### Eclipse Workspace Patch 1.0
#P org.eclipse.equinox.p2.director
Index: src/org/eclipse/equinox/internal/p2/director/Explanation.java
===================================================================
RCS file: /cvsroot/rt/org.eclipse.equinox/p2/bundles/org.eclipse.equinox.p2.director/src/org/eclipse/equinox/internal/p2/director/Explanation.java,v
retrieving revision 1.12
diff -u -r1.12 Explanation.java
--- src/org/eclipse/equinox/internal/p2/director/Explanation.java	26 Apr 2010 00:55:03 -0000	1.12
+++ src/org/eclipse/equinox/internal/p2/director/Explanation.java	26 Apr 2010 14:06:32 -0000
@@ -116,13 +116,35 @@
 		}
 	}
 
+	public static class NotInstallableRoot extends Explanation {
+		public final IRequirement req;
+
+		public NotInstallableRoot(IRequirement req) {
+			this.req = req;
+		}
+
+		public String toString() {
+			return NLS.bind(Messages.Explanation_missingRootFilter, req);
+		}
+
+		public IStatus toStatus() {
+			return new Status(IStatus.ERROR, DirectorActivator.PI_DIRECTOR, NLS.bind(Messages.Explanation_missingRootFilter, req));
+		}
+
+		protected int orderValue() {
+			return 2;
+		}
+	}
+
 	public static class MissingIU extends Explanation {
 		public final IInstallableUnit iu;
 		public final IRequirement req;
+		public boolean isEntryPoint;
 
-		public MissingIU(IInstallableUnit iu, IRequirement req) {
+		public MissingIU(IInstallableUnit iu, IRequirement req, boolean isEntryPoint) {
 			this.iu = iu;
 			this.req = req;
+			this.isEntryPoint = isEntryPoint;
 		}
 
 		public int orderValue() {
@@ -134,6 +156,9 @@
 		}
 
 		public String toString() {
+			if (isEntryPoint) {
+				return NLS.bind(Messages.Explanation_missingRootRequired, req);
+			}
 			if (req.getFilter() == null) {
 				return NLS.bind(Messages.Explanation_missingRequired, iu, req);
 			}
@@ -141,6 +166,9 @@
 		}
 
 		public IStatus toStatus() {
+			if (isEntryPoint) {
+				return new Status(IStatus.ERROR, DirectorActivator.PI_DIRECTOR, NLS.bind(Messages.Explanation_missingRootRequired, req));
+			}
 			if (req.getFilter() == null) {
 				return new Status(IStatus.ERROR, DirectorActivator.PI_DIRECTOR, NLS.bind(Messages.Explanation_missingRequired, getUserReadableName(iu), req));
 			}
Index: src/org/eclipse/equinox/internal/p2/director/Messages.java
===================================================================
RCS file: /cvsroot/rt/org.eclipse.equinox/p2/bundles/org.eclipse.equinox.p2.director/src/org/eclipse/equinox/internal/p2/director/Messages.java,v
retrieving revision 1.25
diff -u -r1.25 Messages.java
--- src/org/eclipse/equinox/internal/p2/director/Messages.java	26 Apr 2010 00:55:02 -0000	1.25
+++ src/org/eclipse/equinox/internal/p2/director/Messages.java	26 Apr 2010 14:06:32 -0000
@@ -39,8 +39,10 @@
 	public static String Explanation_hardDependency;
 	public static String Explanation_patchedHardDependency;
 	public static String Explanation_missingRequired;
+	public static String Explanation_missingRootRequired;
 	public static String Explanation_missingNonGreedyRequired;
 	public static String Explanation_missingRequiredFilter;
+	public static String Explanation_missingRootFilter;
 	public static String Explanation_optionalDependency;
 	public static String Explanation_rootMissing;
 	public static String Explanation_rootSingleton;
Index: src/org/eclipse/equinox/internal/p2/director/Projector.java
===================================================================
RCS file: /cvsroot/rt/org.eclipse.equinox/p2/bundles/org.eclipse.equinox.p2.director/src/org/eclipse/equinox/internal/p2/director/Projector.java,v
retrieving revision 1.64
diff -u -r1.64 Projector.java
--- src/org/eclipse/equinox/internal/p2/director/Projector.java	26 Apr 2010 00:55:02 -0000	1.64
+++ src/org/eclipse/equinox/internal/p2/director/Projector.java	26 Apr 2010 14:06:32 -0000
@@ -19,6 +19,7 @@
 import org.eclipse.core.runtime.jobs.Job;
 import org.eclipse.equinox.internal.p2.core.helpers.CollectionUtils;
 import org.eclipse.equinox.internal.p2.core.helpers.Tracing;
+import org.eclipse.equinox.internal.p2.director.Explanation.NotInstallableRoot;
 import org.eclipse.equinox.internal.p2.metadata.IRequiredCapability;
 import org.eclipse.equinox.internal.p2.metadata.InstallableUnit;
 import org.eclipse.equinox.p2.metadata.*;
@@ -368,7 +369,7 @@
 		if (DEBUG) {
 			Tracing.debug(iu + "=0"); //$NON-NLS-1$
 		}
-		dependencyHelper.setFalse(iu, new Explanation.MissingIU(iu, req));
+		dependencyHelper.setFalse(iu, new Explanation.MissingIU(iu, req, iu == this.entryPoint));
 	}
 
