diff --git a/variants/src/main/java/org/implab/gradle/variants/VariantSourcesPlugin.java b/variants/src/main/java/org/implab/gradle/variants/VariantSourcesPlugin.java
--- a/variants/src/main/java/org/implab/gradle/variants/VariantSourcesPlugin.java
+++ b/variants/src/main/java/org/implab/gradle/variants/VariantSourcesPlugin.java
@@ -16,8 +16,8 @@ import org.implab.gradle.variants.core.V
 import org.implab.gradle.variants.core.VariantsExtension;
 import org.implab.gradle.variants.core.VariantsView;
 import org.implab.gradle.variants.sources.CompileUnit;
+import org.implab.gradle.variants.sources.CompileUnitSourceSetSpec;
 import org.implab.gradle.variants.sources.CompileUnitsView;
-import org.implab.gradle.variants.sources.GenericSourceSet;
 import org.implab.gradle.variants.sources.RoleProjectionsView;
 import org.implab.gradle.variants.sources.VariantSourcesContext;
 import org.implab.gradle.variants.sources.VariantSourcesExtension;
@@ -92,7 +92,7 @@ public abstract class VariantSourcesPlug
             }
 
             @Override
-            public void variant(String variantName, Action<? super GenericSourceSet> action) {
+            public void variant(String variantName, Action<? super CompileUnitSourceSetSpec> action) {
                 Strings.argumentNotNullOrBlank(variantName, "variantName");
                 Objects.requireNonNull(action, "action can't be null");
 
@@ -102,7 +102,7 @@ public abstract class VariantSourcesPlug
             }
 
             @Override
-            public void layer(String layerName, Action<? super GenericSourceSet> action) {
+            public void layer(String layerName, Action<? super CompileUnitSourceSetSpec> action) {
                 // protect external DSL
                 Strings.argumentNotNullOrBlank(layerName, "layerName");
                 Objects.requireNonNull(action, "action can't be null");
@@ -113,7 +113,7 @@ public abstract class VariantSourcesPlug
             }
 
             @Override
-            public void unit(String variantName, String layerName, Action<? super GenericSourceSet> action) {
+            public void unit(String variantName, String layerName, Action<? super CompileUnitSourceSetSpec> action) {
                 Strings.argumentNotNullOrBlank(layerName, "layerName");
                 Strings.argumentNotNullOrBlank(variantName, "variantName");
                 Objects.requireNonNull(action, "action can't be null");
@@ -122,6 +122,15 @@ public abstract class VariantSourcesPlug
 
                 whenAvailable(ctx -> ctx.configureUnit(resolveCompileUnit(ctx, variantName, layerName), action));
             }
+
+            @Override
+            public void configureEach(Action<? super CompileUnitSourceSetSpec> action) {
+                Objects.requireNonNull(action, "action can't be null");
+
+                lateConfigurationPolicy.finalizePolicy();
+
+                whenAvailable(ctx -> ctx.configureEach(action));
+            }
         };
 
