Auto-ignore derived resources

Automatically ignore derived resources. Register a resource change
listener to detect resources marked as derived asynchronously.
Auto-ignore can be switched off using a new preference.

Bug: 297674
Change-Id: I02d0e12e9bee94b1121a1fa57eedfc268dd8e5ef
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Signed-off-by: Robin Stocker <robin@nibor.org>

14 files changed, 206 insertions, 6 deletions

diff --git a/org.eclipse.egit.core.test/src/org/eclipse/egit/core/test/GitTestCase.java b/org.eclipse.egit.core.test/src/org/eclipse/egit/core/test/GitTestCase.java
index 00e5316c62..722726b626 100644
--- a/org.eclipse.egit.core.test/src/org/eclipse/egit/core/test/GitTestCase.java
+++ b/org.eclipse.egit.core.test/src/org/eclipse/egit/core/test/GitTestCase.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (C) 2007, Robin Rosenberg <robin.rosenberg@dewire.com>
+ * Copyright (C) 2007, 2013 Robin Rosenberg <robin.rosenberg@dewire.com> and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
@@ -15,7 +15,10 @@ import java.io.IOException;
 
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.ResourcesPlugin;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences;
+import org.eclipse.core.runtime.preferences.InstanceScope;
 import org.eclipse.egit.core.Activator;
+import org.eclipse.egit.core.GitCorePreferences;
 import org.eclipse.jgit.junit.MockSystemReader;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ObjectId;
@@ -26,6 +29,7 @@ import org.eclipse.jgit.util.IO;
 import org.eclipse.jgit.util.SystemReader;
 import org.junit.After;
 import org.junit.Before;
+import org.junit.BeforeClass;
 
 public abstract class GitTestCase {
 
@@ -35,6 +39,14 @@ public abstract class GitTestCase {
 
 	protected File gitDir;
 
+	@BeforeClass
+	public static void setUpClass() {
+		// suppress auto-ignoring to avoid interference
+		IEclipsePreferences p = InstanceScope.INSTANCE.getNode(Activator
+				.getPluginId());
+		p.putBoolean(GitCorePreferences.core_autoIgnoreDerivedResources, false);
+	}
+
 	@Before
 	public void setUp() throws Exception {
 		// ensure there are no shared Repository instances left
diff --git a/org.eclipse.egit.core.test/src/org/eclipse/egit/core/test/TestProject.java b/org.eclipse.egit.core.test/src/org/eclipse/egit/core/test/TestProject.java
index f6808ea6df..31e759ee3d 100644
--- a/org.eclipse.egit.core.test/src/org/eclipse/egit/core/test/TestProject.java
+++ b/org.eclipse.egit.core.test/src/org/eclipse/egit/core/test/TestProject.java
@@ -2,6 +2,7 @@
  * Copyright (C) 2007, Robin Rosenberg <robin.rosenberg@dewire.com>
  * Copyright (C) 2006, Shawn O. Pearce <spearce@spearce.org>
  * Copyright (C) 2012, Robin Stocker <robin@nibor.org>
+ * Copyright (C) 2013, Matthias Sohn <matthias.sohn@sap.com>
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
@@ -51,6 +52,8 @@ public class TestProject {
 
 	private final File workspaceSupplement;
 
+	private IFolder binFolder;
+
 	/**
 	 * @throws CoreException
 	 *             If project already exists
@@ -96,13 +99,17 @@ public class TestProject {
 		project.create(description, null);
 		project.open(null);
 		javaProject = JavaCore.create(project);
-		IFolder binFolder = createBinFolder();
+		binFolder = createBinFolder();
 		setJavaNature();
 		javaProject.setRawClasspath(new IClasspathEntry[0], null);
 		createOutputFolder(binFolder);
 		addSystemLibraries();
 	}
 
+	public void setBinFolderDerived() throws CoreException {
+		binFolder.setDerived(true, null);
+	}
+
 	public File getWorkspaceSupplement() {
 		return workspaceSupplement;
 	}
diff --git a/org.eclipse.egit.core.test/src/org/eclipse/egit/core/test/op/ConnectProviderOperationTest.java b/org.eclipse.egit.core.test/src/org/eclipse/egit/core/test/op/ConnectProviderOperationTest.java
index b4f80f18e5..6992908bed 100644
--- a/org.eclipse.egit.core.test/src/org/eclipse/egit/core/test/op/ConnectProviderOperationTest.java
+++ b/org.eclipse.egit.core.test/src/org/eclipse/egit/core/test/op/ConnectProviderOperationTest.java
@@ -1,6 +1,7 @@
 /*******************************************************************************
  * Copyright (C) 2007, Robin Rosenberg <robin.rosenberg@dewire.com>
  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
+ * Copyright (C) 2013, Matthias Sohn <matthias.sohn@sap.com>
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
@@ -20,6 +21,14 @@ import java.io.IOException;
 
