Bug 200380 - [planner] Improve detection of incompatible solutionpost_explanation_work_mergedsa

18 files changed, 532 insertions, 22 deletions

diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/AllExplanation.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/AllExplanation.java
new file mode 100644
index 000000000..54cb11cc8
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/AllExplanation.java
@@ -0,0 +1,22 @@
+package org.eclipse.equinox.p2.tests.planner;
+
+import junit.framework.*;
+
+public class AllExplanation extends TestCase {
+
+	public static Test suite() {
+		TestSuite suite = new TestSuite(AllTests.class.getName());
+		suite.addTestSuite(ExplanationDeepConflict.class);
+		suite.addTestSuite(ExplanationForOptionalDependencies.class);
+		suite.addTestSuite(ExplanationForPartialInstallation.class);
+		suite.addTestSuite(ExplanationSeveralConflictingRoots.class);
+		suite.addTestSuite(MissingDependency.class);
+		suite.addTestSuite(MissingNonGreedyRequirement.class);
+		suite.addTestSuite(MissingNonGreedyRequirement2.class);
+		suite.addTestSuite(MultipleSingleton.class);
+		suite.addTestSuite(PatchTest10.class);
+		suite.addTestSuite(PatchTest12.class);
+		return suite;
+	}
+
+}
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/AllTests.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/AllTests.java
index 8fd39befc..b9286aa20 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/AllTests.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/AllTests.java
@@ -34,6 +34,10 @@ public class AllTests extends TestCase {
 		suite.addTestSuite(Bug262580.class);
 		suite.addTestSuite(DependencyOnSelf.class);
 		suite.addTestSuite(DropinsScenario.class);
+		suite.addTestSuite(ExplanationDeepConflict.class);
+		suite.addTestSuite(ExplanationForOptionalDependencies.class);
+		suite.addTestSuite(ExplanationForPartialInstallation.class);
+		suite.addTestSuite(ExplanationSeveralConflictingRoots.class);
 		suite.addTestSuite(GreedyRequirement.class);
 		suite.addTestSuite(InclusionRuleTest.class);
 		suite.addTestSuite(InclusionRuleTest2.class);
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ExplanationDeepConflict.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ExplanationDeepConflict.java
new file mode 100644
index 000000000..6343536db
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ExplanationDeepConflict.java
@@ -0,0 +1,54 @@
+package org.eclipse.equinox.p2.tests.planner;
+
+import org.eclipse.equinox.internal.provisional.p2.core.Version;
+import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
+import org.eclipse.equinox.internal.provisional.p2.director.*;
+import org.eclipse.equinox.internal.provisional.p2.engine.*;
+import org.eclipse.equinox.internal.provisional.p2.metadata.IInstallableUnit;
+import org.eclipse.equinox.p2.tests.AbstractProvisioningTest;
+
+public class ExplanationDeepConflict extends AbstractProvisioningTest {
+	private IProfile profile;
+	private IPlanner planner;
+	private IEngine engine;
+	private IInstallableUnit sdk;
+
+	@Override
+	protected void setUp() throws Exception {
+		super.setUp();
+		sdk = createIU("SDK", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "SDKPart", new VersionRange("[1.0.0, 1.0.0]"), null));
+		IInstallableUnit sdkPart = createIU("SDKPart", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "InnerSDKPart", new VersionRange("[1.0.0, 1.0.0]"), null));
+		IInstallableUnit innerSdkPart = createIU("InnerSDKPart", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "InnerInnerSDKPart", new VersionRange("[1.0.0, 1.0.0]"), null));
+		IInstallableUnit innerInnerSDKPart = createIU("InnerInnerSDKPart", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), true);
+
+		createTestMetdataRepository(new IInstallableUnit[] {sdk, sdkPart, innerSdkPart, innerInnerSDKPart});
+
+		profile = createProfile("TestProfile." + getName());
+		planner = createPlanner();
+		engine = createEngine();
+
+		ProfileChangeRequest pcr = new ProfileChangeRequest(profile);
+		pcr.addInstallableUnits(new IInstallableUnit[] {sdk});
+		engine.perform(profile, new DefaultPhaseSet(), planner.getProvisioningPlan(pcr, null, null).getOperands(), null, null);
+		assertProfileContains("1.0", profile, new IInstallableUnit[] {sdk, sdkPart, innerSdkPart, innerInnerSDKPart});
+	}
+
+	public void testDeepSingletonConflict() {
+		//CDT will have a singleton conflict with SDK
+		IInstallableUnit cdt = createIU("CDT", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "CDTPart", new VersionRange("[1.0.0, 1.0.0]"), null));
+		IInstallableUnit cdtPart = createIU("CDTPart", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "InnerInnerSDKPart", new VersionRange("[2.0.0, 2.0.0]"), null));
+		IInstallableUnit innerInnerSDKPart2 = createIU("InnerInnerSDKPart", Version.fromOSGiVersion(new org.osgi.framework.Version("2.0.0")), true);
+
+		createTestMetdataRepository(new IInstallableUnit[] {cdt, cdtPart, innerInnerSDKPart2});
+		ProfileChangeRequest pcr = new ProfileChangeRequest(profile);
+		pcr.addInstallableUnits(new IInstallableUnit[] {cdt});
+		ProvisioningPlan plan = planner.getProvisioningPlan(pcr, null, null);
+		System.out.println(plan.getRequestStatus().getExplanations());
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(cdt));
+		//Here we verify that we only return the roots we asked the installation of. The SDK is installable since it is already installed
+		assertFalse(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(sdk));
+		assertTrue(plan.getRequestStatus().getConflictsWithAnyRoots().contains(sdk));
+		//		assertTrue(plan.getRequestStatus(cdt).getConflictsWithAnyRoots().contains(sdk));
+		//		assertTrue(plan.getRequestStatus(cdt).getConflictsWithInstalledRoots().contains(sdk));
+	}
+}
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ExplanationForOptionalDependencies.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ExplanationForOptionalDependencies.java
new file mode 100644
index 000000000..fa589e4de
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ExplanationForOptionalDependencies.java
@@ -0,0 +1,57 @@
+package org.eclipse.equinox.p2.tests.planner;
+
+import org.eclipse.equinox.internal.provisional.p2.core.Version;
+import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
+import org.eclipse.equinox.internal.provisional.p2.director.*;
+import org.eclipse.equinox.internal.provisional.p2.engine.*;
+import org.eclipse.equinox.internal.provisional.p2.metadata.*;
+import org.eclipse.equinox.p2.tests.AbstractProvisioningTest;
+
+public class ExplanationForOptionalDependencies extends AbstractProvisioningTest {
+	private IProfile profile;
+	private IPlanner planner;
+	private IEngine engine;
+	private IInstallableUnit sdk;
+
+	@Override
+	protected void setUp() throws Exception {
+		super.setUp();
+		sdk = createIU("SDK", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "SDKPart", new VersionRange("[1.0.0, 1.0.0]"), null));
+		IInstallableUnit sdkPart = createIU("SDKPart", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), true);
+		IInstallableUnit sdkPart2 = createIU("SDKPart", Version.fromOSGiVersion(new org.osgi.framework.Version("2.0.0")), true);
+
+		createTestMetdataRepository(new IInstallableUnit[] {sdk, sdkPart, sdkPart2});
+
+		profile = createProfile("TestProfile." + getName());
+		planner = createPlanner();
+		engine = createEngine();
+
+		ProfileChangeRequest pcr = new ProfileChangeRequest(profile);
+		pcr.addInstallableUnits(new IInstallableUnit[] {sdk});
+		engine.perform(profile, new DefaultPhaseSet(), planner.getProvisioningPlan(pcr, null, null).getOperands(), null, null);
+
+	}
+
+	public void testNoProblemWithMissingOptionalDependency() {
+		//CDT will be missing a requirement but it is optional so everything should be good
+		//EMF will be not be good because it is missing a requirement
+		IRequiredCapability missingOptionalDependency = MetadataFactory.createRequiredCapability(IInstallableUnit.NAMESPACE_IU_ID, "MissingSomething", new VersionRange("[1.0.0, 1.0.0]"), null, true, false);
+		IInstallableUnit cdt = createIU("CDT", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), new IRequiredCapability[] {missingOptionalDependency});
+
+		IRequiredCapability emfMissing = MetadataFactory.createRequiredCapability(IInstallableUnit.NAMESPACE_IU_ID, "EMFPart", new VersionRange("[1.0.0, 1.0.0]"), null, false, false);
+		IInstallableUnit emf = createIU("EMF", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), new IRequiredCapability[] {emfMissing}, NO_PROPERTIES, true);
+
+		createTestMetdataRepository(new IInstallableUnit[] {cdt, emf});
+		ProfileChangeRequest pcr = new ProfileChangeRequest(profile);
+		pcr.addInstallableUnits(new IInstallableUnit[] {cdt, emf});
+		ProvisioningPlan plan = planner.getProvisioningPlan(pcr, null, null);
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(emf));
+		assertFalse(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(cdt));
+		assertFalse(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(sdk));
+
+		//		assertTrue(plan.getRequestStatus(cdt).getSeverity() != IStatus.ERROR);
+		//
+		//		assertTrue(plan.getRequestStatus(emf).getSeverity() == IStatus.ERROR);
+		//		assertEquals(0, plan.getRequestStatus(emf).getConflictsWithInstalledRoots());
+	}
+}
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ExplanationForPartialInstallation.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ExplanationForPartialInstallation.java
new file mode 100644
index 000000000..a54d81942
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ExplanationForPartialInstallation.java
@@ -0,0 +1,86 @@
+package org.eclipse.equinox.p2.tests.planner;
+
+import org.eclipse.equinox.internal.provisional.p2.core.Version;
+import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
+import org.eclipse.equinox.internal.provisional.p2.director.*;
+import org.eclipse.equinox.internal.provisional.p2.engine.*;
+import org.eclipse.equinox.internal.provisional.p2.metadata.IInstallableUnit;
+import org.eclipse.equinox.p2.tests.AbstractProvisioningTest;
+
+public class ExplanationForPartialInstallation extends AbstractProvisioningTest {
+	private IProfile profile;
+	private IPlanner planner;
+	private IEngine engine;
+	private IInstallableUnit sdk;
+
+	@Override
+	protected void setUp() throws Exception {
+		super.setUp();
+		sdk = createIU("SDK", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "SDKPart", new VersionRange("[1.0.0, 1.0.0]"), null));
+		IInstallableUnit sdkPart = createIU("SDKPart", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), true);
+		IInstallableUnit sdkPart2 = createIU("SDKPart", Version.fromOSGiVersion(new org.osgi.framework.Version("2.0.0")), true);
+
+		createTestMetdataRepository(new IInstallableUnit[] {sdk, sdkPart, sdkPart2});
+
+		profile = createProfile("TestProfile." + getName());
+		planner = createPlanner();
+		engine = createEngine();
+
+		ProfileChangeRequest pcr = new ProfileChangeRequest(profile);
+		pcr.addInstallableUnits(new IInstallableUnit[] {sdk});
+		engine.perform(profile, new DefaultPhaseSet(), planner.getProvisioningPlan(pcr, null, null).getOperands(), null, null);
+
+	}
+
+	public void testPartialProblemSingleton() {
+		//CDT will have a singleton conflict with SDK
+		//EMF will be good
+		IInstallableUnit cdt = createIU("CDT", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "SDKPart", new VersionRange("[2.0.0, 2.0.0]"), null));
+
+		IInstallableUnit emf = createIU("EMF", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), true);
+
+		createTestMetdataRepository(new IInstallableUnit[] {cdt, emf});
+		ProfileChangeRequest pcr = new ProfileChangeRequest(profile);
+		pcr.addInstallableUnits(new IInstallableUnit[] {cdt, emf});
+		ProvisioningPlan plan = planner.getProvisioningPlan(pcr, null, null);
+		System.out.println(plan.getRequestStatus().getExplanations());
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(cdt));
+		assertFalse(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(emf));
+		assertFalse(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(sdk));
+
+		//		assertTrue(plan.getRequestStatus(cdt).getSeverity() == IStatus.ERROR);
+		//		assertTrue(plan.getRequestStatus(cdt).getConflictsWithAnyRoots().contains(sdk));
+		//		assertTrue(plan.getRequestStatus(cdt).getConflictsWithInstalledRoots().contains(sdk));
+		//
+		//		assertTrue(plan.getRequestStatus(emf).getSeverity() != IStatus.ERROR);
+		//		assertEquals(0, plan.getRequestStatus(emf).getConflictsWithAnyRoots().size());
+		//		assertEquals(0, plan.getRequestStatus(emf).getConflictsWithInstalledRoots().size());
+		//
+		//		assertNull(plan.getRequestStatus(sdk));
+	}
+
+	public void testPartialProblemRequirement() {
+		//CDT will be missing a requirement
+		//EMF will be good
+		IInstallableUnit cdt = createIU("CDT", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "MissingPart", new VersionRange("[2.0.0, 2.0.0]"), null));
+
+		IInstallableUnit emf = createIU("EMF", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), true);
+
+		createTestMetdataRepository(new IInstallableUnit[] {cdt, emf});
+		ProfileChangeRequest pcr = new ProfileChangeRequest(profile);
+		pcr.addInstallableUnits(new IInstallableUnit[] {cdt, emf});
+		ProvisioningPlan plan = planner.getProvisioningPlan(pcr, null, null);
+		System.out.println(plan.getRequestStatus().getExplanations());
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(cdt));
+		assertFalse(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(emf));
+		assertFalse(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(sdk));
+
+		//		assertTrue(plan.getRequestStatus(cdt).getSeverity() == IStatus.ERROR);
+		//		assertEquals(0, plan.getRequestStatus(cdt).getConflictsWithAnyRoots().size());
+		//		assertEquals(0, plan.getRequestStatus(cdt).getConflictsWithInstalledRoots().size());
+		//
+		//		assertTrue(plan.getRequestStatus(emf).getSeverity() != IStatus.ERROR);
+		//		assertEquals(0, plan.getRequestStatus(emf).getConflictsWithAnyRoots().size());
+		//		assertEquals(0, plan.getRequestStatus(emf).getConflictsWithInstalledRoots().size());
+	}
+}
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ExplanationSeveralConflictingRoots.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ExplanationSeveralConflictingRoots.java
new file mode 100644
index 000000000..28c05d0d2
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ExplanationSeveralConflictingRoots.java
@@ -0,0 +1,104 @@
+package org.eclipse.equinox.p2.tests.planner;
+
+import org.eclipse.equinox.internal.provisional.p2.core.Version;
+import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
+import org.eclipse.equinox.internal.provisional.p2.director.*;
+import org.eclipse.equinox.internal.provisional.p2.engine.*;
+import org.eclipse.equinox.internal.provisional.p2.metadata.*;
+import org.eclipse.equinox.p2.tests.AbstractProvisioningTest;
+
+public class ExplanationSeveralConflictingRoots extends AbstractProvisioningTest {
+	private IProfile profile;
+	private IPlanner planner;
+	private IInstallableUnit sdk;
+
+	@Override
+	protected void setUp() throws Exception {
+		super.setUp();
+		sdk = createIU("SDK", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "SDKPart", new VersionRange("[1.0.0, 1.0.0]"), null));
+		IInstallableUnit sdkPart = createIU("SDKPart", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), true);
+		IInstallableUnit sdkPart2 = createIU("SDKPart", Version.fromOSGiVersion(new org.osgi.framework.Version("2.0.0")), true);
+
+		createTestMetdataRepository(new IInstallableUnit[] {sdk, sdkPart, sdkPart2});
+
+		profile = createProfile("TestProfile." + getName());
+		planner = createPlanner();
+		IEngine engine = createEngine();
+
+		ProfileChangeRequest pcr = new ProfileChangeRequest(profile);
+		pcr.addInstallableUnits(new IInstallableUnit[] {sdk});
+		engine.perform(profile, new DefaultPhaseSet(), planner.getProvisioningPlan(pcr, null, null).getOperands(), null, null);
+
+	}
+
+	public void testConflictingSingletonAndMissingDependency() {
+		//CDT will have a singleton conflict with SDK
+		//EMF will be missing a dependency
+		IInstallableUnit cdt = createIU("CDT", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "SDKPart", new VersionRange("[2.0.0, 2.0.0]"), null));
+
+		IInstallableUnit emf = createIU("EMF", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "EMFPart", new VersionRange("[1.0.0, 1.0.0]"), null));
+
+		createTestMetdataRepository(new IInstallableUnit[] {cdt, emf});
+		ProfileChangeRequest pcr = new ProfileChangeRequest(profile);
+		pcr.addInstallableUnits(new IInstallableUnit[] {cdt, emf});
+		ProvisioningPlan plan = planner.getProvisioningPlan(pcr, null, null);
+		System.out.println(plan.getRequestStatus().getExplanations());
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(cdt));
+		//		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(emf));
+
+		//		assertTrue(plan.getRequestStatus(cdt).getConflictsWithInstalledRoots().contains(sdk));
+		//		assertTrue(plan.getRequestStatus(cdt).getConflictsWithAnyRoots().contains(sdk));
+		//		assertEquals(0, plan.getRequestStatus(emf).getConflictsWithAnyRoots().size());
+		//		assertEquals(0, plan.getRequestStatus(emf).getConflictsWithInstalledRoots().size());
+	}
+
+	public void testConflictingSingletonAndMissingDependency2() {
+		//CDT will have a singleton conflict EMF
+		//EMF will be missing a dependency and will be in conflict with CDT
+		IInstallableUnit cdt = createIU("CDT", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "ASingleton", new VersionRange("[2.0.0, 2.0.0]"), null));
+		IInstallableUnit aSingleton1 = createIU("ASingleton", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), true);
+		IInstallableUnit aSingleton2 = createIU("ASingleton", Version.fromOSGiVersion(new org.osgi.framework.Version("2.0.0")), true);
+
+		IRequiredCapability emfOnSingleton = MetadataFactory.createRequiredCapability(IInstallableUnit.NAMESPACE_IU_ID, "ASingleton", new VersionRange("[1.0.0, 1.0.0]"), null, false, false);
+		IRequiredCapability emfMissing = MetadataFactory.createRequiredCapability(IInstallableUnit.NAMESPACE_IU_ID, "EMFPart", new VersionRange("[1.0.0, 1.0.0]"), null, false, false);
+		IInstallableUnit emf = createIU("EMF", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), new IRequiredCapability[] {emfOnSingleton, emfMissing});
+
+		createTestMetdataRepository(new IInstallableUnit[] {aSingleton1, aSingleton2, cdt, emf});
+		ProfileChangeRequest pcr = new ProfileChangeRequest(profile);
+		pcr.addInstallableUnits(new IInstallableUnit[] {cdt, emf});
+		ProvisioningPlan plan = planner.getProvisioningPlan(pcr, null, null);
+		System.out.println(plan.getRequestStatus().getExplanations());
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(cdt));
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(emf));
+
+		//		assertEquals(0, plan.getRequestStatus(cdt).getConflictsWithInstalledRoots().size());
+		//		assertTrue(plan.getRequestStatus(cdt).getConflictsWithAnyRoots().contains(emf));
+		//		assertEquals(0, plan.getRequestStatus(emf).getConflictsWithInstalledRoots().size());
+		//		assertTrue(plan.getRequestStatus(emf).getConflictsWithAnyRoots().contains(cdt));
+	}
+
+	public void testConflictingSingletonAndMissingDependency3() {
+		//CDT will have a singleton conflict EMF and with the SDK
+		//EMF will be conflicting with CDT
+		IInstallableUnit cdt = createIU("CDT", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), createRequiredCapabilities(IInstallableUnit.NAMESPACE_IU_ID, "SDKPart", new VersionRange("[2.0.0, 2.0.0]"), null));
+		IInstallableUnit sdkPart3 = createIU("SDKPart", Version.fromOSGiVersion(new org.osgi.framework.Version("3.0.0")), true);
+
+		IRequiredCapability emfOnSingleton = MetadataFactory.createRequiredCapability(IInstallableUnit.NAMESPACE_IU_ID, "SDKPart", new VersionRange("[1.0.0, 1.0.0]"), null, false, false);
+		IRequiredCapability emfMissing = MetadataFactory.createRequiredCapability(IInstallableUnit.NAMESPACE_IU_ID, "EMFPart", new VersionRange("[1.0.0, 1.0.0]"), null, false, false);
+		IInstallableUnit emf = createIU("EMF", Version.fromOSGiVersion(new org.osgi.framework.Version("1.0.0")), new IRequiredCapability[] {emfOnSingleton, emfMissing});
+
+		createTestMetdataRepository(new IInstallableUnit[] {sdkPart3, cdt, emf});
+		ProfileChangeRequest pcr = new ProfileChangeRequest(profile);
+		pcr.addInstallableUnits(new IInstallableUnit[] {cdt, emf});
+		ProvisioningPlan plan = planner.getProvisioningPlan(pcr, null, null);
+		System.out.println(plan.getRequestStatus().getExplanations());
+		//		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(cdt));
+		//		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(emf));
+
+		//		assertTrue(plan.getRequestStatus(cdt).getConflictsWithInstalledRoots().contains(sdk));
+		//		assertTrue(plan.getRequestStatus(cdt).getConflictsWithAnyRoots().contains(sdk));
+		//		assertTrue(plan.getRequestStatus(cdt).getConflictsWithAnyRoots().contains(emf));
+		//		assertEquals(0, plan.getRequestStatus(emf).getConflictsWithInstalledRoots().size());
+		//		assertTrue(plan.getRequestStatus(emf).getConflictsWithAnyRoots().contains(cdt));
+	}
+}
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MissingDependency.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MissingDependency.java
index abcadad76..7e97ec8bf 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MissingDependency.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MissingDependency.java
@@ -8,7 +8,9 @@
  ******************************************************************************/
 package org.eclipse.equinox.p2.tests.planner;
 
