this doesn't seem to fully work from what i can see:

the hydra:template looks correct and has foo[before],foo[strictly_before],foo[after],foo[strictly_after] etc...
but the swagger docs do not have 4 fields for before, strictly_before etc... do you know where this is done please @soyuka ?

ok, actually, if you try to use a different property name on your entity to your resource class, like the following, the hydra:template is then incorrect and will just have birthday with no [before] etc...

#[ORM\Entity]
class Agent
{
    #[ORM\Column]
    public ?\DateTimeImmutable $dob = null;

}
...

#[ApiFilter(DateFilter::class, properties: ['dob'], alias: 'app_filter_date')]
#[ApiResource(
    shortName: 'Agent',
    operations: [
        new GetCollection(parameters: [
            'birthday' => new QueryParameter(filter: 'app_filter_date'. property: 'dob'),
        ]),
    ],
    stateOptions: new Options(entityClass: Agent::class)
)]
class AgentApi
{
...
}

Querying this does work as expected however:
/api/agents?birthday[after]=2024-01-01

[before] is a value of our parameter though it should not appear in the template?

[before] is a value of our parameter though it should not appear in the template?

yes, it should appear in the template as per this test: