Add classpathDependencies option for target platform resolution

   Adds a new <classpathDependencies> configuration option under
   <dependency-resolution> in target-platform-configuration with values
   require (default), optional, and ignore. This controls how
   jars.extra.classpath entries from build.properties are handled during
   resolution, fixing issues where platform-specific extra classpath
   entries cause resolution failures (e.g. SWT SVG fragment).

Author: laeubi

target-platform-configuration/src/main/java/org/eclipse/tycho/target/DependencyResolutionConfiguration.java

@@ -13,6 +13,7 @@
 import java.util.Properties;
 
 import org.apache.maven.plugins.annotations.Parameter;
+import org.eclipse.tycho.ClasspathDependenciesAction;
 import org.eclipse.tycho.OptionalResolutionAction;
 import org.eclipse.tycho.core.TargetPlatformConfiguration.LocalArtifactHandling;
 import org.eclipse.tycho.core.resolver.DefaultTargetPlatformConfigurationReader;
@@ -27,6 +28,7 @@ public class ExtraRequirementConfiguration {
     }
 
     public OptionalResolutionAction optionalDependencies;
+    public ClasspathDependenciesAction classpathDependencies;
     public List<ExtraRequirementConfiguration> extraRequirements;
     public Properties profileProperties;
     @Parameter(property = DefaultTargetPlatformConfigurationReader.LOCAL_ARTIFACTS_PROPERTY, name = DefaultTargetPlatformConfigurationReader.LOCAL_ARTIFACTS)

tycho-api/src/main/java/org/eclipse/tycho/ClasspathDependenciesAction.java

@@ -0,0 +1,36 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Christoph Läubrich and others.
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *    Christoph Läubrich - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.tycho;
+
+/**
+ * Defines how extra classpath dependencies (from <code>jars.extra.classpath</code> in
+ * build.properties) are handled during target platform resolution.
+ */
+public enum ClasspathDependenciesAction {
+
+    /**
+     * Treat extra classpath dependencies as required.
+     */
+    REQUIRE,
+
+    /**
+     * Treat extra classpath dependencies as optional (included if available, not an error if
+     * missing).
+     */
+    OPTIONAL,
+
+    /**
+     * Ignore extra classpath dependencies during resolution.
+     */
+    IGNORE;
+}

tycho-core/src/main/java/org/eclipse/tycho/core/TargetPlatformConfiguration.java

@@ -36,6 +36,7 @@
 import org.eclipse.equinox.p2.metadata.IRequirement;
 import org.eclipse.tycho.ArtifactKey;
 import org.eclipse.tycho.ArtifactType;
+import org.eclipse.tycho.ClasspathDependenciesAction;
 import org.eclipse.tycho.DefaultArtifactKey;
 import org.eclipse.tycho.OptionalResolutionAction;
 import org.eclipse.tycho.TargetEnvironment;
@@ -123,6 +124,8 @@ public enum InjectP2MavenMetadataHandling {
 
     private OptionalResolutionAction optionalAction = OptionalResolutionAction.REQUIRE;
 
+    private ClasspathDependenciesAction classpathDependenciesAction = ClasspathDependenciesAction.REQUIRE;
+
     private final List<ArtifactKey> extraRequirements = new ArrayList<>();
     private final Set<String> exclusions = new HashSet<>();
 
@@ -300,6 +303,14 @@ public void setOptionalResolutionAction(OptionalResolutionAction optionalAction)
         this.optionalAction = optionalAction;
     }
 
+    public ClasspathDependenciesAction getClasspathDependenciesAction() {
+        return classpathDependenciesAction;
+    }
+
+    public void setClasspathDependenciesAction(ClasspathDependenciesAction classpathDependenciesAction) {
+        this.classpathDependenciesAction = classpathDependenciesAction;
+    }
+
     /**
      * Returns the properties to be used for evaluating filters during dependency resolution.
      */

tycho-core/src/main/java/org/eclipse/tycho/core/resolver/AdditionalBundleRequirementsInstallableUnitProvider.java

