spring-boot-maven-plugin tags option, multiple issues

[DemianTinkiel]

when creating an image with spring-boot-maven-plugin I encountered the following issues:

1. Does not accept uppercase for tags, this doesn't allow me to add ${project.version}. Yet this is the default behaviour if tags is not specified. However, specifying tags overrides the behaviour, does not add to it (which is what I interpreted by the documentation by "One or more additional tags to apply to the generated image".)

Execution artifacts-prepare of goal org.springframework.boot:spring-boot-maven-plugin:2.7.3:build-image failed: Unable to parse image reference "3.0.0-SNAPSHOT". Image reference must be in the form '[domainHost:port/][path/]name[:tag][@digest]', with 'path' and 'name' containing only [a-z0-9][.][_][-] -> [Help 1]

2. Setting as latest generates 2 images - myRepo:8090/group/myproject:latest and latest:latest, both with the same hash

docker images | grep 757bb1ccd2ff
latest                              latest              757bb1ccd2ff   42 years ago    264MB
myRepo:8090/group/myproject         latest              757bb1ccd2ff   42 years ago    264MB

for issue 1, my pom is

<plugin>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-maven-plugin</artifactId>
  <version>2.7.3</version>
  <configuration>
    <docker>
      <publishRegistry>
        <url>${image.repo.url}</url>
        <username>${image.repo.user}</username>
        <password>${image.repo.pass}</password>
      </publishRegistry>
    </docker>
    <image>
      <name>${image.prefix}/${project.artifactId}</name>
      <tags>latest,${project.version}</tags>
    </image>
  </configuration>
  <executions>
    <execution>
      <id>artifacts-prepare</id>
      <goals>
        <goal>build-image</goal>
      </goals>
    </execution>
  </executions>
</plugin>

for issue 2 the pom is the same but with <tags>latest</tags>

[scottfrederick]

The values provided to the tags option should be full image references in the form of [image name]:[tag] or [repository]/[image name]:[tag]. It was done this way to provide users control over the full image reference. The name tags was chosen to be consistent with the pack CLI, but it can be confusing.

We should clarify this in the Maven and Gradle plugin documentation.

[scottfrederick]

Closing in favor of #33609.