Declarative HTTP client - @Format annotation ignored for form body arguments

[oujesky]

Expected Behavior

@Client("/")
public interface SomeClient {
    @Post("/form/body")
    @Produces(MediaType.APPLICATION_FORM_URLENCODED)
    HttpResponse<String> sendFormattedFormParameter(@Format("yyyy/MM/dd") LocalDate bodyDate);
}

...

client.sendFormattedFormParameter(LocalDate.of(2023, 9, 8));

when executed, request URL-encoded form body contains bodyDate=2023%2F09%2F08 as specified with the @Format("yyyy/MM/dd") annotation

Actual Behaviour

when executed, request URL-encoded form body contains bodyDate=2023-09-08

• the @Format annotation seems to be ignored when client method arguments are passed into URL-encoded form body
• the @Format annotation correctly works for query parameters

Steps To Reproduce

please see example application

• execute FormFormatTest
• the test FormFormatTest#testFormParameter() will fail with Expected: 2023/09/08 Actual: 2023-09-08
• the client with @Format annotation is defined in FormFormatClient

Environment Information

• JDK 17
• MacOS

Example Application

https://github.com/oujesky/micronaut-client-format-bug

Version

4.1.0