+import java.util.Set;
 import org.eclipse.core.runtime.IStatus;
+import org.eclipse.equinox.internal.p2.director.Explanation;
 import org.eclipse.equinox.internal.provisional.p2.core.Version;
 import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
 import org.eclipse.equinox.internal.provisional.p2.director.*;
@@ -43,4 +45,20 @@ public class MissingDependency extends AbstractProvisioningTest {
 		ProvisioningPlan plan = planner.getProvisioningPlan(req, null, null);
 		assertEquals(IStatus.ERROR, plan.getStatus().getSeverity());
 	}
+
+	public void testExplanation() {
+		ProfileChangeRequest req = new ProfileChangeRequest(profile);
+		req.addInstallableUnits(new IInstallableUnit[] {a1, b1});
+		ProvisioningPlan plan = planner.getProvisioningPlan(req, null, null);
+		assertEquals(IStatus.ERROR, plan.getStatus().getSeverity());
+		Set explanation = plan.getRequestStatus().getExplanations();
+		System.out.println(explanation);
+		assertEquals(2, explanation.size());
+		Set rootConflictingIUs = plan.getRequestStatus().getConflictsWithInstalledRoots();
+		System.out.println(rootConflictingIUs);
+		assertEquals(1, rootConflictingIUs.size());
+		assertTrue(rootConflictingIUs.contains(b1));
+		assertFalse(rootConflictingIUs.contains(a1));
+		assertEquals(Explanation.MISSING_REQUIREMENT, plan.getRequestStatus().getShortExplanation());
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MissingNonGreedyRequirement.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MissingNonGreedyRequirement.java
index f1513ab74..3da66a88d 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MissingNonGreedyRequirement.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MissingNonGreedyRequirement.java
@@ -8,7 +8,9 @@
  ******************************************************************************/
 package org.eclipse.equinox.p2.tests.planner;
 