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IPath;
+import org.eclipse.core.runtime.jobs.Job;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences;
+import org.eclipse.core.runtime.preferences.InstanceScope;
+import org.eclipse.egit.core.Activator;
+import org.eclipse.egit.core.GitCorePreferences;
+import org.eclipse.egit.core.JobFamilies;
+import org.eclipse.egit.core.RepositoryUtil;
 import org.eclipse.egit.core.op.ConnectProviderOperation;
 import org.eclipse.egit.core.test.GitTestCase;
 import org.eclipse.egit.core.test.TestRepository;
@@ -58,6 +67,29 @@ public class ConnectProviderOperationTest extends GitTestCase {
 	}
 
 	@Test
+	public void testAutoIgnoresDerivedFolder() throws Exception {
+		// enable auto-ignore
+		IEclipsePreferences p = InstanceScope.INSTANCE.getNode(Activator
+				.getPluginId());
+		p.putBoolean(GitCorePreferences.core_autoIgnoreDerivedResources, true);
+		Repository repository = new FileRepository(gitDir);
+		repository.create();
+		repository.close();
+		project.setBinFolderDerived();
+		ConnectProviderOperation operation = new ConnectProviderOperation(
+				project.getProject(), gitDir);
+		operation.execute(null);
+
+		assertTrue(RepositoryProvider.isShared(project.getProject()));
+		Job.getJobManager().join(JobFamilies.AUTO_IGNORE, null);
+
+		IPath binPath = project.getProject().getLocation().append("bin");
+		assertTrue(RepositoryUtil.isIgnored(binPath));
+		assertTrue(gitDir.exists());
+		p.putBoolean(GitCorePreferences.core_autoIgnoreDerivedResources, false);
+	}
+
+	@Test
 	public void testNewUnsharedFile() throws CoreException, Exception {
 
 		project.createSourceFolder();
diff --git a/org.eclipse.egit.core/src/org/eclipse/egit/core/Activator.java b/org.eclipse.egit.core/src/org/eclipse/egit/core/Activator.java
index d37f450f89..da526798b5 100644
--- a/org.eclipse.egit.core/src/org/eclipse/egit/core/Activator.java
+++ b/org.eclipse.egit.core/src/org/eclipse/egit/core/Activator.java
@@ -1,7 +1,7 @@
 /*******************************************************************************
  * Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
- * Copyright (C) 2011, Matthias Sohn <matthias.sohn@sap.com>
+ * Copyright (C) 2011, 2013 Matthias Sohn <matthias.sohn@sap.com>
  * Copyright (C) 2013, Robin Stocker <robin@nibor.org>
  *
  * All rights reserved. This program and the accompanying materials
@@ -12,9 +12,13 @@
 package org.eclipse.egit.core;
 
 import java.io.File;
+import java.io.IOException;
+import java.text.MessageFormat;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Dictionary;
 import java.util.Hashtable;
+import java.util.List;
 
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IResource;
@@ -24,6 +28,7 @@ import org.eclipse.core.resources.IResourceDelta;
 import org.eclipse.core.resources.IResourceDeltaVisitor;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.NullProgressMonitor;
 import org.eclipse.core.runtime.Plugin;
@@ -35,6 +40,7 @@ import org.eclipse.egit.core.internal.indexdiff.IndexDiffCache;
 import org.eclipse.egit.core.internal.job.JobUtil;
 import org.eclipse.egit.core.internal.trace.GitTraceLocation;
 import org.eclipse.egit.core.op.ConnectProviderOperation;
+import org.eclipse.egit.core.op.IgnoreOperation;
 import org.eclipse.egit.core.project.GitProjectData;
 import org.eclipse.egit.core.project.RepositoryFinder;
 import org.eclipse.egit.core.project.RepositoryMapping;
@@ -60,6 +66,7 @@ public class Activator extends Plugin implements DebugOptionsListener {
 	private EGitSecureStore secureStore;
 	private AutoShareProjects shareGitProjectsJob;
 	private IResourceChangeListener preDeleteProjectListener;
+	private IgnoreDerivedResources ignoreDerivedResourcesListener;
 
