Hibernate Reactive can't be used when agroal extension is present

[tomas1885]

Describe the bug

When Agroal extension is added as a depedency along side a reactive sql client, hibernate reactive can't be used.
As described in other issues, this prevents using reactive datasource along side flyway, liquibase, quartz etc. as they require a blocking datasource.
Once the agroal extension is present it automatically adds a jdbcdatasource that gets detected by the hibernate orm extension which is preset as a transient dependency for hibernate reactive.
This seems to actually boil down to the defineTypeOfImpliedPU method in the HiberanateOrmProcessor.
Other issues mentions that this can be fixed when Quarkus migrates to hibernate 6 and hibernate reactive 2.0, but it really seems like a "naive" assumption in the hibernate orm quarkus extension, which can be (hopefully) easy to fix by either allowing the user to disable blocking hibernate persistence unit, or by detecting the persistent unit associated datasource flavor (reactive or blocking).

#10716 (comment)
#13425

Expected behavior

When using Hibernate reactive with a reactive datasource configured, adding the agroal extension and configuring a blocking datasource, without associating it to hibernate persistence unit won't affect hibernate blocking/reactive mode.

Actual behavior

Configuring Hibernate Reactive with a reactive datasource as the datasource, while also adding another blocking datasource using agroal, causes all sort of exceptions due to the generation of ImpliedBlockingPersistenceUnitTypeBuildItem.

How to Reproduce?

No response

Output of uname -a or ver

No response

Output of java -version

17

GraalVM version (if different from Java)

No response

Quarkus version or git rev

3.0.3.Final

Build tool (ie. output of mvnw --version or gradlew --version)

Gradle 8.0.2

Additional information

No response

[quarkus-bot]

/cc @DavideD (hibernate-reactive), @Sanne (agroal,hibernate-reactive), @barreiro (agroal), @gavinking (hibernate-reactive), @yrodiere (agroal)

[tomas1885]

How changing the implementation of defineTypeOfImpliedPU to something like that:

   @BuildStep
    public ImpliedBlockingPersistenceUnitTypeBuildItem defineTypeOfImpliedPU(
            HibernateOrmConfig config,
            List<JdbcDataSourceBuildItem> jdbcDataSourcesBuildItem, //This is from Agroal SPI: safe to use even for Hibernate Reactive
            List<PersistenceXmlDescriptorBuildItem> actualXmlDescriptors,
            Capabilities capabilities) {
        var jdbcDataSourceEnabled = true;
        if (config.persistenceUnits.isEmpty()) {
            var defaultDataSourceJdbcPropertyKey = config.defaultPersistenceUnit.datasource
                    .map(name -> DataSourceUtil.dataSourcePropertyKeys(name, "jdbc"))
                    .orElse(List.of("quarkus.datasource.jdbc"));
            jdbcDataSourceEnabled = defaultDataSourceJdbcPropertyKey.stream()
                    .map(it -> ConfigUtils.getFirstOptionalValue(List.of(it), Boolean.class).orElse(true))
                    .reduce(
                            (enabled, otherEnabled) -> enabled && otherEnabled)
                    .orElse(true);
        } else {
            jdbcDataSourceEnabled = config.persistenceUnits.values()
                    .stream()
                    .map(it -> it.datasource.orElse(null))
                    .filter(Objects::nonNull)
                    .map(dataSource -> {
                        var datasourceJdbcEnabledKeys = DataSourceUtil.dataSourcePropertyKeys(dataSource, "jdbc");
                        //We have to iterate over each key separately since quarkus.datasource."name".jdbc and quarkus.datasource.name.jdbc would not return the same result
                        return datasourceJdbcEnabledKeys.stream()
                                .map(it -> ConfigUtils.getFirstOptionalValue(List.of(it), Boolean.class).orElse(true))
                                .reduce(
                                        (enabled, otherEnabled) -> enabled && otherEnabled)
                                .orElse(true);
                    }).reduce((dataSourceJdbcEnabled, anotherDataSourceJdbcEnabled) -> dataSourceJdbcEnabled
                            && anotherDataSourceJdbcEnabled)
                    .orElse(true);
        }
        //We won't generate an implied PU if there are explicitly configured PUs
        if (actualXmlDescriptors.isEmpty() == false) {
            //when we have any explicitly provided Persistence Unit, disable the automatically generated ones.
            return ImpliedBlockingPersistenceUnitTypeBuildItem.none();
        }

        // If we have some blocking datasources defined, we can have an implied PU
        if (((jdbcDataSourcesBuildItem.size() == 0) || !jdbcDataSourceEnabled)
                && capabilities.isPresent(Capability.HIBERNATE_REACTIVE)) {
            // if we don't have any blocking datasources and Hibernate Reactive is present,
            // we don't want a blocking persistence unit
            return ImpliedBlockingPersistenceUnitTypeBuildItem.none();
        } else {
            // even if we don't have any JDBC datasource, we trigger the implied blocking persistence unit
            // to properly trigger error conditions and error messages to guide the user
            return ImpliedBlockingPersistenceUnitTypeBuildItem.generateImpliedPersistenceUnit();
        }
    }

This fix passes all unit & integration tests (and a new integration test for this specific case), and actually fixes the issue. If no jdbc datasource is used for hibernate it assumed a non blocking persistent unit. I admit the implementation could be better, but hey, it works.
I can open a PR for that if I'll just get any response from you guys.

[yrodiere]

Please send a PR if it's not too much work, it'll be easier to determine what's going on with an actual diff.

[tomas1885]

@yrodiere I opened an initial PR so you can "catch the drift" of the problem and suggested solution