+import java.util.Set;
 import org.eclipse.core.runtime.IStatus;
+import org.eclipse.equinox.internal.p2.director.Explanation;
 import org.eclipse.equinox.internal.provisional.p2.core.Version;
 import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
 import org.eclipse.equinox.internal.provisional.p2.director.*;
@@ -47,4 +49,15 @@ public class MissingNonGreedyRequirement extends AbstractProvisioningTest {
 		ProvisioningPlan plan = planner.getProvisioningPlan(req, null, null);
 		assertEquals(IStatus.ERROR, plan.getStatus().getSeverity());
 	}
+
+	public void testExplanation() {
+		ProfileChangeRequest req = new ProfileChangeRequest(profile);
+		req.addInstallableUnits(new IInstallableUnit[] {a1});
+		ProvisioningPlan plan = planner.getProvisioningPlan(req, null, null);
+		assertEquals(IStatus.ERROR, plan.getStatus().getSeverity());
+		Set explanation = plan.getRequestStatus().getExplanations();
+		assertFalse(explanation.isEmpty());
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(a1));
+		assertEquals(Explanation.MISSING_REQUIREMENT, plan.getRequestStatus().getShortExplanation());
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MissingNonGreedyRequirement2.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MissingNonGreedyRequirement2.java
index c0a32ea92..4c427097f 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MissingNonGreedyRequirement2.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MissingNonGreedyRequirement2.java
@@ -8,7 +8,9 @@
  ******************************************************************************/
 package org.eclipse.equinox.p2.tests.planner;
 