 	// Check whether the requirement is applicable
@@ -416,7 +417,11 @@
 		}
 		if (req.getMin() > 0) {
 			if (matches.isEmpty()) {
-				missingRequirement(iu, req);
+				if (iu == entryPoint && emptyBecauseFiltered) {
+					dependencyHelper.setFalse(iu, new NotInstallableRoot(req));
+				} else {
+					missingRequirement(iu, req);
+				}
 			} else {
 				if (req.isGreedy()) {
 					IInstallableUnit reqIu = matches.get(0);
@@ -501,6 +506,11 @@
 			iuSlice = new HashMap<Version, IInstallableUnit>();
 			slice.put(iu.getId(), iuSlice);
 		}
+		IInstallableUnit alreadyProcessed = iuSlice.get(iu.getVersion());
+		if (alreadyProcessed != null) {
+			assert alreadyProcessed == iu;
+			return;
+		}
 		iuSlice.put(iu.getVersion(), iu);
 		if (!isApplicable(iu)) {
 			createNegation(iu, null);
@@ -853,6 +863,8 @@
 		createNegation(iu, req);
 	}
 
+	private boolean emptyBecauseFiltered;
+
 	/**
 	 * @param req
 	 * @return a list of mandatory requirements if any, an empty list if req.isOptional().
@@ -866,6 +878,7 @@
 				target.add(match);
 			}
 		}
+		emptyBecauseFiltered = !matches.isEmpty() && target.isEmpty();
 		return target;
 	}
 
Index: src/org/eclipse/equinox/internal/p2/director/SimplePlanner.java
===================================================================
RCS file: /cvsroot/rt/org.eclipse.equinox/p2/bundles/org.eclipse.equinox.p2.director/src/org/eclipse/equinox/internal/p2/director/SimplePlanner.java,v
retrieving revision 1.122
diff -u -r1.122 SimplePlanner.java
--- src/org/eclipse/equinox/internal/p2/director/SimplePlanner.java	26 Apr 2010 00:55:02 -0000	1.122
+++ src/org/eclipse/equinox/internal/p2/director/SimplePlanner.java	26 Apr 2010 14:06:32 -0000
@@ -317,12 +317,12 @@
 
 			Slicer slicer = new Slicer(new QueryableArray(availableIUs), newSelectionContext, satisfyMetaRequirements(profileChangeRequest.getProfileProperties()));
 			IQueryable<IInstallableUnit> slice = slicer.slice(new IInstallableUnit[] {(IInstallableUnit) updatedPlan[0]}, sub.newChild(ExpandWork / 4));
-			slicer.getNonGreedyIUs();
 			if (slice == null) {
 				IProvisioningPlan plan = engine.createPlan(profile, context);
 				plan.setStatus(slicer.getStatus());
 				return plan;
 			}
+			slice = new CompoundQueryable<IInstallableUnit>(new IQueryable[] {slice, new QueryableArray(profileChangeRequest.getAdditions().toArray(new IInstallableUnit[profileChangeRequest.getAdditions().size()]))});
 			Projector projector = new Projector(slice, newSelectionContext, slicer.getNonGreedyIUs(), satisfyMetaRequirements(profileChangeRequest.getProfileProperties()));
 			projector.encode((IInstallableUnit) updatedPlan[0], (IInstallableUnit[]) updatedPlan[1], profile, profileChangeRequest.getAdditions(), sub.newChild(ExpandWork / 4));
 			IStatus s = projector.invokeSolver(sub.newChild(ExpandWork / 4));
Index: src/org/eclipse/equinox/internal/p2/director/Slicer.java
===================================================================
RCS file: /cvsroot/rt/org.eclipse.equinox/p2/bundles/org.eclipse.equinox.p2.director/src/org/eclipse/equinox/internal/p2/director/Slicer.java,v
retrieving revision 1.27
diff -u -r1.27 Slicer.java
--- src/org/eclipse/equinox/internal/p2/director/Slicer.java	26 Apr 2010 00:55:03 -0000	1.27
+++ src/org/eclipse/equinox/internal/p2/director/Slicer.java	26 Apr 2010 14:06:32 -0000
@@ -85,7 +85,7 @@
 	private void validateInput(IInstallableUnit[] ius) {
 		for (int i = 0; i < ius.length; i++) {
 			if (!isApplicable(ius[i]))
-				throw new IllegalStateException("The IU " + ius[i] + " can't be installed in this environment because its filter does not match."); //$NON-NLS-1$//$NON-NLS-2$
+				throw new IllegalStateException(NLS.bind(Messages.Explanation_missingRootFilter, ius[i]));
 		}
 	}
 
Index: src/org/eclipse/equinox/internal/p2/director/messages.properties
===================================================================
RCS file: /cvsroot/rt/org.eclipse.equinox/p2/bundles/org.eclipse.equinox.p2.director/src/org/eclipse/equinox/internal/p2/director/messages.properties,v
retrieving revision 1.31
diff -u -r1.31 messages.properties
--- src/org/eclipse/equinox/internal/p2/director/messages.properties	26 Apr 2010 00:55:02 -0000	1.31
+++ src/org/eclipse/equinox/internal/p2/director/messages.properties	26 Apr 2010 14:06:32 -0000
@@ -25,8 +25,10 @@
 Explanation_hardDependency=Cannot satisfy dependency: {0} depends on: {1}
 Explanation_patchedHardDependency=Cannot satisfy patched ({0}) dependency: {1} depends on: {2}
 Explanation_missingRequired=Missing requirement: {0} requires ''{1}'' but it could not be found
+Explanation_missingRootRequired=You requested to install ''{0}'' but it could not be found
 Explanation_missingNonGreedyRequired=Missing non greedy requirement: ''{0}'' is required non greedily but it could not be found
 Explanation_missingRequiredFilter=Missing requirement for filter {0}: {1} requires ''{2}'' but it could not be found
+Explanation_missingRootFilter={0} can't be installed in this environment because its filter is not applicable.
 Explanation_optionalDependency=Optional dependency
 Explanation_rootMissing=Cannot complete the install because one or more required items could not be found.
 Explanation_rootSingleton=Cannot complete the install because of a conflicting dependency.