         extensions.add(VariantSourcesExtension.class, VARIANT_SOURCES_EXTENSION, variantSourcesExtension);
diff --git a/variants/src/main/java/org/implab/gradle/variants/sources/CompileUnitSourceSetSpec.java b/variants/src/main/java/org/implab/gradle/variants/sources/CompileUnitSourceSetSpec.java
new file mode 100644
--- /dev/null
+++ b/variants/src/main/java/org/implab/gradle/variants/sources/CompileUnitSourceSetSpec.java
@@ -0,0 +1,69 @@
+package org.implab.gradle.variants.sources;
+
+import org.gradle.api.Action;
+import org.implab.gradle.common.core.lang.Closures;
+import org.implab.gradle.variants.core.Layer;
+import org.implab.gradle.variants.core.Variant;
+
+import groovy.lang.Closure;
+
+/**
+ * Source-set materialization context for one compile unit.
+ *
+ * <p>This type keeps compile-unit identity next to the materialized
+ * {@link GenericSourceSet} without turning the selector DSL into a second
+ * source-set API. Use {@link #getCompileUnit()} for selection metadata and
+ * {@link #sourceSet(Action)} when the underlying source set body must be
+ * configured.
+ */
+public interface CompileUnitSourceSetSpec {
+    /**
+     * Returns the compile unit represented by this source set.
+     *
+     * @return compile-unit identity
+     */
+    CompileUnit getCompileUnit();
+
+    /**
+     * Returns the variant part of the compile-unit identity.
+     *
+     * @return variant identity
+     */
+    default Variant getVariant() {
+        return getCompileUnit().variant();
+    }
+
+    /**
+     * Returns the layer part of the compile-unit identity.
+     *
+     * @return layer identity
+     */
+    default Layer getLayer() {
+        return getCompileUnit().layer();
+    }
+
+    /**
+     * Returns the materialized source set body.
+     *
+     * @return source set body
+     */
+    GenericSourceSet getSourceSet();
+
+    /**
+     * Configures the materialized source set body.
+     *
+     * @param action source set configuration action
+     */
+    default void sourceSet(Action<? super GenericSourceSet> action) {
+        action.execute(getSourceSet());
+    }
+
+    /**
+     * Configures the materialized source set body.
+     *
+     * @param closure source set configuration closure
+     */
+    default void sourceSet(Closure<?> closure) {
+        sourceSet(Closures.action(closure));
+    }
+}
diff --git a/variants/src/main/java/org/implab/gradle/variants/sources/GenericSourceSet.java b/variants/src/main/java/org/implab/gradle/variants/sources/GenericSourceSet.java
--- a/variants/src/main/java/org/implab/gradle/variants/sources/GenericSourceSet.java
+++ b/variants/src/main/java/org/implab/gradle/variants/sources/GenericSourceSet.java
@@ -26,10 +26,6 @@ import org.gradle.api.file.ProjectLayout
 import org.gradle.api.file.SourceDirectorySet;
 import org.gradle.api.model.ObjectFactory;
 import org.gradle.api.tasks.TaskProvider;
-import org.gradle.util.Configurable;
-import org.implab.gradle.common.core.lang.Closures;
-
-import groovy.lang.Closure;
 
 /**
  * A configurable source set abstraction with named outputs.
@@ -50,8 +46,7 @@ import groovy.lang.Closure;
  * {@link InvalidUserDataException}.
  * </p>
  */
-public abstract class GenericSourceSet
-        implements Named, Configurable<GenericSourceSet> {
+public abstract class GenericSourceSet implements Named {
     private final String name;
 
     private final NamedDomainObjectContainer<SourceDirectorySet> sourceDirectorySets;
@@ -172,16 +167,6 @@ public abstract class GenericSourceSet
                 .builtBy(task);
     }
 
-    /**
-     * Applies a Groovy closure to this source set, enabling DSL-style
-     * configuration.
-     */
-    @Override
-    public GenericSourceSet configure(Closure configure) {
-        Closures.apply(configure, this);
-        return this;
-    }
-
     private SourceDirectorySet createSourceDirectorySet(String name) {
         return objects.sourceDirectorySet(name, name);
     }
diff --git a/variants/src/main/java/org/implab/gradle/variants/sources/VariantSourcesContext.java b/variants/src/main/java/org/implab/gradle/variants/sources/VariantSourcesContext.java
--- a/variants/src/main/java/org/implab/gradle/variants/sources/VariantSourcesContext.java
+++ b/variants/src/main/java/org/implab/gradle/variants/sources/VariantSourcesContext.java
@@ -35,7 +35,7 @@ public interface VariantSourcesContext {
     SourceSetMaterializer getSourceSets();
 