 	/**
 	 * @return the singleton {@link Activator}
@@ -138,6 +145,7 @@ public class Activator extends Plugin implements DebugOptionsListener {
 		secureStore = new EGitSecureStore(SecurePreferencesFactory.getDefault());
 
 		registerAutoShareProjects();
+		registerAutoIgnoreDerivedResources();
 		registerPreDeleteResourceChangeListener();
 	}
 
@@ -208,6 +216,11 @@ public class Activator extends Plugin implements DebugOptionsListener {
 			ResourcesPlugin.getWorkspace().removeResourceChangeListener(preDeleteProjectListener);
 			preDeleteProjectListener = null;
 		}
+		if (ignoreDerivedResourcesListener != null) {
+			ResourcesPlugin.getWorkspace().removeResourceChangeListener(
+					ignoreDerivedResourcesListener);
+			ignoreDerivedResourcesListener = null;
+		}
 	}
 
 	private void registerAutoShareProjects() {
@@ -291,4 +304,75 @@ public class Activator extends Plugin implements DebugOptionsListener {
 			}
 		}
 	}
+
+	private void registerAutoIgnoreDerivedResources() {
+		ignoreDerivedResourcesListener = new IgnoreDerivedResources();
+		ResourcesPlugin.getWorkspace().addResourceChangeListener(
+				ignoreDerivedResourcesListener,
+				IResourceChangeEvent.POST_CHANGE);
+	}
+
+	private static class IgnoreDerivedResources implements
+			IResourceChangeListener {
+
+		protected boolean autoIgnoreDerived() {
+			IEclipsePreferences d = DefaultScope.INSTANCE.getNode(Activator
+					.getPluginId());
+			IEclipsePreferences p = InstanceScope.INSTANCE.getNode(Activator
+					.getPluginId());
+			return p.getBoolean(
+					GitCorePreferences.core_autoIgnoreDerivedResources,
+					d.getBoolean(
+							GitCorePreferences.core_autoIgnoreDerivedResources,
+							true));
+		}
+
+		public void resourceChanged(IResourceChangeEvent event) {
+			try {
+				IResourceDelta d = event.getDelta();
+				if (d == null || !autoIgnoreDerived())
+					return;
+
+				final List<IPath> toBeIgnored = new ArrayList<IPath>();
+
+				d.accept(new IResourceDeltaVisitor() {
+
+					public boolean visit(IResourceDelta delta)
+							throws CoreException {
+						if ((delta.getKind() & (IResourceDelta.ADDED | IResourceDelta.CHANGED)) == 0)
+							return false;
+						int flags = delta.getFlags();
+						if ((flags != 0)
+								&& ((flags & IResourceDelta.DERIVED_CHANGED) == 0))
+							return false;
+
+						final IResource r = delta.getResource();
+						if (r.isTeamPrivateMember())
+							return false;
+
+						if (r.isDerived()) {
+							try {
+								if (!RepositoryUtil.isIgnored(r.getLocation()))
+									toBeIgnored.add(r.getLocation());
+							} catch (IOException e) {
+								logError(
+										MessageFormat.format(
+												CoreText.Activator_ignoreResourceFailed,
+												r.getFullPath()), e);
+							}
+							return false;
+						}
+						return true;
+					}
+				});
+				if (toBeIgnored.size() > 0)
+					JobUtil.scheduleUserJob(new IgnoreOperation(toBeIgnored),
+							CoreText.Activator_autoIgnoreDerivedResources,
+							JobFamilies.AUTO_IGNORE);
+			} catch (CoreException e) {
+				Activator.logError(e.getMessage(), e);
+				return;
+			}
+		}
+	}
 }
diff --git a/org.eclipse.egit.core/src/org/eclipse/egit/core/CoreText.java b/org.eclipse.egit.core/src/org/eclipse/egit/core/CoreText.java
index aa5b3c5e6e..9a7675dc47 100644
--- a/org.eclipse.egit.core/src/org/eclipse/egit/core/CoreText.java
+++ b/org.eclipse.egit.core/src/org/eclipse/egit/core/CoreText.java
@@ -3,6 +3,7 @@
  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
  * Copyright (C) 2012, Robin Stocker <robin@nibor.org>
  * Copyright (C) 2012, Markus Duft <markus.duft@salomon.at>
+ * Copyright (C) 2013, Matthias Sohn <matthias.sohn@sap.com>
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
@@ -26,12 +27,18 @@ public class CoreText extends NLS {
 	private static final String BUNDLE_NAME = "org.eclipse.egit.core.coretext"; //$NON-NLS-1$
 
