test: enable compact object headers across test JVMs

[FrankChen021]

Description

Run Druid tests with -XX:+UseCompactObjectHeaders to detect regressions under JDK 25 compact object headers before changing runtime defaults.

• Enable the flag in the parent Surefire configuration, inherited by unit and embedded tests, and in the parallel-test profile that overrides test JVM arguments.
• Enable it in the embedded Docker-test Failsafe JVM.
• Set JAVA_TOOL_OPTIONS in the CI test image so containerized Druid services and task JVMs, including Kubernetes peon pods, inherit the flag. The Build the Docker image step appends the test-only ENV instruction to the Dockerfile streamed into a single Docker build, before the image is saved and loaded for testing.

Production launch scripts and distribution image defaults are unchanged. Historical Druid images used for backward-compatibility tests retain their existing JVM settings; they may use JDKs that do not support compact headers.

Validation

• Passed six CircularListTest unit cases and two SystemTableQueryTest embedded cases with JDK 25:

  mvn test -pl embedded-tests -am -Dtest='org.apache.druid.collections.CircularListTest,org.apache.druid.testing.embedded.query.SystemTableQueryTest' -Dsurefire.failIfNoSpecifiedTests=false -Pskip-static-checks -Dweb.console.skip=true -T1C

• Verified the effective embedded-tests Maven configuration supplies the flag to both Surefire and Docker-test Failsafe, and checked all four test argLine definitions.
• Java 25 Docker smoke checks confirmed direct and shell-launched JVMs report UseCompactObjectHeaders = true from the environment. Checked the revised single-build workflow shell syntax, Docker command arguments, and streamed Dockerfile contents.
• git diff --check and workflow shell syntax checks passed.
• Full unit, embedded, and Druid Docker regression suites remain for CI; the local Docker check used a Java smoke image, not a full Druid cluster.

This PR has:

• been self-reviewed.
• added a comment explaining the test image configuration.

[Copilot]

🟡 Changes recommended

The PR description/goal isn’t fully met because the processing module’s benchmark profile still overrides argLine without the compact headers flag, and the Dockerfile streaming step should use pipefail for reliability.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

This PR enables -XX:+UseCompactObjectHeaders across Druid’s test execution paths to surface regressions under JDK 25 compact object headers, including Maven test JVMs and the Docker distribution image used by CI docker-tests.

Changes:

• Add -XX:+UseCompactObjectHeaders to the parent Surefire argLine and the parallel-test profile override.
• Add the flag to the embedded Docker-test Failsafe argLine.
• Amend the docker-tests workflow build to append ENV JAVA_TOOL_OPTIONS="-XX:+UseCompactObjectHeaders" into the streamed Dockerfile used for the test image build.

File summaries

File	Description
pom.xml	Enables compact object headers for Maven Surefire test JVMs (default + parallel-test override).
embedded-tests/pom.xml	Enables compact object headers for embedded Docker-test Failsafe JVMs.
.github/workflows/docker-tests.yml	Injects JAVA_TOOL_OPTIONS into the test distribution image at build time for containerized JVMs.

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 2
• Review effort level: Lite

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[FrankChen021]

I have reviewed the code for correctness, edge cases, concurrency, and integration risks; no issues found.

Reviewed 3 of 3 changed files.

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This is an automated review by Codex GPT-5.6-Luna(max)