     /**
-     * Configures all GenericSourceSets produced from the given layer.
+     * Configures all source sets produced from the given layer.
      *
      * The action is applied:
      * - to already materialized source sets of this layer
@@ -52,10 +52,10 @@ public interface VariantSourcesContext {
      * @throws org.gradle.api.InvalidUserDataException if the layer is not part of
      *         the finalized variant model
      */
-    void configureLayer(Layer layer, Action<? super GenericSourceSet> action);
+    void configureLayer(Layer layer, Action<? super CompileUnitSourceSetSpec> action);
 
     /**
-     * Configures all GenericSourceSets produced from the given variant.
+     * Configures all source sets produced from the given variant.
      *
      * <p>Late application semantics for already materialized source sets are
      * governed by
@@ -64,10 +64,10 @@ public interface VariantSourcesContext {
      * @throws org.gradle.api.InvalidUserDataException if the variant is not part
      *         of the finalized variant model
      */
-    void configureVariant(Variant variant, Action<? super GenericSourceSet> action);
+    void configureVariant(Variant variant, Action<? super CompileUnitSourceSetSpec> action);
 
     /**
-     * Configures the GenericSourceSet produced from the given compile unit.
+     * Configures the source set produced from the given compile unit.
      *
      * <p>Late application semantics for already materialized source sets are
      * governed by
@@ -76,6 +76,18 @@ public interface VariantSourcesContext {
      * @throws org.gradle.api.InvalidUserDataException if the compile unit is not
      *         part of the finalized variant model
      */
-    void configureUnit(CompileUnit unit, Action<? super GenericSourceSet> action);
+    void configureUnit(CompileUnit unit, Action<? super CompileUnitSourceSetSpec> action);
+
+    /**
+     * Configures every source set materialized from the finalized compile-unit
+     * model.
+     *
+     * <p>This selector is applied before variant-, layer-, and unit-specific
+     * selectors.
+     *
+     * @throws org.gradle.api.InvalidUserDataException if late configuration is
+     *         rejected by the selected policy
+     */
+    void configureEach(Action<? super CompileUnitSourceSetSpec> action);
 
 }
diff --git a/variants/src/main/java/org/implab/gradle/variants/sources/VariantSourcesExtension.java b/variants/src/main/java/org/implab/gradle/variants/sources/VariantSourcesExtension.java
--- a/variants/src/main/java/org/implab/gradle/variants/sources/VariantSourcesExtension.java
+++ b/variants/src/main/java/org/implab/gradle/variants/sources/VariantSourcesExtension.java
@@ -10,7 +10,7 @@ public interface VariantSourcesExtension
 
     /**
      * Selects how selector rules behave when they target an already materialized
-     * {@link GenericSourceSet}.
+     * source set.
      *
      * <p>This policy is single-valued:
      * <ul>
@@ -64,7 +64,7 @@ public interface VariantSourcesExtension
      * {@link #lateConfigurationPolicy(Action)} for the remaining extension
      * lifecycle.
      */
-    void layer(String layerName, Action<? super GenericSourceSet> action);
+    void layer(String layerName, Action<? super CompileUnitSourceSetSpec> action);
 
     default void layer(String layerName, Closure<?> closure) {
         layer(layerName, Closures.action(closure));
@@ -77,7 +77,7 @@ public interface VariantSourcesExtension
      * {@link #lateConfigurationPolicy(Action)} for the remaining extension
      * lifecycle.
      */
-    void variant(String variantName, Action<? super GenericSourceSet> action);
+    void variant(String variantName, Action<? super CompileUnitSourceSetSpec> action);
 
     default void variant(String variantName, Closure<?> closure) {
         variant(variantName, Closures.action(closure));
@@ -90,13 +90,27 @@ public interface VariantSourcesExtension
      * {@link #lateConfigurationPolicy(Action)} for the remaining extension
      * lifecycle.
      */
-    void unit(String variantName, String layerName, Action<? super GenericSourceSet> action);
+    void unit(String variantName, String layerName, Action<? super CompileUnitSourceSetSpec> action);
 
     default void unit(String variantName, String layerName, Closure<?> closure) {
         unit(variantName, layerName, Closures.action(closure));
     }
 