 	/** */
+	public static String Activator_autoIgnoreDerivedResources;
+
+	/** */
 	public static String Activator_AutoShareJobName;
 
 	/** */
 	public static String Activator_AutoSharingFailed;
 
 	/** */
+	public static String Activator_ignoreResourceFailed;
+
+	/** */
 	public static String Activator_ReconfigureWindowCacheError;
 
 	/** */
diff --git a/org.eclipse.egit.core/src/org/eclipse/egit/core/GitCorePreferenceInitializer.java b/org.eclipse.egit.core/src/org/eclipse/egit/core/GitCorePreferenceInitializer.java
index 237a0eac1c..0c7bfec679 100644
--- a/org.eclipse.egit.core/src/org/eclipse/egit/core/GitCorePreferenceInitializer.java
+++ b/org.eclipse.egit.core/src/org/eclipse/egit/core/GitCorePreferenceInitializer.java
@@ -1,6 +1,7 @@
 /*******************************************************************************
  * Copyright (C) 2008, Roger C. Soares <rogersoares@intelinet.com.br>
  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
+ * Copyright (C) 2013, Matthias Sohn <matthias.sohn@sap.com>
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
@@ -26,5 +27,6 @@ public class GitCorePreferenceInitializer extends AbstractPreferenceInitializer
 		p.putInt(GitCorePreferences.core_deltaBaseCacheLimit, 10 * MB);
 		p.putInt(GitCorePreferences.core_streamFileThreshold, 50 * MB);
 		p.putBoolean(GitCorePreferences.core_autoShareProjects, false);
+		p.putBoolean(GitCorePreferences.core_autoIgnoreDerivedResources, true);
 	}
 }
diff --git a/org.eclipse.egit.core/src/org/eclipse/egit/core/GitCorePreferences.java b/org.eclipse.egit.core/src/org/eclipse/egit/core/GitCorePreferences.java
index edb2d354a7..14c0a40e82 100644
--- a/org.eclipse.egit.core/src/org/eclipse/egit/core/GitCorePreferences.java
+++ b/org.eclipse.egit.core/src/org/eclipse/egit/core/GitCorePreferences.java
@@ -1,6 +1,7 @@
 /*******************************************************************************
  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
  * Copyright (C) 2011, Robin Rosenberg
+ * Copyright (C) 2013, Matthias Sohn <matthias.sohn@sap.com>
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
@@ -30,6 +31,9 @@ public class GitCorePreferences {
 	public static final String core_autoShareProjects =
 		"core_autoShareProjects";  //$NON-NLS-1$
 	/** */
+	public static final String core_autoIgnoreDerivedResources =
+		"core_autoIgnoreDerivedResources"; //$NON-NLS-1$
+	/** */
 	public static final String core_gitPrefix =
 		"core_gitPrefix"; //$NON-NLS-1$
 }
diff --git a/org.eclipse.egit.core/src/org/eclipse/egit/core/JobFamilies.java b/org.eclipse.egit.core/src/org/eclipse/egit/core/JobFamilies.java
index 84388a90d9..698b7d4026 100644
--- a/org.eclipse.egit.core/src/org/eclipse/egit/core/JobFamilies.java
+++ b/org.eclipse.egit.core/src/org/eclipse/egit/core/JobFamilies.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (C) 2011, Matthias Sohn <matthias.sohn@sap.com>
+ * Copyright (C) 2011, 2013 Matthias Sohn <matthias.sohn@sap.com> and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
@@ -28,4 +28,9 @@ public class JobFamilies {
 	 * Job family for auto share job
 	 */
 	public static final Object AUTO_SHARE = new Object();
+
+	/**
+	 * Job family for auto ignore job
+	 */
+	public static final Object AUTO_IGNORE = new Object();
 }
diff --git a/org.eclipse.egit.core/src/org/eclipse/egit/core/coretext.properties b/org.eclipse.egit.core/src/org/eclipse/egit/core/coretext.properties
index eb4dab52a0..19d3d94337 100644
--- a/org.eclipse.egit.core/src/org/eclipse/egit/core/coretext.properties
+++ b/org.eclipse.egit.core/src/org/eclipse/egit/core/coretext.properties
@@ -32,8 +32,10 @@ DeleteResourcesOperation_deleteFailed=Deleting resource {0} failed.
 DeleteResourcesOperation_deleteFailedSeeLog=Deleting resources failed. See log for details
 DisconnectProviderOperation_disconnecting=Disconnecting Git team provider.
 
