Regression in 0.48.1: Execution-level `pushRegistry` not applied to all images in multi-image builds

[vliska]

Title: Regression in 0.48.1: Execution-level pushRegistry not applied to all images in multi-image builds

Description:

Issue Description

After upgrading from docker-maven-plugin version 0.44.0 to 0.48.1, the execution-level <pushRegistry> configuration is no longer consistently applied to all images when building multiple images in a single project. The second image defaults to ghcr.io instead of using the configured registry.

Environment

• Plugin Version (broken): 0.48.1
• Plugin Version (working): 0.44.0
• Maven Version: 3.x
• Docker Version: 29+

Configuration

<plugin>
  <groupId>io.fabric8</groupId>
  <artifactId>docker-maven-plugin</artifactId>
  <version>0.48.1</version>
  <executions>
    <execution>
      <id>push-docker-image</id>
      <goals>
        <goal>push</goal>
      </goals>
      <phase>deploy</phase>
      <configuration>
        <pushRegistry>${docker.push.registry}</pushRegistry>
      </configuration>
    </execution>
  </executions>
  <configuration>
    <pullRegistry>${docker.registry}</pullRegistry>
    <pushRegistry>${docker.push.registry}</pushRegistry>
  </configuration>
</plugin>

<!-- In the actual plugin usage -->
<plugin>
  <groupId>io.fabric8</groupId>
  <artifactId>docker-maven-plugin</artifactId>
  <configuration>
    <images>
      <image>
        <name>mycompany/myapp-service:${project.version}</name>
        <alias>myapp-service</alias>
        <build>
          <dockerFile>Dockerfile-service</dockerFile>
        </build>
      </image>
      <image>
        <name>mycompany/myapp-client:${project.version}</name>
        <alias>myapp-client</alias>
        <build>
          <dockerFile>Dockerfile-client</dockerFile>
        </build>
      </image>
    </images>
  </configuration>
</plugin>

Where ${docker.push.registry} = registry.example.com:8080

Expected Behavior (0.44.0)

Both images should be pushed to the registry specified in the execution-level <pushRegistry> configuration:

• myapp-service → registry.example.com:8080 ✓
• myapp-client → registry.example.com:8080 ✓

Actual Behavior (0.48.1)

The first image pushes correctly, but the second image attempts to push to ghcr.io:

• myapp-service → registry.example.com:8080 ✓
• myapp-client → ghcr.io ✗

Build Output

[INFO] --- docker-maven-plugin:0.48.1:push (push-docker-image) @ myapp ---
[INFO] DOCKER> The push refers to repository [registry.example.com:8080/mycompany/myapp-service]
[INFO] DOCKER> 1.0.0-SNAPSHOT: digest: sha256:d331db402730c71f906aae31db1adf8fec0dec6c67be029afb33d28a3c6a0083 size: 6842
[INFO] DOCKER> Pushed mycompany/myapp-service:1.0.0-SNAPSHOT in 40 seconds 
[INFO] DOCKER> The push refers to repository [ghcr.io/mycompany/myapp-client]
[ERROR] DOCKER> Unable to push 'mycompany/myapp-client:1.0.0-SNAPSHOT' to registry 'ghcr.io' : unauthorized: unauthenticated: User cannot be authenticated with the token provided.

Request

Could you please:

1. Confirm if this is an intentional breaking change or a bug
2. Document the expected behavior for registry configuration precedence (execution-level vs image-level vs global)
3. If this is a bug, restore the 0.44.0 behavior where execution-level <pushRegistry> applies to all images

Thank you!