     /**
+     * Registers a selector rule for every materialized compile-unit source set.
+     *
+     * <p>Registering the first selector rule fixes the selected
+     * {@link #lateConfigurationPolicy(Action)} for the remaining extension
+     * lifecycle. This selector is applied before variant-, layer-, and unit-specific
+     * selectors.
+     */
+    void configureEach(Action<? super CompileUnitSourceSetSpec> action);
+
+    default void configureEach(Closure<?> closure) {
+        configureEach(Closures.action(closure));
+    }
+
+    /**
      * Invoked when the variants-derived source context becomes available.
      *
      * Replayable:
diff --git a/variants/src/main/java/org/implab/gradle/variants/sources/internal/DefaultCompileUnitSourceSetSpec.java b/variants/src/main/java/org/implab/gradle/variants/sources/internal/DefaultCompileUnitSourceSetSpec.java
new file mode 100644
--- /dev/null
+++ b/variants/src/main/java/org/implab/gradle/variants/sources/internal/DefaultCompileUnitSourceSetSpec.java
@@ -0,0 +1,25 @@
+package org.implab.gradle.variants.sources.internal;
+
+import org.implab.gradle.variants.sources.CompileUnit;
+import org.implab.gradle.variants.sources.CompileUnitSourceSetSpec;
+import org.implab.gradle.variants.sources.GenericSourceSet;
+
+class DefaultCompileUnitSourceSetSpec implements CompileUnitSourceSetSpec {
+    private final CompileUnit compileUnit;
+    private final GenericSourceSet sourceSet;
+
+    DefaultCompileUnitSourceSetSpec(CompileUnit compileUnit, GenericSourceSet sourceSet) {
+        this.compileUnit = compileUnit;
+        this.sourceSet = sourceSet;
+    }
+
+    @Override
+    public CompileUnit getCompileUnit() {
+        return compileUnit;
+    }
+
+    @Override
+    public GenericSourceSet getSourceSet() {
+        return sourceSet;
+    }
+}
diff --git a/variants/src/main/java/org/implab/gradle/variants/sources/internal/DefaultVariantSourcesContext.java b/variants/src/main/java/org/implab/gradle/variants/sources/internal/DefaultVariantSourcesContext.java
--- a/variants/src/main/java/org/implab/gradle/variants/sources/internal/DefaultVariantSourcesContext.java
+++ b/variants/src/main/java/org/implab/gradle/variants/sources/internal/DefaultVariantSourcesContext.java
@@ -9,6 +9,7 @@ import org.implab.gradle.variants.core.L
 import org.implab.gradle.variants.core.Variant;
 import org.implab.gradle.variants.core.VariantsView;
 import org.implab.gradle.variants.sources.CompileUnit;
+import org.implab.gradle.variants.sources.CompileUnitSourceSetSpec;
 import org.implab.gradle.variants.sources.CompileUnitsView;
 import org.implab.gradle.variants.sources.GenericSourceSet;
 import org.implab.gradle.variants.sources.RoleProjectionsView;
@@ -62,26 +63,32 @@ public class DefaultVariantSourcesContex
     }
 
     @Override
-    public void configureLayer(Layer layer, Action<? super GenericSourceSet> action) {
+    public void configureLayer(Layer layer, Action<? super CompileUnitSourceSetSpec> action) {
         variantsView.assertLayer(layer);
         Objects.requireNonNull(action, "action can't be null");
         sourceSetConfigurationRegistry.addLayerAction(layer, action);
     }
 
     @Override
-    public void configureVariant(Variant variant, Action<? super GenericSourceSet> action) {
+    public void configureVariant(Variant variant, Action<? super CompileUnitSourceSetSpec> action) {
         variantsView.assertVariant(variant);
         Objects.requireNonNull(action, "action can't be null");
         sourceSetConfigurationRegistry.addVariantAction(variant, action);
     }
 
