eclipse-lsp4e · FlorianKroiss · Apr 13, 2026
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
@@ -71,6 +71,12 @@ jobs:
         - windows-latest
         # https://github.com/actions/partner-runner-images
         - ubuntu-24.04-arm
+        target-platform:
+        - oldest
+        - latest
+        include:
+        - os: ubuntu-latest
+          target-platform: staging
     runs-on: ${{ matrix.os }}
     timeout-minutes: 20
 
@@ -160,10 +166,11 @@ jobs:
           ~/.m2/repository/.cache/tycho
           ~/.m2/repository/.meta/p2-artifacts.properties
           ~/.m2/repository/p2
-        key: ${{ runner.os }}-${{ runner.arch }}-repo-tycho-${{ hashFiles('target-platforms/target-platform-latest/target-platform-latest.target') }}
+        key: ${{ runner.os }}-${{ runner.arch }}-repo-tycho-${{ hashFiles(format('target-platforms/{0}.target', matrix.target-platform)) }}
 
 
     - name: "Build with Maven 🔨"
+      continue-on-error: ${{ matrix.target-platform == 'staging' }}
       uses: nick-fields/retry@v4
       with:
         max_attempts: 3
@@ -195,6 +202,7 @@ jobs:
             --errors \
             --update-snapshots \
             --batch-mode \
+            -Dlsp4e.targetPlatform=${{ matrix.target-platform }} \
             --show-version \
             -Declipse.p2.mirrors=false \
             -Dsurefire.rerunFailingTestsCount=3 \
@@ -215,7 +223,7 @@ jobs:
 
     - name: "Upload: Repository Zip"
       uses: actions/upload-artifact@v7
-      if: runner.os == 'Linux'
+      if: runner.os == 'Linux' && matrix.target-platform == 'oldest'
       with:
         name: org.eclipse.lsp4e.repository-${{matrix.target-platform}}-${{matrix.os}}
         path: repository/target/org.eclipse.lsp4e.repository-*.zip

diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
@@ -122,7 +122,7 @@ jobs:
           ~/.m2/repository/.cache/tycho
           ~/.m2/repository/.meta/p2-artifacts.properties
           ~/.m2/repository/p2
-        key: ${{ runner.os }}-${{ runner.arch }}-repo-tycho-${{ hashFiles('target-platforms/target-platform-latest/target-platform-latest.target') }}
+        key: ${{ runner.os }}-${{ runner.arch }}-repo-tycho-${{ hashFiles('target-platforms/oldest.target') }}
 
 
     # https://docs.github.com/en/code-security/code-scanning

diff --git a/.github/workflows/licensecheck.yml b/.github/workflows/licensecheck.yml
@@ -91,7 +91,7 @@ jobs:
           ~/.m2/repository/.cache/tycho
           ~/.m2/repository/.meta/p2-artifacts.properties
           ~/.m2/repository/p2
-        key: ${{ runner.os }}-${{ runner.arch }}-repo-tycho-${{ hashFiles('target-platforms/target-platform-latest/target-platform-latest.target') }}
+        key: ${{ runner.os }}-${{ runner.arch }}-repo-tycho-${{ hashFiles('target-platforms/oldest.target') }}
 
 
     - name: Dash License check  # see https://github.com/eclipse/dash-licenses

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -52,7 +52,7 @@ Latest snapshot builds, for testing, can usually be found at `https://download.e
 1. _File > Open Projects from Filesystem..._ , select the path to the LSP4E Git repo and the relevant children projects you want to import
 1. Depending on the task you're planning to work on, multiple workflows are available to configure the [target-platform](https://help.eclipse.org/latest/topic/org.eclipse.pde.doc.user/concepts/target.htm?cp=4_1_5)
     * In many cases, this simplest workflow will be sufficient: Install latest LSP4E snapshot in your target-platform (can be your current IDE), or
-    * If you don't want to mix versions of LSP4E, open [target-platforms/target-platform-latest/target-platform-latest.target](target-platforms/target-platform-latest/target-platform-latest.target) from within Eclipse and click **Set as Active Target-Platform** in the top right corner.
+    * If you don't want to mix versions of LSP4E, open [target-platforms/latest.target](target-platforms/latest.target) from within Eclipse and click **Set as Active Target-Platform** in the top right corner.
 1. Open the project modules you want to work on (right-click > Open project) and their dependencies
 1. Happy coding! 🤗
 

