feat: upgrade to JUnit 6 + Eclipse 4.39 (simrel 2026-03) — milestone Xtext

End-to-end JUnit 6 + Eclipse 4.39 upgrade. Verified locally:
357 tests, 0 failures, 0 errors. The OSGi runtime contains only
JUnit 6.0.3 bundles (no JUnit 5.14.x, no jdt.junit5.runtime).

Two layers of dual-version JUnit pollution had to be peeled back:

1. Eclipse PDE umbrella feature transitively pulls jdt.junit5.runtime
   (strict-pinned to JUnit 5.14.x). Workaround: replace
   org.eclipse.pde.feature.group in the target with a curated bundle
   list of the six PDE bundles DDK uses (pde.core, pde.ui,
   pde.ua.core, pde.junit.runtime, jdt.junit.runtime, jdt.annotation).
   Verified load-bearing: dropping the curated list and going back to
   pde.feature.group makes target resolution unsatisfiable.

2. Xtext 2.42.0's org.eclipse.xtext.testing hard-pins
   org.junit.jupiter.api [5.1.0,6.0.0). Fix: eclipse-xtext/xtext#3660
   "Junit 6 support" landed in Xtext 2.43.0. This branch points at
   the 2.43.0.M2 milestone; a one-line follow-up PR will flip the
   URL to releases/2.43.0/ once stable ships on 2026-05-25.

Branch convention exception: this PR uses an Xtext milestone URL
rather than a stable release. The standing project rule is
stable-only. The exception is narrow: blocker fully understood,
upstream fix confirmed in M2, stable date on the horizon, and a
follow-up PR is planned to swap to stable.

Other target file changes:
  - sequenceNumber 28 -> 29
  - Eclipse SDK location updates/4.34/ -> releases/2026-03/
  - Source-feature IUs (platform.source.feature.group, jdt.source.*,
    pde.source.*) dropped — renamed in modern simrels and not needed
    for headless Tycho test runs.
  - swtbot.junit5.feature.group dropped — its feature.xml requires
    the JUnit 4 'org.junit' bundle which is no longer in the target,
    and DDK doesn't use SWTBotJunit5Extension (verified via static
    analysis).
  - orbit-aggregation 4.37.0 -> 4.39.0 with JUnit 6.0.3 IUs and
    dep versions back to 4.39-era (mockito 5.21.0, byte-buddy
    1.18.5, objenesis 3.5.0, commons-lang3 3.20.0, commons-text
    1.15.0, log4j 2.25.3).

xtext.test/pom.xml:
  - <providerHint>junit5</providerHint> -> <providerHint>junit6</providerHint>
  - extraRequirements: replaced the org.eclipse.pde feature requirement
    with an explicit org.eclipse.pde.junit.runtime plugin requirement

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: joaodinissf

com.avaloq.tools.ddk.xtext.test/pom.xml

@@ -19,6 +19,7 @@
         <configuration>
           <trimStackTrace>false</trimStackTrace>
           <skip>false</skip>
+          <providerHint>junit6</providerHint>
           <testClass>${test.testClass}</testClass>
           <failIfNoTests>false</failIfNoTests>
           <useUIThread>false</useUIThread>
@@ -48,9 +49,15 @@
                 <id>org.eclipse.xtext.sdk</id>
                 <versionRange>0.0.0</versionRange>
               </requirement>
+              <!--
+                org.eclipse.pde feature group is replaced in ddk-target/ddk.target by an
+                explicit list of pde.core / pde.ui / pde.ua.core / pde.junit.runtime so we
+                avoid pulling jdt.junit5.runtime (which strict-pins JUnit 5.14.x and conflicts
+                with our JUnit 6 stack).
+              -->
               <requirement>
-                <type>eclipse-feature</type>
-                <id>org.eclipse.pde</id>
+                <type>eclipse-plugin</type>
+                <id>org.eclipse.pde.junit.runtime</id>
                 <versionRange>0.0.0</versionRange>
               </requirement>
               <requirement>

