Reinstate support for mariadb-r2dbc

[mshima]

spring-data-r2dbc used to depend on r2dbc bom:
https://github.com/spring-projects/spring-data-r2dbc/blob/e8ba67be6b35d147b5d10ec02bff81a12da75db2/pom.xml#L69-L75

which manages r2dbc-mariadb:
https://github.com/r2dbc/r2dbc-bom/blob/03ff2d7b854d2f162952c5705f2630faf4c501b4/pom.xml#L79-L83

As of version 3.0.0-RC1, r2dbc-mariadb is not managed:

spring-data-relational/spring-data-r2dbc/pom.xml

Lines 201 to 236 in 04aacd8

	<!-- R2DBC Drivers -->
	<dependency>
	<groupId>org.postgresql</groupId>
	<artifactId>r2dbc-postgresql</artifactId>
	<version>${r2dbc-postgresql.version}</version>
	<optional>true</optional>
	</dependency>
	<dependency>
	<groupId>io.r2dbc</groupId>
	<artifactId>r2dbc-h2</artifactId>
	<version>${r2dbc-h2.version}</version>
	<scope>test</scope>
	</dependency>
	<dependency>
	<groupId>io.r2dbc</groupId>
	<artifactId>r2dbc-mssql</artifactId>
	<version>${r2dbc-mssql.version}</version>
	<scope>test</scope>
	</dependency>
	<dependency>
	<groupId>com.oracle.database.r2dbc</groupId>
	<artifactId>oracle-r2dbc</artifactId>
	<version>${oracle-r2dbc.version}</version>
	<scope>test</scope>
	</dependency>
	<dependency>
	<groupId>io.r2dbc</groupId>
	<artifactId>r2dbc-spi-test</artifactId>
	<version>${r2dbc-spi.version}</version>
	<scope>test</scope>
	</dependency>

Is this a bug or a design decision?

[mp911de]

That's correct, as there is no 1.0-compliant version of the MariaDB driver.

[mraible]

@mp911de Do you know if there's an issue to track for the 1.0-compliant version? Also, what library are you referring to as 1.0?

[mp911de]

1.0 refers to the R2DBC specification version in this context, apologies for ambiguity. MariaDB is stuck on version 0.9 of the R2DBC spec. Upgrading to R2DBC 1.0 doesn't require much of a change, however, the changes are binary incompatible in comparison to 0.9.x.

[mshima]

Issue to track: https://jira.mariadb.org/projects/R2DBC/issues/R2DBC-60?filter=allopenissues

[mraible]

Thanks for the details y'all!

[mshima]

mariadb-r2dbc should be r2dbc 1.0 compliant now.
@mp911de is there any plan to add mariadb-r2dbc again?