fix(ci): Allow CI to use unpinned version of docker build image (#8943)

Author: PerfectSlayer

.github/workflows/update-docker-build-image.yaml

@@ -52,7 +52,7 @@ jobs:
           echo "::notice::Using Docker build image tag: ${TAG}"
       - name: Update the Docker build image in GitLab CI config
         run: |
-          sed -i 's|JAVA_BUILD_IMAGE_VERSION:.*|JAVA_BUILD_IMAGE_VERSION:"${{ steps.define-tag.outputs.tag }}"|' .gitlab-ci.yml
+          sed -i 's|BUILDER_IMAGE_VERSION_PREFIX:.*|BUILDER_IMAGE_VERSION_PREFIX:"${{ steps.define-tag.outputs.tag }}-"|' .gitlab-ci.yml
       - name: Commit and push changes
         env:
           GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}

.gitlab-ci.yml

@@ -27,7 +27,7 @@ variables:
   GRADLE_VERSION: "8.5" # must match gradle-wrapper.properties
   MAVEN_REPOSITORY_PROXY: "http://artifactual.artifactual.all-clusters.local-dc.fabric.dog:8081/repository/maven-central/"
   GRADLE_PLUGIN_PROXY: "http://artifactual.artifactual.all-clusters.local-dc.fabric.dog:8081/repository/gradle-plugin-portal-proxy/"
-  JAVA_BUILD_IMAGE_VERSION: "v25.05"
+  BUILDER_IMAGE_VERSION_PREFIX: "v25.05-"
   REPO_NOTIFICATION_CHANNEL: "#apm-java-escalations"
   DEFAULT_TEST_JVMS: /^(8|11|17|21)$/
   PROFILE_TESTS:
@@ -97,7 +97,7 @@ default:
   - echo "NORMALIZED_NODE_TOTAL=${NORMALIZED_NODE_TOTAL}, NORMALIZED_NODE_INDEX=$NORMALIZED_NODE_INDEX"
 
 .gradle_build: &gradle_build
-  image: ghcr.io/datadog/dd-trace-java-docker-build:${JAVA_BUILD_IMAGE_VERSION}-base
+  image: ghcr.io/datadog/dd-trace-java-docker-build:${BUILDER_IMAGE_VERSION_PREFIX}base
   stage: build
   variables:
     MAVEN_OPTS: "-Xms64M -Xmx512M"
@@ -228,7 +228,7 @@ spotless:
 
 test_published_artifacts:
   extends: .gradle_build
-  image: ghcr.io/datadog/dd-trace-java-docker-build:${JAVA_BUILD_IMAGE_VERSION}-7 # Needs Java7 for some tests
+  image: ghcr.io/datadog/dd-trace-java-docker-build:${BUILDER_IMAGE_VERSION_PREFIX}7 # Needs Java7 for some tests
   stage: tests
   needs: [ build ]
   variables:
@@ -366,7 +366,7 @@ muzzle-dep-report:
 
 .test_job:
   extends: .gradle_build
-  image: ghcr.io/datadog/dd-trace-java-docker-build:$testJvm
+  image: ghcr.io/datadog/dd-trace-java-docker-build:${BUILDER_IMAGE_VERSION_PREFIX}$testJvm
   tags: [ "docker-in-docker:amd64" ] # use docker-in-docker runner for testcontainers
   needs: [ build_tests ]
   stage: tests