ddk-target/ddk.target

@@ -1,20 +1,29 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde version="3.8"?>
-<target name="DDK Target" sequenceNumber="28">
+<target name="DDK Target" sequenceNumber="29">
 <locations>
   <location includeAllPlatforms="false" includeConfigurePhase="true" includeMode="planner" includeSource="true" type="InstallableUnit">
   <unit id="org.eclipse.swtbot.eclipse.feature.group" version="0.0.0"/>
   <unit id="org.eclipse.swtbot.feature.group" version="0.0.0"/>
   <unit id="org.eclipse.swtbot.ide.feature.group" version="0.0.0"/>
-  <unit id="org.eclipse.swtbot.junit5.feature.group" version="0.0.0"/>
   <repository location="http://download.eclipse.org/technology/swtbot/releases/4.2.1/"/>
   </location>
   <location includeAllPlatforms="false" includeConfigurePhase="true" includeMode="planner" includeSource="true" type="InstallableUnit">
-    <unit id="org.eclipse.pde.source.feature.group" version="0.0.0"/>
-    <unit id="org.eclipse.jdt.source.feature.group" version="0.0.0"/>
+    <!-- Curated bundle list instead of org.eclipse.pde.feature.group: that aggregator pulls
+         BOTH org.eclipse.jdt.junit5.runtime (which strict-pins JUnit 5.14.x) AND
+         org.eclipse.jdt.junit6.runtime (JUnit 6.x), producing the dual-version pollution
+         that crashed test discovery in PR #1292's silent-zero. The bundles below are the
+         minimum DDK actually uses (verified via static analysis of all MANIFEST.MFs and
+         src/ Java/Xtend imports); pde.junit.runtime + jdt.junit.runtime supply the OSGi-side
+         test launcher and depend only on the version-agnostic jdt.junit.runtime base. -->
     <unit id="org.eclipse.platform.feature.group" version="0.0.0"/>
-    <unit id="org.eclipse.platform.source.feature.group" version="0.0.0"/>
-    <repository location="https://download.eclipse.org/eclipse/updates/4.34/"/>
+    <unit id="org.eclipse.pde.core" version="0.0.0"/>
+    <unit id="org.eclipse.pde.ui" version="0.0.0"/>
+    <unit id="org.eclipse.pde.ua.core" version="0.0.0"/>
+    <unit id="org.eclipse.pde.junit.runtime" version="0.0.0"/>
+    <unit id="org.eclipse.jdt.junit.runtime" version="0.0.0"/>
+    <unit id="org.eclipse.jdt.annotation" version="0.0.0"/>
+    <repository location="https://download.eclipse.org/releases/2026-03/"/>
   </location>
   <location includeAllPlatforms="false" includeConfigurePhase="false" includeMode="planner" includeSource="true" type="InstallableUnit">
   <unit id="org.eclipse.emf.sdk.feature.group" version="0.0.0"/>
@@ -35,32 +44,37 @@
     <unit id="org.eclipse.xtend.sdk.feature.group" version="0.0.0"/>
     <unit id="org.eclipse.xtext.sdk.feature.group" version="0.0.0"/>
     <unit id="org.eclipse.xtext.xtext.generator" version="0.0.0"/>
-    <repository location="https://download.eclipse.org/modeling/tmf/xtext/updates/releases/2.42.0/"/>
+    <!-- TEMPORARY: Xtext 2.43.0.M2 milestone (stable 2.43.0 due 2026-05-25). 2.43.0 is the
+         first Xtext release with JUnit 6 support (issue eclipse-xtext/xtext#3660). The 2.42.0
+         release (2026-02) hard-pins org.junit.jupiter.api [5.1.0,6.0.0), which is the upstream
+         blocker we hit during step 4 iterations. Switch back to a stable release URL once
+         2.43.0 stable is available. -->
+    <repository location="https://download.eclipse.org/modeling/tmf/xtext/updates/milestones/2.43.0.M2/"/>
   </location>
   <location includeAllPlatforms="false" includeConfigurePhase="false" includeMode="planner" includeSource="true" type="InstallableUnit">
     <repository location="https://download.eclipse.org/lsp4j/updates/releases/1.0.0/"/>
     <unit id="org.eclipse.lsp4j.sdk.feature.group" version="0.0.0"/>
   </location>
   <location includeAllPlatforms="false" includeConfigurePhase="true" includeMode="planner" includeSource="true" type="InstallableUnit">
-    <repository location="https://download.eclipse.org/tools/orbit/simrel/orbit-aggregation/release/4.37.0"/>
-    <unit id="net.bytebuddy.byte-buddy" version="1.17.7"/>
-    <unit id="org.objenesis" version="3.4.0"/>
-    <unit id="org.mockito.mockito-core" version="5.19.0"/>
+    <repository location="https://download.eclipse.org/tools/orbit/simrel/orbit-aggregation/release/4.39.0"/>
+    <unit id="net.bytebuddy.byte-buddy" version="1.18.5"/>
+    <unit id="org.objenesis" version="3.5.0"/>
+    <unit id="org.mockito.mockito-core" version="5.21.0"/>
     <unit id="org.hamcrest" version="2.2.0"/>
     <unit id="org.apache.commons.logging" version="1.2.0"/>
-    <unit id="org.apache.commons.text" version="1.14.0"/>
-    <unit id="org.apache.commons.lang3" version="3.18.0"/>
-    <unit id="org.apache.logging.log4j.core" version="2.25.1"/>
-    <unit id="org.apache.logging.log4j.api" version="2.25.1"/>
+    <unit id="org.apache.commons.text" version="1.15.0"/>
+    <unit id="org.apache.commons.lang3" version="3.20.0"/>
+    <unit id="org.apache.logging.log4j.core" version="2.25.3"/>
+    <unit id="org.apache.logging.log4j.api" version="2.25.3"/>
     <unit id="org.apache.log4j" version="1.2.26"/> <!--use reload4j 1.2.26 for org.eclipse.xtext dependencies to log4j-->
-    <unit id="junit-jupiter-api" version="5.13.4"/>
-    <unit id="junit-jupiter-engine" version="5.13.4"/>
-    <unit id="junit-jupiter-params" version="5.13.4"/>
-    <unit id="junit-platform-commons" version="1.13.4"/>
-    <unit id="junit-platform-engine" version="1.13.4"/>
-    <unit id="junit-platform-launcher" version="1.13.4"/>
-    <unit id="junit-platform-suite-api" version="1.13.4"/>
-    <unit id="junit-platform-suite-engine" version="1.13.4"/>
+    <unit id="junit-jupiter-api" version="6.0.3"/>
+    <unit id="junit-jupiter-engine" version="6.0.3"/>
+    <unit id="junit-jupiter-params" version="6.0.3"/>
+    <unit id="junit-platform-commons" version="6.0.3"/>
+    <unit id="junit-platform-engine" version="6.0.3"/>
+    <unit id="junit-platform-launcher" version="6.0.3"/>
+    <unit id="junit-platform-suite-api" version="6.0.3"/>
+    <unit id="junit-platform-suite-engine" version="6.0.3"/>
   </location>
 </locations>
 </target>