diff --git a/org.eclipse.lsp4e.test/META-INF/MANIFEST.MF b/org.eclipse.lsp4e.test/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: Tests for language server bundle (Incubation)
 Bundle-SymbolicName: org.eclipse.lsp4e.test;singleton:=true
-Bundle-Version: 0.16.9.qualifier
+Bundle-Version: 0.16.10.qualifier
 Fragment-Host: org.eclipse.lsp4e
 Bundle-Vendor: Eclipse LSP4E
 Bundle-RequiredExecutionEnvironment: JavaSE-21
@@ -30,8 +30,8 @@ Require-Bundle: org.eclipse.core.runtime,
  org.eclipse.e4.ui.workbench,
  org.eclipse.tm4e.ui,
  org.eclipse.core.filesystem,
- junit-jupiter-api;bundle-version="[6.0.1,7.0.0)",
- junit-jupiter-params;bundle-version="[6.0.1,7.0.0)",
+ junit-jupiter-api;bundle-version="[5.12.2,6.0.0)",
+ junit-jupiter-params;bundle-version="[5.12.2,6.0.0)",
  org.hamcrest,
  org.opentest4j
 Automatic-Module-Name: org.eclipse.lsp4e.test
diff --git a/org.eclipse.lsp4e.test/pom.xml b/org.eclipse.lsp4e.test/pom.xml
@@ -8,7 +8,7 @@
 	</parent>
 	<artifactId>org.eclipse.lsp4e.test</artifactId>
 	<packaging>eclipse-test-plugin</packaging>
-	<version>0.16.9-SNAPSHOT</version>
+	<version>0.16.10-SNAPSHOT</version>
 
 	<properties>
 		<os-jvm-flags /> <!-- for the default case -->
@@ -38,12 +38,15 @@
 				<version>${tycho-version}</version>
 				<!-- https://tycho.eclipseprojects.io/doc/latest/tycho-surefire-plugin/test-mojo.html -->
 				<configuration>
+					<systemProperties>
+						<!-- Set a system property, so we can disable some JUnit tests based on the current target platform -->
+						<lsp4e.targetPlatform>${lsp4e.targetPlatform}</lsp4e.targetPlatform>
+					</systemProperties>
 					<trimStackTrace>false</trimStackTrace>
 					<useUIHarness>true</useUIHarness>
 					<useUIThread>true</useUIThread>
 					<forkedProcessTimeoutInSeconds>1200</forkedProcessTimeoutInSeconds>
 					<argLine>-Dfile.encoding=${project.build.sourceEncoding} -Xms1g -Xmx1g -Djava.util.logging.config.file=${project.basedir}/src/jul.properties ${ui.test.vmargs} ${os-jvm-flags}</argLine>
-					<providerHint>junit6</providerHint>
 				</configuration>
 			</plugin>
 		</plugins>

diff --git a/org.eclipse.lsp4e.test/src/org/eclipse/lsp4e/test/codeactions/CodeActionTests.java b/org.eclipse.lsp4e.test/src/org/eclipse/lsp4e/test/codeactions/CodeActionTests.java
@@ -188,12 +188,9 @@ public void testCodeActionLiteralWorkspaceEdit() throws CoreException {
 	@Test
 	public void testNoCodeActionOnReadOnlySource() throws CoreException {
 		IFile f = TestUtils.createUniqueTestFile(project, "error");
-		f.setResourceAttributes(new ResourceAttributes() {
-			@Override
-			public boolean isReadOnly() {
-				return true;
-			}
-		});
+		ResourceAttributes attrs = f.getResourceAttributes();
+		attrs.setReadOnly(true);
+		f.setResourceAttributes(attrs);
 
 		final var tEdit = new TextEdit(new Range(new Position(0, 0), new Position(0, 5)), "fixed");
 		final var wEdit = new WorkspaceEdit(Collections.singletonMap(f.getLocationURI().toString(), List.of(tEdit)));

