### Eclipse Workspace Patch 1.0
#P org.eclipse.team.cvs.core
Index: src/org/eclipse/team/internal/ccvs/core/client/listeners/DiffListener.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.team.cvs.core/src/org/eclipse/team/internal/ccvs/core/client/listeners/DiffListener.java,v
retrieving revision 1.18
diff -u -r1.18 DiffListener.java
--- src/org/eclipse/team/internal/ccvs/core/client/listeners/DiffListener.java	24 Apr 2009 09:33:21 -0000	1.18
+++ src/org/eclipse/team/internal/ccvs/core/client/listeners/DiffListener.java	1 Feb 2011 09:03:45 -0000
@@ -74,10 +74,10 @@
 			ICVSRepositoryLocation location, 
 			ICVSFolder commandRoot,
 			IProgressMonitor monitor) {
-		// ignore server messages for now - this is used only with the diff
-		// request and the errors can be safely ignored.
+		// return all the server errors as CVSStatus.ERROR_LINE or
+		// CVSStatus.PROTOCOL_ERROR
 		if (getServerMessage(line, location) != null) {
-			return OK;
+			return super.errorLine(line, location, commandRoot, monitor);
 		}
 		
 		//Check to see if this is a no such directory message
Index: src/org/eclipse/team/internal/ccvs/core/messages.properties
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.team.cvs.core/src/org/eclipse/team/internal/ccvs/core/messages.properties,v
retrieving revision 1.172
diff -u -r1.172 messages.properties
--- src/org/eclipse/team/internal/ccvs/core/messages.properties	24 Apr 2009 09:33:21 -0000	1.172
+++ src/org/eclipse/team/internal/ccvs/core/messages.properties	1 Feb 2011 09:03:45 -0000
@@ -261,4 +261,4 @@
 PrepareForReplaceVisitor_DeletedFileWithoutHistoryCannotBeRestoredWhileRevertToBase=Deleted file does not have history and cannot be restored with BASE tag.
 PrepareForReplaceVisitor_FileCannotBeReplacedWithBase=File {0} cannot be replaced with BASE.
 ThePatchDoesNotContainChangesFor_0= The patch does not contain changes for {0}
-ThePatchDoesNotContainAllTheChanges=The patch does not contain all the changes
\ No newline at end of file
+ThePatchDoesNotContainAllTheChanges=An error occurred while performing difference operation, the patch may not contain all the changes
\ No newline at end of file
#P org.eclipse.team.cvs.ui
Index: src/org/eclipse/team/internal/ccvs/ui/operations/DiffOperation.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.team.cvs.ui/src/org/eclipse/team/internal/ccvs/ui/operations/DiffOperation.java,v
retrieving revision 1.19
diff -u -r1.19 DiffOperation.java
--- src/org/eclipse/team/internal/ccvs/ui/operations/DiffOperation.java	21 Sep 2009 10:40:45 -0000	1.19
+++ src/org/eclipse/team/internal/ccvs/ui/operations/DiffOperation.java	1 Feb 2011 09:03:46 -0000
@@ -312,7 +312,10 @@
 		List toShow = new ArrayList();
 		IStatus children[] = status.getChildren();
 		for (int i = 0; i < children.length; i++) {
-			if (children[i].getCode() == CVSStatus.BINARY_FILES_DIFFER) {
+			// ignore all errors except those found by DiffListener
+			if (children[i].getCode() == CVSStatus.BINARY_FILES_DIFFER
+					|| children[i].getCode() == CVSStatus.PROTOCOL_ERROR
+					|| children[i].getCode() == CVSStatus.ERROR_LINE) {
 				toShow.add(children[i]);
 			}
 		}
#P org.eclipse.team.tests.cvs.core
Index: patchdata/server_response_with_error.txt
===================================================================
RCS file: patchdata/server_response_with_error.txt
diff -N patchdata/server_response_with_error.txt
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ patchdata/server_response_with_error.txt	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,16 @@
+M Index: src/Test1.java
+M ===================================================================
+M RCS file: /Eclipse_home/CVSREPO/test/src/Test1.java,v
+M retrieving revision 1.1
+M diff -u -r1.1 Test1.java
+M --- src/Test1.java	31 Jan 2011 16:19:33 -0000	1.1
+M +++ src/Test1.java	31 Jan 2011 17:48:38 -0000
+M @@ -1,4 +1,6 @@
+M  
+M  public class Test1 {
+M +	private void testMethod1() {
+M  
+M +	}
+M  }
+E cvs server: cannot find revision control file for src/Test2.java
+error  
\ No newline at end of file
Index: src/org/eclipse/team/tests/ccvs/ui/CreatePatchTest.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.team.tests.cvs.core/src/org/eclipse/team/tests/ccvs/ui/CreatePatchTest.java,v
retrieving revision 1.2
diff -u -r1.2 CreatePatchTest.java
--- src/org/eclipse/team/tests/ccvs/ui/CreatePatchTest.java	25 Feb 2010 10:22:34 -0000	1.2
+++ src/org/eclipse/team/tests/ccvs/ui/CreatePatchTest.java	1 Feb 2011 09:03:47 -0000
@@ -11,9 +11,11 @@
 package org.eclipse.team.tests.ccvs.ui;
 