     @Override
-    public void configureUnit(CompileUnit unit, Action<? super GenericSourceSet> action) {
+    public void configureUnit(CompileUnit unit, Action<? super CompileUnitSourceSetSpec> action) {
         assertCompileUnit(unit);
         Objects.requireNonNull(action, "action can't be null");
         sourceSetConfigurationRegistry.addCompileUnitAction(unit, action);
     }
 
+    @Override
+    public void configureEach(Action<? super CompileUnitSourceSetSpec> action) {
+        Objects.requireNonNull(action, "action can't be null");
+        sourceSetConfigurationRegistry.addAction(action);
+    }
+
     private void assertCompileUnit(CompileUnit unit) {
         Objects.requireNonNull(unit, "unit can't be null");
         variantsView.assertVariant(unit.variant());
diff --git a/variants/src/main/java/org/implab/gradle/variants/sources/internal/SourceSetConfigurationRegistry.java b/variants/src/main/java/org/implab/gradle/variants/sources/internal/SourceSetConfigurationRegistry.java
--- a/variants/src/main/java/org/implab/gradle/variants/sources/internal/SourceSetConfigurationRegistry.java
+++ b/variants/src/main/java/org/implab/gradle/variants/sources/internal/SourceSetConfigurationRegistry.java
@@ -17,15 +17,17 @@ import org.implab.gradle.common.core.lan
 import org.implab.gradle.variants.core.Layer;
 import org.implab.gradle.variants.core.Variant;
 import org.implab.gradle.variants.sources.CompileUnit;
+import org.implab.gradle.variants.sources.CompileUnitSourceSetSpec;
 import org.implab.gradle.variants.sources.GenericSourceSet;
 
 @NonNullByDefault
 public class SourceSetConfigurationRegistry {
     private static final Logger logger = Logging.getLogger(SourceSetConfigurationRegistry.class);
 
-    private final Map<Layer, ReplayableQueue<GenericSourceSet>> sourcesByLayer = new LinkedHashMap<>();
-    private final Map<Variant, ReplayableQueue<GenericSourceSet>> sourcesByVariant = new LinkedHashMap<>();
-    private final Map<CompileUnit, ReplayableQueue<GenericSourceSet>> sourcesByUnit = new LinkedHashMap<>();
+    private final ReplayableQueue<CompileUnitSourceSetSpec> sources = new ReplayableQueue<>();
+    private final Map<Layer, ReplayableQueue<CompileUnitSourceSetSpec>> sourcesByLayer = new LinkedHashMap<>();
+    private final Map<Variant, ReplayableQueue<CompileUnitSourceSetSpec>> sourcesByVariant = new LinkedHashMap<>();
+    private final Map<CompileUnit, ReplayableQueue<CompileUnitSourceSetSpec>> sourcesByUnit = new LinkedHashMap<>();
 
     private final Supplier<LateConfigurationMode> lateConfigurationMode;
 
@@ -33,7 +35,14 @@ public class SourceSetConfigurationRegis
         this.lateConfigurationMode = lateConfigurationMode;
     }
 
-    public void addLayerAction(Layer layer, Action<? super GenericSourceSet> action) {
+    public void addAction(Action<? super CompileUnitSourceSetSpec> action) {
+        addToActions(
+                sources,
+                action,
+                "Source sets already materialized");
+    }
+
+    public void addLayerAction(Layer layer, Action<? super CompileUnitSourceSetSpec> action) {
         addToActions(
                 sourcesByLayer.computeIfAbsent(layer, key -> new ReplayableQueue<>()),
                 action,
@@ -42,7 +51,7 @@ public class SourceSetConfigurationRegis
                         layer.getName()));
     }
 
-    public void addVariantAction(Variant variant, Action<? super GenericSourceSet> action) {
+    public void addVariantAction(Variant variant, Action<? super CompileUnitSourceSetSpec> action) {
         addToActions(
                 sourcesByVariant.computeIfAbsent(variant, key -> new ReplayableQueue<>()),
                 action,
@@ -52,7 +61,7 @@ public class SourceSetConfigurationRegis
 