+import java.util.Set;
 import org.eclipse.core.runtime.IStatus;
+import org.eclipse.equinox.internal.p2.director.Explanation;
 import org.eclipse.equinox.internal.provisional.p2.core.Version;
 import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
 import org.eclipse.equinox.internal.provisional.p2.director.*;
@@ -44,4 +46,16 @@ public class MissingNonGreedyRequirement2 extends AbstractProvisioningTest {
 		ProvisioningPlan plan = planner.getProvisioningPlan(req, null, null);
 		assertEquals(IStatus.ERROR, plan.getStatus().getSeverity());
 	}
+
+	public void testExplanation() {
+		ProfileChangeRequest req = new ProfileChangeRequest(profile);
+		req.addInstallableUnits(new IInstallableUnit[] {a1});
+		ProvisioningPlan plan = planner.getProvisioningPlan(req, null, null);
+		assertEquals(IStatus.ERROR, plan.getStatus().getSeverity());
+		Set explanation = plan.getRequestStatus().getExplanations();
+		assertFalse(explanation.isEmpty());
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(a1));
+		assertEquals(Explanation.MISSING_REQUIREMENT, plan.getRequestStatus().getShortExplanation());
+
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MultipleSingleton.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MultipleSingleton.java
index d8c229bff..6c7ee0b6c 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MultipleSingleton.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/MultipleSingleton.java
@@ -8,11 +8,12 @@
  ******************************************************************************/
 package org.eclipse.equinox.p2.tests.planner;
 
+import java.util.Set;
 import org.eclipse.core.runtime.IStatus;
+import org.eclipse.equinox.internal.p2.director.Explanation;
 import org.eclipse.equinox.internal.provisional.p2.core.Version;
 import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
-import org.eclipse.equinox.internal.provisional.p2.director.IPlanner;
-import org.eclipse.equinox.internal.provisional.p2.director.ProfileChangeRequest;
+import org.eclipse.equinox.internal.provisional.p2.director.*;
 import org.eclipse.equinox.internal.provisional.p2.engine.IProfile;
 import org.eclipse.equinox.internal.provisional.p2.metadata.*;
 import org.eclipse.equinox.p2.tests.AbstractProvisioningTest;
@@ -75,6 +76,20 @@ public class MultipleSingleton extends AbstractProvisioningTest {
 		assertEquals(IStatus.ERROR, planner.getProvisioningPlan(req, null, null).getStatus().getSeverity());
 	}
 
+	public void testExplanation2() {
+		ProfileChangeRequest req = new ProfileChangeRequest(profile);
+		req.addInstallableUnits(new IInstallableUnit[] {y});
+		ProvisioningPlan plan = planner.getProvisioningPlan(req, null, null);
+		assertEquals(IStatus.ERROR, plan.getStatus().getSeverity());
+		Set explanation = plan.getRequestStatus().getExplanations();
+		System.out.println(explanation);
+		assertFalse(explanation.isEmpty());
+		assertEquals(Explanation.VIOLATED_SINGLETON_CONSTRAINT, plan.getRequestStatus().getShortExplanation());
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(y));
+		assertEquals(1, plan.getRequestStatus().getConflictsWithInstalledRoots().size());
+
+	}
+
 	public void test3() {
 		//Test that we can install A3 and A4 together
 		ProfileChangeRequest req = new ProfileChangeRequest(profile);
@@ -89,6 +104,19 @@ public class MultipleSingleton extends AbstractProvisioningTest {
 		assertEquals(IStatus.ERROR, planner.getProvisioningPlan(req, null, null).getStatus().getSeverity());
 	}
 