diff --git a/...lipse.lsp4e.test/src/org/eclipse/lsp4e/test/documentLink/DocumentLinkReconcilingTest.java b/...lipse.lsp4e.test/src/org/eclipse/lsp4e/test/documentLink/DocumentLinkReconcilingTest.java
@@ -37,6 +37,7 @@
 import org.eclipse.swt.custom.StyleRange;
 import org.eclipse.swt.graphics.Color;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledIfSystemProperty;
 
 public class DocumentLinkReconcilingTest extends AbstractTestWithProject {
 
@@ -188,6 +189,9 @@ public void testMidLineClippedDocumentLinkReconciling() throws Exception {
 	}
 
 	@Test
+	@DisabledIfSystemProperty(named = "lsp4e.targetPlatform", matches = "oldest", disabledReason = """
+			Fails on oldest target platform.
+			Note: this will only work when called from Maven or when setting the propery explicitly.""")
 	public void testClippedDocumentLinkReconciling() throws Exception {
 		MockLanguageServer.INSTANCE.setDocumentLinks(CONTENT_LINKS);
 

diff --git a/org.eclipse.lsp4e.test/src/org/eclipse/lsp4e/test/utils/AbstractTestWithProject.java b/org.eclipse.lsp4e.test/src/org/eclipse/lsp4e/test/utils/AbstractTestWithProject.java
@@ -15,6 +15,7 @@
 
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IResource;
+import org.eclipse.core.resources.ResourceAttributes;
 import org.eclipse.core.runtime.CoreException;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
@@ -53,6 +54,17 @@ private static void deleteProjectWithRetries(IProject project, int maxAttempts,
 				if (!project.exists()) {
 					break;
 				}
+				project.open(null);
+				project.accept(r -> {
+					ResourceAttributes attrs = r.getResourceAttributes();
+					// At least one test creates a read-only resource.
+					// This leads to errors when trying to delete the project, so we make all files writable again.
+					if (attrs != null && attrs.isReadOnly()) {
+						attrs.setReadOnly(false);
+						r.setResourceAttributes(attrs);
+					}
+					return true;
+				});
 				project.close(null);
 				project.delete(IResource.FORCE | IResource.ALWAYS_DELETE_PROJECT_CONTENT, null);
 				break;

diff --git a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/outline/CNFOutlinePage.java b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/outline/CNFOutlinePage.java
@@ -16,6 +16,7 @@
 import static org.eclipse.lsp4e.internal.NullSafetyHelper.castNullable;
 import static org.eclipse.lsp4e.internal.NullSafetyHelper.lateNonNull;
 
+import java.lang.reflect.InvocationTargetException;
 import java.util.ArrayList;
 
 import org.eclipse.core.runtime.Adapters;
@@ -54,7 +55,6 @@
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.ui.IActionBars;
 import org.eclipse.ui.navigator.CommonViewer;
-import org.eclipse.ui.navigator.CommonViewerComparator;
 import org.eclipse.ui.navigator.CommonViewerSorter;
 import org.eclipse.ui.texteditor.ITextEditor;
 import org.eclipse.ui.views.contentoutline.IContentOutlinePage;
@@ -77,8 +77,8 @@
 
 	private final LanguageServerWrapper wrapper;
 
-	@Nullable
-	private static Boolean canUseCommonViewerComparator;
+	private static @Nullable Class<?> comparatorClass = null;
+	private static boolean checkedForComparatorClass = false;
 
 	public CNFOutlinePage(LanguageServerWrapper wrapper, @Nullable ITextEditor textEditor) {
 		preferences = InstanceScope.INSTANCE.getNode(LanguageServerPlugin.PLUGIN_ID);
@@ -95,7 +95,7 @@
 		if (document != null) {
 			outlineViewer.setInput(new OutlineViewerInput(document, wrapper, textEditor));
 		}
-		outlineViewer.setComparator(createComparator());
+		configureSorterOrComparator(outlineViewer);
 		outlineViewer.getLabelProvider().addListener(this);
 		final var textEditor = this.textEditor;
 		if (textEditor != null) {
@@ -130,60 +130,34 @@
 	}
 