     }
 
-    public void addCompileUnitAction(CompileUnit unit, Action<? super GenericSourceSet> action) {
+    public void addCompileUnitAction(CompileUnit unit, Action<? super CompileUnitSourceSetSpec> action) {
         addToActions(
                 sourcesByUnit.computeIfAbsent(unit, key -> new ReplayableQueue<>()),
                 action,
@@ -63,18 +72,21 @@ public class SourceSetConfigurationRegis
     }
 
     private void addToActions(
-            ReplayableQueue<GenericSourceSet> actions,
-            Action<? super GenericSourceSet> action,
+            ReplayableQueue<CompileUnitSourceSetSpec> actions,
+            Action<? super CompileUnitSourceSetSpec> action,
             String assertMessage) {
         assertLazyConfiguration(actions.values(), assertMessage);
         actions.forEach(action::execute);
     }
 
-    void assertLazyConfiguration(List<GenericSourceSet> sets, String message) {
+    void assertLazyConfiguration(List<CompileUnitSourceSetSpec> sets, String message) {
         if (sets.size() == 0)
             return;
 
-        var names = sets.stream().map(Named::getName).collect(Collectors.joining(", "));
+        var names = sets.stream()
+                .map(CompileUnitSourceSetSpec::getSourceSet)
+                .map(Named::getName)
+                .collect(Collectors.joining(", "));
 
         switch (lateConfigurationMode.get()) {
             case FAIL:
@@ -88,8 +100,10 @@ public class SourceSetConfigurationRegis
     }
 
     public void applyConfiguration(CompileUnit unit, GenericSourceSet sourceSet) {
-        sourcesByVariant.computeIfAbsent(unit.variant(), key -> new ReplayableQueue<>()).add(sourceSet);
-        sourcesByLayer.computeIfAbsent(unit.layer(), key -> new ReplayableQueue<>()).add(sourceSet);
-        sourcesByUnit.computeIfAbsent(unit, key -> new ReplayableQueue<>()).add(sourceSet);
+        var spec = new DefaultCompileUnitSourceSetSpec(unit, sourceSet);
+        sources.add(spec);
+        sourcesByVariant.computeIfAbsent(unit.variant(), key -> new ReplayableQueue<>()).add(spec);
+        sourcesByLayer.computeIfAbsent(unit.layer(), key -> new ReplayableQueue<>()).add(spec);
+        sourcesByUnit.computeIfAbsent(unit, key -> new ReplayableQueue<>()).add(spec);
     }
 }
diff --git a/variants/src/test/java/org/implab/gradle/variants/VariantArtifactsPluginFunctionalTest.java b/variants/src/test/java/org/implab/gradle/variants/VariantArtifactsPluginFunctionalTest.java
--- a/variants/src/test/java/org/implab/gradle/variants/VariantArtifactsPluginFunctionalTest.java
+++ b/variants/src/test/java/org/implab/gradle/variants/VariantArtifactsPluginFunctionalTest.java
@@ -197,12 +197,16 @@ class VariantArtifactsPluginFunctionalTe
 
                 variantSources {
                     layer('mainBase') {
-                        declareOutputs('js')
-                        registerOutput('js', layout.projectDirectory.file('inputs/base.js'))
+                        sourceSet {
+                            declareOutputs('js')
+                            registerOutput('js', layout.projectDirectory.file('inputs/base.js'))
+                        }
                     }
                     layer('mainAmd') {
-                        declareOutputs('js')
-                        registerOutput('js', layout.projectDirectory.file('inputs/amd.js'))
+                        sourceSet {
+                            declareOutputs('js')
+                            registerOutput('js', layout.projectDirectory.file('inputs/amd.js'))
+                        }
                     }
                 }
 