+	public void testExplanation4() {
+		ProfileChangeRequest req = new ProfileChangeRequest(profile);
+		req.addInstallableUnits(new IInstallableUnit[] {w});
+		ProvisioningPlan plan = planner.getProvisioningPlan(req, null, null);
+		assertEquals(IStatus.ERROR, plan.getStatus().getSeverity());
+		Set explanation = plan.getRequestStatus().getExplanations();
+		System.out.println(explanation);
+		assertFalse(explanation.isEmpty());
+		assertEquals(Explanation.VIOLATED_SINGLETON_CONSTRAINT, plan.getRequestStatus().getShortExplanation());
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(w));
+
+	}
+
 	public void test5b() {
 		//Validate the setup
 		ProfileChangeRequest req = new ProfileChangeRequest(profile);
@@ -109,4 +137,18 @@ public class MultipleSingleton extends AbstractProvisioningTest {
 		req.addInstallableUnits(new IInstallableUnit[] {u, v});
 		assertEquals(IStatus.ERROR, planner.getProvisioningPlan(req, null, null).getStatus().getSeverity());
 	}
+
+	public void testExplanation5() {
+		ProfileChangeRequest req = new ProfileChangeRequest(profile);
+		req.addInstallableUnits(new IInstallableUnit[] {u, v});
+		ProvisioningPlan plan = planner.getProvisioningPlan(req, null, null);
+		assertEquals(IStatus.ERROR, plan.getStatus().getSeverity());
+		Set explanation = plan.getRequestStatus().getExplanations();
+		assertFalse(explanation.isEmpty());
+		assertEquals(Explanation.VIOLATED_SINGLETON_CONSTRAINT, plan.getRequestStatus().getShortExplanation());
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(u));
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(v));
+		System.out.println(explanation);
+
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest10.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest10.java
index 9fcfa7dd8..cc749818a 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest10.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest10.java
@@ -8,8 +8,7 @@
  ******************************************************************************/
 package org.eclipse.equinox.p2.tests.planner;
 
-import org.eclipse.equinox.internal.provisional.p2.metadata.MetadataFactory;
-
+import java.util.Set;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.equinox.internal.provisional.p2.core.Version;
 import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
@@ -75,4 +74,18 @@ public class PatchTest10 extends AbstractProvisioningTest {
 		ProvisioningPlan plan3 = planner.getProvisioningPlan(req3, null, null);
 		assertEquals(IStatus.ERROR, plan3.getStatus().getSeverity());
 	}
+
+	public void testExplanation() {
+		ProfileChangeRequest req3 = new ProfileChangeRequest(profile1);
+		req3.addInstallableUnits(new IInstallableUnit[] {a1, p1, pp1});
+		ProvisioningPlan plan3 = planner.getProvisioningPlan(req3, null, null);
+		assertEquals(IStatus.ERROR, plan3.getStatus().getSeverity());
+		Set problems = plan3.getRequestStatus().getConflictsWithInstalledRoots();
+		System.out.println(problems);
+		System.out.println(plan3.getRequestStatus().getExplanations());
+		assertEquals(3, problems.size());
+		assertTrue(problems.contains(a1));
+		assertTrue(problems.contains(p1));
+		assertTrue(problems.contains(pp1));
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest12.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest12.java
index 88b4e2c49..4d1f603f4 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest12.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest12.java
@@ -8,9 +8,9 @@
  ******************************************************************************/
 package org.eclipse.equinox.p2.tests.planner;
 
-import org.eclipse.equinox.internal.provisional.p2.metadata.MetadataFactory;
-
+import java.util.Set;
 import org.eclipse.core.runtime.IStatus;
+import org.eclipse.equinox.internal.p2.director.Explanation;
 import org.eclipse.equinox.internal.provisional.p2.core.Version;
 import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
 import org.eclipse.equinox.internal.provisional.p2.director.*;
@@ -66,4 +66,14 @@ public class PatchTest12 extends AbstractProvisioningTest {
 		assertTrue(IStatus.ERROR == plan3.getStatus().getSeverity());
 
 	}
+
+	public void testExplanation1() {
+		ProfileChangeRequest req3 = new ProfileChangeRequest(profile1);
+		req3.addInstallableUnits(new IInstallableUnit[] {a1, p1});
+		ProvisioningPlan plan3 = planner.getProvisioningPlan(req3, null, null);
+		assertTrue(IStatus.ERROR == plan3.getStatus().getSeverity());
+		Set conflictRootIUs = plan3.getRequestStatus().getConflictsWithInstalledRoots();
+		assertTrue(conflictRootIUs.contains(p1));
+		assertEquals(Explanation.MISSING_REQUIREMENT, plan3.getRequestStatus().getShortExplanation());
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest2.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest2.java
index 7d81a4b25..60c396ea9 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest2.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest2.java
@@ -8,9 +8,9 @@
  ******************************************************************************/
 package org.eclipse.equinox.p2.tests.planner;
 
-import org.eclipse.equinox.internal.provisional.p2.metadata.MetadataFactory;
-
+import java.util.Set;
 import org.eclipse.core.runtime.IStatus;
+import org.eclipse.equinox.internal.p2.director.Explanation;
 import org.eclipse.equinox.internal.provisional.p2.core.Version;
 import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
 import org.eclipse.equinox.internal.provisional.p2.director.*;
@@ -90,4 +90,30 @@ public class PatchTest2 extends AbstractProvisioningTest {
 		assertEquals(IStatus.ERROR, plan5.getStatus().getSeverity());
 
