buildx push ignores <repository> tag in build

[tadgh]

I believe the <registry> tag is ignored when using <buildx>. Below are 2 separate configurations, the former attempts to uplaod to dockerhub, the latter successfully pushes to my private registry.

This setup attempts to push to dockerhub.

	<configuration>
			<registry>my-registry.com</registry>
			<images>
				<image>
					<name>my-image</name>
					<alias>my-image</alias>
					<build>
						<buildx>
							<platforms>
								<platform>linux/arm64</platform>
								<platform>linux/amd64</platform>
							</platforms>
						</buildx>
						<contextDir>${project.basedir}/target/dockercontext</contextDir>
						<tags>
							<tag>${project.version}</>
						</tags>
						<args>
							<TARFILE>dockerimage.tar.gz</TARFILE>
						</args>
					</build>
				</image>
			</images>
			<verbose>true</verbose>
		</configuration>

Using the push phase, this is the command that is generated:

docker
--config /path/to/docker buildx build
--progress=plain
--builder maven --platform linux/arm64,linux/amd64
--tag my-image:2022.11.PRE 
--push --file=/path/to/Dockerfile /path/to/tmp/docker-build

However if i instead prefix the image name with the registry, buildx respects it:

	<configuration>
			<registry>i-am-ignored.com</registry>
			<images>
				<image>
					<name>my-regsitry.com/my-image</name>
					<alias>my-image</alias>
					<build>
						<buildx>
							<platforms>
								<platform>linux/arm64</platform>
								<platform>linux/amd64</platform>
							</platforms>
						</buildx>
						<contextDir>${project.basedir}/target/dockercontext</contextDir>
						<tags>
							<tag>${project.version}</tag>
						</tags>
						<args>
							<TARFILE>dockerimage.tar.gz</TARFILE>
						</args>
					</build>
				</image>
			</images>
			<verbose>true</verbose>
		</configuration>

This setup generates the following buildx command, which does what i want it to do (e.g. push to my own registry).

docker --config /path/to/docker buildx build
--progress=plain
--builder maven 
--platform linux/arm64,linux/amd64  
--tag my-registry.com/my-image:2022.11
--push --file=/path/to/Dockerfile /path/to/tmp/docker-build

This tag allows buildx to upload to my own repository. I suppose all I can expect here is for the to be sneakily prefixed onto the tag during a buildx build, if present.

I've got it working, but just figure this would be a nice bit of syntactic sugar for people converting from non buildx builds to buildx builds.

Cheers

[tadgh]

Cheers, thanks :)