Strange exception after migrating to Micronaut 4

[loicmathieu]

Hi,
After migrating to Micronaut 4 a lot of our HTTP endpoint fail with the following internal server error:

Failed to convert argument [q] for value [null] due to: Cannot construct instance of `io.micronaut.core.convert.value.ConvertibleValues` (no Creators, like default constructor, exist): abstract types either need to be mapped to concrete types, have custom deserializer, or contain additional type information\n at [Source: (io.netty.buffer.ByteBufInputStream); line: 1, column: 1

It occurs for all endpoints that have a parameter null, we do annotate nullable parameters with @Nullable.

We have a bunch of customization on top of the way the application is created and we use our own classloader, I don't know if it can cause the issue.

[graemerocher]

could you provide a reproducer in an issue report?

[loicmathieu]

Hi,
I think it'll be very hard to create a reproducer as it's a rather big project and we extend some of Micronaut API (we know we shouldn't do this but we had to). I am more asking for where to look at to try to understand what's going on.<
The current migration branch is here and this test shows the issue.

I noticed that the controller that generates the error has parameters without any HTTP annotations:

    @ExecuteOn(TaskExecutors.IO)
    @Post(uri = "executions/daily")
    @Operation(tags = {"Stats"}, summary = "Get daily statistics for executions")
    public List<DailyExecutionStatistics> dailyStatistics(
        @Parameter(description = "A string filter") @Nullable String q,
        @Parameter(description = "A namespace filter prefix") @Nullable String namespace,
        @Parameter(description = "A flow id filter") @Nullable String flowId,
        @Parameter(description = "The start datetime, default to now - 30 days") @Nullable @Format("yyyy-MM-dd'T'HH:mm[:ss][.SSS][XXX]") ZonedDateTime startDate,
        @Parameter(description = "The end datetime, default to now") @Nullable @Format("yyyy-MM-dd'T'HH:mm[:ss][.SSS][XXX]") ZonedDateTime endDate
    ) {
        // ...
    }
    ```
    
    It is called with every parameter inside the request body in JSON.

[graemerocher]

ok thanks could you report an issue with the details you have provided

[loicmathieu]

#10263

[loicmathieu]

I think we will move to use a POJO to bind the HTTP request instead of multiple parameters, this is more idiomatic (we do it for all other endpoints) and should fix the issue.

[loicmathieu]

I confirm that moving to a POJO for the request body instead of multiple parameters fixes the issue.

    @ExecuteOn(TaskExecutors.IO)
    @Post(uri = "executions/daily")
    @Operation(tags = {"Stats"}, summary = "Get daily statistics for executions")
    public List<DailyExecutionStatistics> dailyStatistics(@Body @Valid StatisticRequest statisticRequest) {
        // @TODO: seems to be converted back to utc by micronaut
        return executionRepository.dailyStatistics(
            statisticRequest.q(),
            tenantService.resolveTenant(),
            statisticRequest.namespace(),
            statisticRequest.flowId(),
            statisticRequest.startDate() != null ? statisticRequest.startDate().withZoneSameInstant(ZoneId.systemDefault()) : null,
            statisticRequest.endDate() != null ? statisticRequest.endDate().withZoneSameInstant(ZoneId.systemDefault()) : null,
            null,
            false
        );
    }

@Introspected
    public record StatisticRequest(
        @Parameter(description = "A string filter") @Nullable String q,
        @Parameter(description = "A namespace filter prefix") @Nullable String namespace,
        @Parameter(description = "A flow id filter") @Nullable String flowId,
        @Parameter(description = "A flow id filter") @Nullable @Format("yyyy-MM-dd'T'HH:mm[:ss][.SSS][XXX]") ZonedDateTime startDate,
        @Parameter(description = "The end datetime, default to now") @Nullable @Format("yyyy-MM-dd'T'HH:mm[:ss][.SSS][XXX]")ZonedDateTime endDate) {}