Use bundled Jupiter version for JUnit platform console standalone JARs

[wenytang-ms]

Summary

Fix JUnit 5/6 detection for junit-platform-console-standalone JARs whose manifest exposes different Platform and Jupiter engine versions.

Problem

junit-platform-console-standalone-1.13.4.jar contains JUnit Jupiter 5.13.4, but its manifest Specification-Version represents the JUnit Platform version (1.13.4), not the bundled Jupiter engine version.

CoreTestSearchEngine.hasJUnit5TestAnnotation() uses the resolved annotation type to inspect the containing JAR version. For standalone console JARs, reading Specification-Version causes the detected major version to be 1, so the JAR is not recognized as JUnit 5.

This can prevent a plain Eclipse Java project using junit-platform-console-standalone-1.13.4.jar from launching JUnit 5 tests correctly.

Fix

When the containing JAR is junit-platform-console-standalone-*, prefer the manifest attribute:

Engine-Version-junit-jupiter

and fall back to:

Specification-Version

for the existing non-standalone cases.

This keeps the existing annotation lookup and access-restriction behavior unchanged.

Behavior Matrix

Scenario	Before	After
Direct junit-jupiter-api-*.jar on classpath	Works	Works
junit-platform-console-standalone-1.13.4.jar with Jupiter 5.13.4	Detected as Platform 1.x, not JUnit 5	Detected as JUnit 5
junit-platform-console-standalone-6.0.3.jar	Detected as JUnit 6	Detected as JUnit 6
PDE forbidden/transitive JUnit dependency case from #2830/#2903	Access restrictions preserved	Access restrictions preserved

Tests

Added JUnitStandaloneDetectionTest covering:

• junit-platform-console-standalone-1.13.4.jar: Specification-Version=1.13.4, Engine-Version-junit-jupiter=5.13.4
• junit-platform-console-standalone-6.0.3.jar: Specification-Version=6.0.3, Engine-Version-junit-jupiter=6.0.3

Related

• Fixes: CoreTestSearchEngine.findAnnotations() fails to find @Testable in standalone/fat Multi-Release JARs #2959
• Downstream: Cannot run JUnit tests since v1.54.0 redhat-developer/vscode-java#4396
• Related: JUnit 4 test case is launched with JUnit 6 so no tests are ran #2830, TestKindRegistry.getContainerTestKindId detects the wrong JUnit type #2903

[wenytang-ms]

This patch intentionally handles the known JUnit Platform Console Standalone layout,
where Specification-Version represents the Platform version while
Engine-Version-junit-jupiter represents the bundled Jupiter version.

[wenytang-ms]

@trancexpress please help review this PR.

[iloveeclipse]

@wenytang-ms : to be clear, are you using latest 4.40 nightly build or are you using some older released Eclipse version? Latest nightly build is here: https://download.eclipse.org/eclipse/downloads/drops4/I20260426-1800/.

[wenytang-ms]

@wenytang-ms : to be clear, are you using latest 4.40 nightly build or are you using some older released Eclipse version? Latest nightly build is here: https://download.eclipse.org/eclipse/downloads/drops4/I20260426-1800/.

@iloveeclipse yes, I can repro such issue.

[trancexpress]

@wenytang-ms the PR looks great, please remove the merge commits and squash the remaining commits. Please also reword the commit message to reflect the current fix.

I tried to do this, but when setting the PR you've disabled editing by committers:

 ! [remote rejected]       findAnnotations-fat-jar-fallback -> findAnnotations-fat-jar-fallback (permission denied)

If you have future PRs, please amend and rebase for small changes like this. Generally only project branches have multiple commits. Normal PRs generally have 1 commit for the change and maybe the bot-generated bundle version bumps.

[wenytang-ms]

@wenytang-ms the PR looks great, please remove the merge commits and squash the remaining commits. Please also reword the commit message to reflect the current fix.

I tried to do this, but when setting the PR you've disabled editing by committers:

 ! [remote rejected]       findAnnotations-fat-jar-fallback -> findAnnotations-fat-jar-fallback (permission denied)

If you have future PRs, please amend and rebase for small changes like this. Generally only project branches have multiple commits. Normal PRs generally have 1 commit for the change and maybe the bot-generated bundle version bumps.

@trancexpress done

[trancexpress]

@wenytang-ms commit message is still outdated.

[wenytang-ms]

@wenytang-ms commit message is still outdated.

@trancexpress done

[trancexpress]

Thank you for the report and fix @wenytang-ms !