting to the translation level using ICU formats.

eg. to avoid duplicating the message, perhaps a special translation key solely for date values.

That could be a solution the default value should be full date format as that is how it is now

The date format will behave differently if \IntlDateFormatter is available or not. I mean you have to know about the internal code to choose the right format.

I'm facing the issue where the tests do not provide the intl extension and tests break... I don't know what is the right way to fix it.

I'm very interesting about this feature. What is missing for the PR will be merged ?

Closing for the reasons explained by @fancyweb