 	}
+
+	public void testExplanation3() {
+		//p2 does not cause a1 to resolve therefore the application fails
+		ProfileChangeRequest req3 = new ProfileChangeRequest(profile1);
+		req3.addInstallableUnits(new IInstallableUnit[] {a1, p2});
+		ProvisioningPlan plan3 = planner.getProvisioningPlan(req3, null, null);
+		assertEquals(IStatus.ERROR, plan3.getStatus().getSeverity());
+		assertEquals(Explanation.MISSING_REQUIREMENT, plan3.getRequestStatus().getShortExplanation());
+		System.out.println(plan3.getRequestStatus().getExplanations());
+		Set conflictingRoot = plan3.getRequestStatus().getConflictsWithInstalledRoots();
+		assertTrue(conflictingRoot.contains(a1));
+		assertEquals(1, conflictingRoot.size());
+	}
+
+	public void testExplanation5() {
+		//p4 does not cause a1 to resolve therefore the application fails
+		ProfileChangeRequest req5 = new ProfileChangeRequest(profile1);
+		req5.addInstallableUnits(new IInstallableUnit[] {a1, p4});
+		ProvisioningPlan plan5 = planner.getProvisioningPlan(req5, null, null);
+		assertEquals(IStatus.ERROR, plan5.getStatus().getSeverity());
+		assertEquals(Explanation.MISSING_REQUIREMENT, plan5.getRequestStatus().getShortExplanation());
+		System.out.println(plan5.getRequestStatus().getExplanations());
+		Set conflictingRoot = plan5.getRequestStatus().getConflictsWithInstalledRoots();
+		assertTrue(conflictingRoot.contains(a1));
+		assertEquals(1, conflictingRoot.size());
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest6.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest6.java
index cb5831b9d..e57222542 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest6.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest6.java
@@ -8,9 +8,9 @@
  ******************************************************************************/
 package org.eclipse.equinox.p2.tests.planner;
 
-import org.eclipse.equinox.internal.provisional.p2.metadata.MetadataFactory;
-
+import java.util.Set;
 import org.eclipse.core.runtime.IStatus;
+import org.eclipse.equinox.internal.p2.director.Explanation;
 import org.eclipse.equinox.internal.provisional.p2.core.Version;
 import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
 import org.eclipse.equinox.internal.provisional.p2.director.*;
@@ -96,4 +96,16 @@ public class PatchTest6 extends AbstractProvisioningTest {
 		assertInstallOperand(plan5, d1);
 		assertInstallOperand(plan5, c1);
 	}
+
+	public void testExplanation1() {
+		//Confirm that a1 and c1 can't be installed
+		ProfileChangeRequest req1 = new ProfileChangeRequest(profile1);
+		req1.addInstallableUnits(new IInstallableUnit[] {a1, c1});
+		ProvisioningPlan plan1 = planner.getProvisioningPlan(req1, null, null);
+		assertEquals(IStatus.ERROR, plan1.getStatus().getSeverity());
+		assertEquals(Explanation.MISSING_REQUIREMENT, plan1.getRequestStatus().getShortExplanation());
+		Set conflictingRoots = plan1.getRequestStatus().getConflictsWithInstalledRoots();
+		assertEquals(1, conflictingRoots.size());
+		assertTrue(conflictingRoots.contains(a1) || conflictingRoots.contains(c1));
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest9.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest9.java
index 47b4a43e3..ae45ae2b6 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest9.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTest9.java
@@ -8,9 +8,9 @@
  ******************************************************************************/
 package org.eclipse.equinox.p2.tests.planner;
 
-import org.eclipse.equinox.internal.provisional.p2.metadata.MetadataFactory;
-
+import java.util.Set;
 import org.eclipse.core.runtime.IStatus;
+import org.eclipse.equinox.internal.p2.director.Explanation;
 import org.eclipse.equinox.internal.provisional.p2.core.Version;
 import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
 import org.eclipse.equinox.internal.provisional.p2.director.*;
@@ -59,6 +59,18 @@ public class PatchTest9 extends AbstractProvisioningTest {
 		assertEquals(IStatus.ERROR, plan1.getStatus().getSeverity());
 	}
 
+	public void testExplanation() {
+		//The application of the patch does not succeed because there is no C matching the requirement imposed by the patch
+		ProfileChangeRequest req1 = new ProfileChangeRequest(profile1);
+		req1.addInstallableUnits(new IInstallableUnit[] {a1, p1});
+		ProvisioningPlan plan1 = planner.getProvisioningPlan(req1, null, null);
+		assertEquals(IStatus.ERROR, plan1.getStatus().getSeverity());
+		assertEquals(Explanation.MISSING_REQUIREMENT, plan1.getRequestStatus().getShortExplanation());
+		Set conflictingRoots = plan1.getRequestStatus().getConflictsWithInstalledRoots();
+		assertEquals(1, conflictingRoots.size());
+		assertTrue(conflictingRoots.contains(p1));
+	}
+
 	public void testPatchApply() {
 		//The application of the patch succeed because the dependency that PP puts on C is optional
 		ProfileChangeRequest req2 = new ProfileChangeRequest(profile1);
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTestUpdate.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTestUpdate.java
index f099c2c6f..f570ed7a4 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTestUpdate.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/PatchTestUpdate.java
@@ -8,9 +8,9 @@
  ******************************************************************************/
 package org.eclipse.equinox.p2.tests.planner;
 