 	/**
-	 * Try to be compatible with older Eclipse versions (before 4.39) where
-	 * CommonViewerComparator is not available.
-	 *
-	 * @return comparator for the outline
-	 */
-	private static ViewerComparator createComparator() {
-		if (checkIfCommonViewerComparatorAvailable()) {
-			return Eclipse439PlusComparator.create();
-		}
-		return EclipseBefore439Comparator.create();
-	}
-
-	private static boolean checkIfCommonViewerComparatorAvailable() {
-		if(canUseCommonViewerComparator != null) {
-			return canUseCommonViewerComparator.booleanValue();
-		}
-		try {
-			Class.forName("org.eclipse.ui.navigator.CommonViewerComparator"); //$NON-NLS-1$
-			canUseCommonViewerComparator = Boolean.TRUE;
-			return true;
-		} catch (ClassNotFoundException e) {
-			canUseCommonViewerComparator = Boolean.FALSE;
-			return false;
-		}
-	}
-
-	/**
-	 * Compatible with modern Eclipse versions (4.39 and later) where
-	 * CommonViewerComparator is available.
-	 * <p>
-	 * This is extracted to an extra class to avoid classloading issues on older Eclipse versions where
-	 * the CommonViewerComparator class is not available. If we try to load a class referencing
-	 * CommonViewerComparator on an older Eclipse version, it will result in a ClassNotFoundException.
-	 *
-	 * @return comparator for the outline
+	 * Workaround for a Bug in Eclipse 4.39:
+	 * Before 4.39, the CommonViewerSorter can be used.
+	 * Starting with 4.39, using the CommonViewerSorter breaks sorting,
+	 * so the newer CommonViewerComparator must be used.
+	 * Once our oldest Target Platform contains CommonViewerComparator, we can drop this workaround.
+	 * @param viewer The viewer to configure
 	 */
-	private static final class Eclipse439PlusComparator {
-		static ViewerComparator create() {
-			return new CommonViewerComparator();
+	private void configureSorterOrComparator(CommonViewer viewer) {
+		if (!checkedForComparatorClass) {
+			checkedForComparatorClass = true;
+			try {
+				comparatorClass = Class.forName("org.eclipse.ui.navigator.CommonViewerComparator"); //$NON-NLS-1$
+			} catch (ClassNotFoundException e) {
+				// Will trigger on < 4.39.
+			}
 		}
-	}
 
-	/**
-	 * Compatible with older Eclipse versions (before 4.39) where
-	 * CommonViewerComparator is not available.
-	 * <p>
-	 * This is extracted to an extra class to avoid classloading issues
-	 *
-	 * @return comparator for the outline
-	 */
-	private static final class EclipseBefore439Comparator {
-		static ViewerComparator create() {
-			return new CommonViewerSorter();
+		if (comparatorClass != null) {
+			try {
+				ViewerComparator comparator = (ViewerComparator) comparatorClass.getDeclaredConstructor().newInstance();
+				viewer.setComparator(comparator);
+				return;
+			} catch (InstantiationException | IllegalAccessException | IllegalArgumentException
+					| InvocationTargetException | NoSuchMethodException | SecurityException e) {
+				// Fall-through
+			}
 		}
+		viewer.setSorter(new CommonViewerSorter());
 	}
 
 	/**

diff --git a/pom.xml b/pom.xml
@@ -15,6 +15,7 @@
 		<tycho.scmUrl>scm:git:https://github.com/eclipse-lsp4e/lsp4e.git</tycho.scmUrl>
 		<ui.test.vmargs></ui.test.vmargs>
 		<jgit.dirtyWorkingTree>error</jgit.dirtyWorkingTree>
+		<lsp4e.targetPlatform>oldest</lsp4e.targetPlatform>
 	</properties>
 