@@ -349,7 +353,9 @@ class VariantArtifactsPluginFunctionalTe
                 }
 
                 variantSources.layer('main') {
-                    declareOutputs('types')
+                    sourceSet {
+                        declareOutputs('types')
+                    }
                 }
 
                 variantArtifacts {
@@ -432,8 +438,10 @@ class VariantArtifactsPluginFunctionalTe
                 }
 
                 variantSources.layer('main') {
-                    declareOutputs('js')
-                    registerOutput('js', layout.projectDirectory.file('inputs/base.js'))
+                    sourceSet {
+                        declareOutputs('js')
+                        registerOutput('js', layout.projectDirectory.file('inputs/base.js'))
+                    }
                 }
 
                 variantArtifacts {
@@ -528,7 +536,9 @@ class VariantArtifactsPluginFunctionalTe
                 }
 
                 variantSources.layer('main') {
-                    declareOutputs('types', 'js')
+                    sourceSet {
+                        declareOutputs('types', 'js')
+                    }
                 }
 
                 variantArtifacts {
@@ -616,9 +626,11 @@ class VariantArtifactsPluginFunctionalTe
                     }
 
                     variantSources.layer('main') {
-                        declareOutputs('types', 'js')
-                        registerOutput('types', layout.projectDirectory.file('inputs/types.d.ts'))
-                        registerOutput('js', layout.projectDirectory.file('inputs/index.js'))
+                        sourceSet {
+                            declareOutputs('types', 'js')
+                            registerOutput('types', layout.projectDirectory.file('inputs/types.d.ts'))
+                            registerOutput('js', layout.projectDirectory.file('inputs/index.js'))
+                        }
                     }
 
                     variantArtifacts {
diff --git a/variants/src/test/java/org/implab/gradle/variants/VariantSourcesPluginFunctionalTest.java b/variants/src/test/java/org/implab/gradle/variants/VariantSourcesPluginFunctionalTest.java
--- a/variants/src/test/java/org/implab/gradle/variants/VariantSourcesPluginFunctionalTest.java
+++ b/variants/src/test/java/org/implab/gradle/variants/VariantSourcesPluginFunctionalTest.java
@@ -95,14 +95,18 @@ class VariantSourcesPluginFunctionalTest
                 def events = []
 
                 variantSources {
+                    configureEach {
+                        events << "all:" + sourceSet.name
+                        events << "context:" + sourceSet.name + ":" + variant.name + ":" + layer.name
+                    }
                     variant('browser') {
-                        events << "variant:" + name
+                        events << "variant:" + sourceSet.name
                     }
                     layer('main') {
-                        events << "layer:" + name
+                        events << "layer:" + sourceSet.name
                     }
                     unit('browser', 'main') {
-                        events << "unit:" + name
+                        events << "unit:" + sourceSet.name
                     }
                 }
 
@@ -121,15 +125,17 @@ class VariantSourcesPluginFunctionalTest
                         println("browserMain=" + bySourceSet[browserMain.name].collect { it.split(':', 2)[0] }.join(','))
                         println("browserTest=" + bySourceSet[browserTest.name].collect { it.split(':', 2)[0] }.join(','))
                         println("nodeMain=" + bySourceSet[nodeMain.name].collect { it.split(':', 2)[0] }.join(','))
+                        println("context=" + events.find { it.startsWith("context:" + browserMain.name + ":") })
                     }
                 }
                 """);
 
         BuildResult result = runner("help").build();
 
-        assertTrue(result.getOutput().contains("browserMain=variant,layer,unit"));
-        assertTrue(result.getOutput().contains("browserTest=variant"));
-        assertTrue(result.getOutput().contains("nodeMain=layer"));
+        assertTrue(result.getOutput().contains("browserMain=all,variant,layer,unit"));
+        assertTrue(result.getOutput().contains("browserTest=all,variant"));
+        assertTrue(result.getOutput().contains("nodeMain=all,layer"));
+        assertTrue(result.getOutput().contains("context=context:browserMain:browser:main"));
     }
 