 import java.io.BufferedReader;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.io.PrintStream;
 import java.net.URL;
 
 import junit.framework.Test;
@@ -26,7 +28,9 @@
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Path;
+import org.eclipse.core.runtime.Status;
 import org.eclipse.jface.wizard.IWizardPage;
 import org.eclipse.jface.wizard.WizardDialog;
 import org.eclipse.swt.SWT;
@@ -35,6 +39,12 @@
 import org.eclipse.swt.widgets.Event;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.swt.widgets.Text;
+import org.eclipse.team.internal.ccvs.core.CVSException;
+import org.eclipse.team.internal.ccvs.core.CVSStatus;
+import org.eclipse.team.internal.ccvs.core.ICVSFolder;
+import org.eclipse.team.internal.ccvs.core.client.Command;
+import org.eclipse.team.internal.ccvs.core.client.Session;
+import org.eclipse.team.internal.ccvs.core.client.listeners.DiffListener;
 import org.eclipse.team.internal.ccvs.ui.CVSUIMessages;
 import org.eclipse.team.internal.ccvs.ui.wizards.GenerateDiffFileWizard;
 import org.eclipse.team.tests.ccvs.core.EclipseTest;
@@ -279,4 +289,77 @@
 		return event;
 	}
 
+	public void testBug31661() throws FileNotFoundException, CoreException {
+
+		copyIntoWorkspace("server_response_with_error.txt",
+				"server_response_with_error.txt");
+
+		Session session = new Session(getRepository(),
+				(ICVSFolder) getCVSResource(testProject)) {
+			// Override the session so it always returns response with an error.
+			private BufferedReader serverResp = new BufferedReader(
+					new InputStreamReader(testProject.getFile(
+							"server_response_with_error.txt").getContents()));
+
+			private boolean isOpened = false;
+
+			public void open(IProgressMonitor monitor) throws CVSException {
+				super.open(monitor);
+				isOpened = true;
+			}
+
+			public String readLine() throws CVSException {
+				if (!isOpened) {
+					return super.readLine();
+				}
+				try {
+					return serverResp.readLine();
+				} catch (IOException e) {
+					throw new CVSException(new Status(IStatus.ERROR, null,
+							null, e));
+				}
+			}
+
+			public void close() {
+				try {
+					super.close();
+					serverResp.close();
+				} catch (IOException e) {
+					fail(e.getMessage());
+				}
+			}
+		};
+
+		PrintStream stream = new PrintStream(testProject
+				.getFile("/patch_with_error.txt").getLocation().toFile());
+
+		try {
+			session.open(getMonitor());
+
+			DiffListener diffListener = new DiffListener(stream);
+
+			IStatus status = Command.DIFF.execute(session,
+					Command.NO_GLOBAL_OPTIONS, new Command.LocalOption[0],
+					new String[0], diffListener, getMonitor());
+
+			assertNotNull(
+					"Diff command did not report error when some changes were excluded",
+					status);
+			assertEquals("Diff command did not report server error",
+					CVSStatus.SERVER_ERROR, status.getCode());
+
+			IStatus children[] = status.getChildren();
+			assertEquals("Diff command did not report any server errors", 1,
+					children.length);
+
+			assertEquals("Diff command did not report error line",
+					CVSStatus.ERROR_LINE, children[0].getCode());
+
+		} finally {
+			session.close();
+			stream.close();
+
+		}
+	}
+	
 }