-import org.eclipse.equinox.internal.provisional.p2.metadata.MetadataFactory;
-
+import java.util.Set;
 import org.eclipse.core.runtime.IStatus;
+import org.eclipse.equinox.internal.p2.director.Explanation;
 import org.eclipse.equinox.internal.provisional.p2.core.Version;
 import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
 import org.eclipse.equinox.internal.provisional.p2.director.*;
@@ -77,4 +77,18 @@ public class PatchTestUpdate extends AbstractProvisioningTest {
 		ProvisioningPlan plan = planner.getProvisioningPlan(req1, null, null);
 		assertEquals(IStatus.ERROR, plan.getStatus().getSeverity());
 	}
+
+	public void testExplanation() {
+		//The update of the feature is expected to fail because the patches are installed without flexibility (strict mode) 
+		ProfileChangeRequest req1 = new ProfileChangeRequest(profile1);
+		req1.addInstallableUnits(new IInstallableUnit[] {p2Feature20});
+		req1.setInstallableUnitInclusionRules(p2Feature20, PlannerHelper.createStrictInclusionRule(p2Feature20));
+		req1.removeInstallableUnits(new IInstallableUnit[] {p2Feature});
+		ProvisioningPlan plan = planner.getProvisioningPlan(req1, null, null);
+		assertEquals(IStatus.ERROR, plan.getStatus().getSeverity());
+		Set conflictingRoot = plan.getRequestStatus().getConflictsWithInstalledRoots();
+		assertEquals(1, conflictingRoot.size());
+		assertTrue(conflictingRoot.contains(p2Feature20));
+		assertEquals(Explanation.VIOLATED_SINGLETON_CONSTRAINT, plan.getRequestStatus().getShortExplanation());
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ProvisioningPlanQueryTest.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ProvisioningPlanQueryTest.java
index b06c477c5..025703c57 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ProvisioningPlanQueryTest.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/ProvisioningPlanQueryTest.java
@@ -17,22 +17,22 @@ public class ProvisioningPlanQueryTest extends AbstractProvisioningTest {
 
 	public void testAddition() {
 		Operand[] ops = new Operand[] {new InstallableUnitOperand(null, createIU("A"))};
-		Collector c = new ProvisioningPlan(Status.OK_STATUS, ops, null).getAdditions().query(InstallableUnitQuery.ANY, new Collector(), new NullProgressMonitor());
+		Collector c = new ProvisioningPlan(Status.OK_STATUS, ops, null, null).getAdditions().query(InstallableUnitQuery.ANY, new Collector(), new NullProgressMonitor());
 		assertEquals(1, c.size());
-		assertEquals(0, new ProvisioningPlan(Status.OK_STATUS, ops, null).getRemovals().query(InstallableUnitQuery.ANY, new Collector(), new NullProgressMonitor()).size());
+		assertEquals(0, new ProvisioningPlan(Status.OK_STATUS, ops, null, null).getRemovals().query(InstallableUnitQuery.ANY, new Collector(), new NullProgressMonitor()).size());
 	}
 
 	public void testRemoval() {
 		Operand[] ops = new Operand[] {new InstallableUnitOperand(createIU("A"), null)};
-		Collector c = new ProvisioningPlan(Status.OK_STATUS, ops, null).getRemovals().query(InstallableUnitQuery.ANY, new Collector(), new NullProgressMonitor());
+		Collector c = new ProvisioningPlan(Status.OK_STATUS, ops, null, null).getRemovals().query(InstallableUnitQuery.ANY, new Collector(), new NullProgressMonitor());
 		assertEquals(1, c.size());
-		assertEquals(0, new ProvisioningPlan(Status.OK_STATUS, ops, null).getAdditions().query(InstallableUnitQuery.ANY, new Collector(), new NullProgressMonitor()).size());
+		assertEquals(0, new ProvisioningPlan(Status.OK_STATUS, ops, null, null).getAdditions().query(InstallableUnitQuery.ANY, new Collector(), new NullProgressMonitor()).size());
 	}
 
 	public void testUpdate() {
 		Operand[] ops = new Operand[] {new InstallableUnitOperand(createIU("A"), createIU("B"))};
-		Collector c = new ProvisioningPlan(Status.OK_STATUS, ops, null).getRemovals().query(InstallableUnitQuery.ANY, new Collector(), new NullProgressMonitor());
+		Collector c = new ProvisioningPlan(Status.OK_STATUS, ops, null, null).getRemovals().query(InstallableUnitQuery.ANY, new Collector(), new NullProgressMonitor());
 		assertEquals(1, c.size());
-		assertEquals(1, new ProvisioningPlan(Status.OK_STATUS, ops, null).getAdditions().query(InstallableUnitQuery.ANY, new Collector(), new NullProgressMonitor()).size());
+		assertEquals(1, new ProvisioningPlan(Status.OK_STATUS, ops, null, null).getAdditions().query(InstallableUnitQuery.ANY, new Collector(), new NullProgressMonitor()).size());
 	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/SimpleSingleton.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/SimpleSingleton.java
index 3448ba7f5..6a24664a7 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/SimpleSingleton.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/planner/SimpleSingleton.java
@@ -9,10 +9,10 @@
 package org.eclipse.equinox.p2.tests.planner;
 
 import org.eclipse.core.runtime.IStatus;
+import org.eclipse.equinox.internal.p2.director.Explanation;
 import org.eclipse.equinox.internal.provisional.p2.core.Version;
 import org.eclipse.equinox.internal.provisional.p2.core.VersionRange;
-import org.eclipse.equinox.internal.provisional.p2.director.IPlanner;
-import org.eclipse.equinox.internal.provisional.p2.director.ProfileChangeRequest;
+import org.eclipse.equinox.internal.provisional.p2.director.*;
 import org.eclipse.equinox.internal.provisional.p2.engine.IProfile;
 import org.eclipse.equinox.internal.provisional.p2.metadata.*;
 import org.eclipse.equinox.p2.tests.AbstractProvisioningTest;
@@ -49,4 +49,13 @@ public class SimpleSingleton extends AbstractProvisioningTest {
 		req.addInstallableUnits(new IInstallableUnit[] {y});
 		assertEquals(IStatus.ERROR, planner.getProvisioningPlan(req, null, null).getStatus().getSeverity());
 	}
+
+	public void testExplanation() {
+		ProfileChangeRequest req = new ProfileChangeRequest(profile);
+		req.addInstallableUnits(new IInstallableUnit[] {y});
+		ProvisioningPlan plan = planner.getProvisioningPlan(req, null, null);
+		assertEquals(IStatus.ERROR, plan.getStatus().getSeverity());
+		assertEquals(Explanation.VIOLATED_SINGLETON_CONSTRAINT, plan.getRequestStatus().getShortExplanation());
+		assertTrue(plan.getRequestStatus().getConflictsWithInstalledRoots().contains(y));
+	}
 }