     @Test
@@ -153,7 +159,9 @@ class VariantSourcesPluginFunctionalTest
 
                         ctx.sourceSets.getSourceSet(unit).get()
                         variantSources.layer('main') {
-                            declareOutputs('late')
+                            sourceSet {
+                                declareOutputs('late')
+                            }
                         }
                     }
                 }
@@ -187,11 +195,13 @@ class VariantSourcesPluginFunctionalTest
                         def mainLayer = ctx.variants.layers.find { it.name == 'main' }
                         def unit = ctx.compileUnits.requireUnit(browser, mainLayer)
 
-                        def sourceSet = ctx.sourceSets.getSourceSet(unit).get()
+                        def unitSourceSet = ctx.sourceSets.getSourceSet(unit).get()
                         variantSources.layer('main') {
-                            declareOutputs('late')
+                            sourceSet {
+                                declareOutputs('late')
+                            }
                         }
-                        sourceSet.output('late')
+                        unitSourceSet.output('late')
                         println('lateAllowed=ok')
                     }
                 }
@@ -226,11 +236,13 @@ class VariantSourcesPluginFunctionalTest
                         def mainLayer = ctx.variants.layers.find { it.name == 'main' }
                         def unit = ctx.compileUnits.requireUnit(browser, mainLayer)
 
-                        def sourceSet = ctx.sourceSets.getSourceSet(unit).get()
+                        def unitSourceSet = ctx.sourceSets.getSourceSet(unit).get()
                         variantSources.layer('main') {
-                            declareOutputs('late')
+                            sourceSet {
+                                declareOutputs('late')
+                            }
                         }
-                        sourceSet.output('late')
+                        unitSourceSet.output('late')
                         println('lateWarn=ok')
                     }
                 }
@@ -257,7 +269,9 @@ class VariantSourcesPluginFunctionalTest
 
                 variantSources {
                     variant('browser') {
-                        declareOutputs('js')
+                        sourceSet {
+                            declareOutputs('js')
+                        }
                     }
                     lateConfigurationPolicy {
                         allowLateConfiguration()
@@ -351,7 +365,9 @@ class VariantSourcesPluginFunctionalTest
 
                 variantSources {
                     variant('missing') {
-                        declareOutputs('js')
+                        sourceSet {
+                            declareOutputs('js')
+                        }
                     }
                 }
                 """);
@@ -375,7 +391,9 @@ class VariantSourcesPluginFunctionalTest
                 variantSources.whenAvailable { ctx ->
                     def missing = objects.named(org.implab.gradle.variants.core.Variant, 'missing')
                     ctx.configureVariant(missing) {
-                        declareOutputs('js')
+                        sourceSet {
+                            declareOutputs('js')
+                        }
                     }
                 }
                 """);
@@ -398,7 +416,9 @@ class VariantSourcesPluginFunctionalTest
 
                 variantSources {
                     layer('missing') {
-                        declareOutputs('js')
+                        sourceSet {
+                            declareOutputs('js')
+                        }
                     }
                 }
                 """);
@@ -422,7 +442,9 @@ class VariantSourcesPluginFunctionalTest
                 variantSources.whenAvailable { ctx ->
                     def missing = objects.named(org.implab.gradle.variants.core.Layer, 'missing')
                     ctx.configureLayer(missing) {
-                        declareOutputs('js')
+                        sourceSet {
+                            declareOutputs('js')
+                        }
                     }
                 }
                 """);
@@ -446,7 +468,9 @@ class VariantSourcesPluginFunctionalTest
 
                 variantSources {
                     unit('browser', 'test') {
-                        declareOutputs('js')
+                        sourceSet {
+                            declareOutputs('js')
+                        }
                     }
                 }
                 """);
@@ -473,7 +497,9 @@ class VariantSourcesPluginFunctionalTest
                     def testLayer = ctx.variants.layers.find { it.name == 'test' }
                     def unit = new org.implab.gradle.variants.sources.CompileUnit(browser, testLayer)
                     ctx.configureUnit(unit) {
-                        declareOutputs('js')
+                        sourceSet {
+                            declareOutputs('js')
+                        }
                     }
                 }
                 """);