 	<organization>
@@ -75,7 +76,7 @@
 				<version>${tycho-version}</version>
 				<configuration>
 					<target>
-						<file>${maven.multiModuleProjectDirectory}/target-platforms/target-platform-latest/target-platform-latest.target</file>
+						<file>${maven.multiModuleProjectDirectory}/target-platforms/${lsp4e.targetPlatform}.target</file>
 					</target>
 					<environments>
 						<environment>

diff --git a/...form-latest/target-platform-latest.target → target-platforms/latest.target b/...form-latest/target-platform-latest.target → target-platforms/latest.target
@@ -13,10 +13,10 @@
     <location includeAllPlatforms="false" includeConfigurePhase="true" includeMode="planner" includeSource="true" type="InstallableUnit">
       <unit id="org.eclipse.ui.tests.harness" version="0.0.0"/>
       <unit id="org.eclipse.sdk.ide" version="0.0.0"/>
-      <repository location="https://download.eclipse.org/eclipse/updates/latest/"/>
+      <repository location="https://download.eclipse.org/eclipse/updates/4.39/"/>
     </location>
     <location type="InstallableUnit" includeConfigurePhase="true" includeMode="planner" includeSource="true">
-      <repository location="https://download.eclipse.org/tools/orbit/simrel/orbit-aggregation/release/latest"/>
+      <repository location="https://download.eclipse.org/tools/orbit/simrel/orbit-aggregation/release/4.39.0/"/>
       <unit id="org.commonmark" version="0.0.0"/>
       <unit id="org.commonmark.ext-gfm-tables" version="0.0.0"/>
       <unit id="com.google.guava" version="0.0.0"/>

diff --git a/target-platforms/oldest.target b/target-platforms/oldest.target
@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<?pde version="3.8"?>
+<target name="LSP4E Target-platform" sequenceNumber="1473749311">
+  <locations>
+    <location includeAllPlatforms="false" includeConfigurePhase="true" includeMode="planner" includeSource="true" type="InstallableUnit">
+      <unit id="org.eclipse.lsp4j" version="0.0.0"/>
+      <unit id="org.eclipse.lsp4j.jsonrpc" version="0.0.0"/>
+      <unit id="org.eclipse.lsp4j.debug" version="0.0.0"/>
+      <unit id="org.eclipse.lsp4j.jsonrpc.debug" version="0.0.0"/>
+      <unit id="com.google.gson" version="0.0.0"/>
+      <repository location="https://download.eclipse.org/lsp4j/updates/releases/1.0.0/"/>
+    </location>
+    <location includeAllPlatforms="false" includeConfigurePhase="true" includeMode="planner" includeSource="true" type="InstallableUnit">
+      <unit id="org.eclipse.ui.tests.harness" version="0.0.0"/>
+      <unit id="org.eclipse.sdk.ide" version="0.0.0"/>
+      <repository location="https://download.eclipse.org/eclipse/updates/4.37/"/>
+    </location>
+    <location type="InstallableUnit" includeConfigurePhase="true" includeMode="planner" includeSource="true">
+      <repository location="https://download.eclipse.org/tools/orbit/simrel/orbit-aggregation/release/4.37.0/"/>
+      <unit id="org.commonmark" version="0.0.0"/>
+      <unit id="org.commonmark.ext-gfm-tables" version="0.0.0"/>
+      <unit id="com.google.guava" version="0.0.0"/>
+      <unit id="com.google.guava.failureaccess" version="0.0.0"/>
+    </location>
+    <location includeAllPlatforms="false" includeConfigurePhase="false" includeMode="planner" includeSource="true" type="InstallableUnit">
+      <unit id="org.eclipse.tm4e.feature.feature.group" version="0.0.0"/>
+      <repository location="https://download.eclipse.org/tm4e/releases/latest/"/>
+    </location>
+    <location includeDependencyDepth="none" includeSource="false" missingManifest="error" type="Maven">
+      <dependencies>
+        <dependency>
+          <!-- External Eclipse null Annotations, see https://github.com/vegardit/no-npe -->
+          <groupId>com.vegardit.no-npe</groupId>
+          <artifactId>no-npe-eea-all</artifactId>
+          <version>1.3.9</version>
+          <type>jar</type>
+        </dependency>
+      </dependencies>
+    </location>
+    </locations>
+  <targetJRE path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-21"/>
+</target>