@@ -34,8 +34,10 @@
 import org.eclipse.equinox.p2.metadata.VersionRange;
 import org.eclipse.tycho.BuildProperties;
 import org.eclipse.tycho.BuildPropertiesParser;
+import org.eclipse.tycho.ClasspathDependenciesAction;
 import org.eclipse.tycho.ReactorProject;
 import org.eclipse.tycho.TychoConstants;
+import org.eclipse.tycho.core.TargetPlatformConfiguration;
 import org.eclipse.tycho.core.TychoProjectManager;
 import org.eclipse.tycho.core.osgitools.DefaultReactorProject;
 import org.eclipse.tycho.p2maven.tmp.BundlesAction;
@@ -80,10 +82,18 @@ public Collection<IInstallableUnit> getInstallableUnits(MavenProject project, Ma
             //"classic" pde project with build properties
             ReactorProject reactorProject = DefaultReactorProject.adapt(project);
             BuildProperties buildProperties = buildPropertiesParser.parse(reactorProject);
-            Stream<IRequirement> extraClassPath = buildProperties.getJarsExtraClasspath().stream()
-                    .map(TychoConstants.PLATFORM_URL_PATTERN::matcher).filter(Matcher::matches)
-                    .map(m -> MetadataFactory.createRequirement(BundlesAction.CAPABILITY_NS_OSGI_BUNDLE, m.group(2),
-                            VersionRange.emptyRange, null, true, false));
+            TargetPlatformConfiguration tpConfig = projectManager.getTargetPlatformConfiguration(project);
+            ClasspathDependenciesAction classpathAction = tpConfig.getClasspathDependenciesAction();
+            Stream<IRequirement> extraClassPath;
+            if (classpathAction == ClasspathDependenciesAction.IGNORE) {
+                extraClassPath = Stream.empty();
+            } else {
+                boolean optional = classpathAction == ClasspathDependenciesAction.OPTIONAL;
+                extraClassPath = buildProperties.getJarsExtraClasspath().stream()
+                        .map(TychoConstants.PLATFORM_URL_PATTERN::matcher).filter(Matcher::matches)
+                        .map(m -> MetadataFactory.createRequirement(BundlesAction.CAPABILITY_NS_OSGI_BUNDLE,
+                                m.group(2), VersionRange.emptyRange, null, optional, false));
+            }
             Stream<IRequirement> additionalBundles = buildProperties.getAdditionalBundles().stream()
                     .map(bundleName -> MetadataFactory.createRequirement(BundlesAction.CAPABILITY_NS_OSGI_BUNDLE,
                             bundleName, VersionRange.emptyRange, null, true, false));

tycho-core/src/main/java/org/eclipse/tycho/core/resolver/DefaultTargetPlatformConfigurationReader.java

@@ -36,6 +36,7 @@
 import org.codehaus.plexus.logging.Logger;
 import org.codehaus.plexus.util.xml.Xpp3Dom;
 import org.eclipse.tycho.BuildFailureException;
+import org.eclipse.tycho.ClasspathDependenciesAction;
 import org.eclipse.tycho.DefaultArtifactKey;
 import org.eclipse.tycho.OptionalResolutionAction;
 import org.eclipse.tycho.TargetEnvironment;
@@ -65,6 +66,7 @@ public class DefaultTargetPlatformConfigurationReader {
     public static final String REFERENCED_REPOSITORY_MODE = "referencedRepositoryMode";
     public static final String DEPENDENCY_RESOLUTION = "dependency-resolution";
     public static final String OPTIONAL_DEPENDENCIES = "optionalDependencies";
+    public static final String CLASSPATH_DEPENDENCIES = "classpathDependencies";
     public static final String LOCAL_ARTIFACTS = "localArtifacts";
     public static final String LOCAL_ARTIFACTS_PROPERTY = "tycho.localArtifacts";
 
@@ -217,6 +219,7 @@ protected void readDependencyResolutionConfiguration(TargetPlatformConfiguration
         }
 
         setOptionalDependencies(result, resolverDom);
+        setClasspathDependencies(result, resolverDom);
         setLocalArtifacts(result, resolverDom, mavenSession);
         readExtraRequirements(result, resolverDom);
         readProfileProperties(result, resolverDom);
@@ -263,6 +266,21 @@ private void setOptionalDependencies(TargetPlatformConfiguration result, Xpp3Dom
         }
     }
 
+    private void setClasspathDependencies(TargetPlatformConfiguration result, Xpp3Dom resolverDom) {
+        String value = getStringValue(resolverDom.getChild(CLASSPATH_DEPENDENCIES));
+
+        if (value == null) {
+            return;
+        }
+        try {
+            result.setClasspathDependenciesAction(ClasspathDependenciesAction.valueOf(value.toUpperCase()));
+        } catch (IllegalArgumentException e) {
+            throw new BuildFailureException("Illegal value of <" + CLASSPATH_DEPENDENCIES
+                    + "> dependency resolution parameter: " + value + ", allowed values are: "
+                    + Arrays.toString(ClasspathDependenciesAction.values()));
+        }
+    }
+
     protected void readExtraRequirements(TargetPlatformConfiguration result, Xpp3Dom resolverDom)
             throws BuildFailureException {
         Xpp3Dom requirementsDom = resolverDom.getChild("extraRequirements");