+Activator_autoIgnoreDerivedResources=Auto-ignore derived resources
 Activator_AutoShareJobName=Auto share git projects
 Activator_AutoSharingFailed=Auto sharing project with git failed
+Activator_ignoreResourceFailed=Ignoring {0} failed
 Activator_ReconfigureWindowCacheError=Exception when reconfiguring window cache from configuration, default configuration will be used
 
 AssumeUnchangedOperation_adding=Marking resources unchanged
diff --git a/org.eclipse.egit.core/src/org/eclipse/egit/core/op/ConnectProviderOperation.java b/org.eclipse.egit.core/src/org/eclipse/egit/core/op/ConnectProviderOperation.java
index 4dfb0fc55b..4370e6c406 100644
--- a/org.eclipse.egit.core/src/org/eclipse/egit/core/op/ConnectProviderOperation.java
+++ b/org.eclipse.egit.core/src/org/eclipse/egit/core/op/ConnectProviderOperation.java
@@ -2,6 +2,7 @@
  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
  * Copyright (C) 2008, Google Inc.
  * Copyright (C) 2009, Mykola Nikishov <mn@mn.com.ua>
+ * Copyright (C) 2013, Matthias Sohn <matthias.sohn@sap.com>
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
@@ -12,16 +13,20 @@ package org.eclipse.egit.core.op;
 
 import java.io.File;
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
+import org.eclipse.core.resources.IContainer;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IResource;
 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.MultiStatus;
@@ -146,6 +151,7 @@ public class ConnectProviderOperation implements IEGitOperation {
 					}
 					RepositoryProvider
 							.map(project, GitProvider.class.getName());
+					autoIgnoreDerivedResources(project, monitor);
 					project.refreshLocal(IResource.DEPTH_INFINITE,
 							new SubProgressMonitor(monitor, 50));
 					monitor.worked(10);
@@ -164,6 +170,29 @@ public class ConnectProviderOperation implements IEGitOperation {
 		}
 	}
 
+	private void autoIgnoreDerivedResources(IProject project,
+			IProgressMonitor monitor) throws CoreException {
+		List<IPath> paths = findDerivedResources(project);
+		if (paths.size() > 0) {
+			IgnoreOperation ignoreOp = new IgnoreOperation(paths);
+			IProgressMonitor subMonitor = new SubProgressMonitor(monitor, 1);
+			ignoreOp.execute(subMonitor);
+		}
+	}
+
+	private List<IPath> findDerivedResources(IContainer c)
+			throws CoreException {
+		List<IPath> derived = new ArrayList<IPath>();
+		IResource[] members = c.members(IContainer.INCLUDE_HIDDEN);
+		for (IResource r : members) {
+			if (r.isDerived())
+				derived.add(r.getLocation());
+			else if (r instanceof IContainer)
+				derived.addAll(findDerivedResources((IContainer) r));
+		}
+		return derived;
+	}
+
 	/* (non-Javadoc)
 	 * @see org.eclipse.egit.core.op.IEGitOperation#getSchedulingRule()
 	 */
diff --git a/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/common/LocalRepositoryTestCase.java b/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/common/LocalRepositoryTestCase.java
index 0b116353a1..d707c67262 100644
--- a/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/common/LocalRepositoryTestCase.java
+++ b/org.eclipse.egit.ui.test/src/org/eclipse/egit/ui/common/LocalRepositoryTestCase.java
@@ -28,7 +28,10 @@ import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IProjectDescription;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.Path;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences;
+import org.eclipse.core.runtime.preferences.InstanceScope;
 import org.eclipse.egit.core.Activator;
+import org.eclipse.egit.core.GitCorePreferences;
 import org.eclipse.egit.core.RepositoryCache;
 import org.eclipse.egit.core.op.AddToIndexOperation;
 import org.eclipse.egit.core.op.CloneOperation;
@@ -140,6 +143,11 @@ public abstract class LocalRepositoryTestCase extends EGitTestCase {
 		File repoRoot = new File(testDirectory, "RepositoryRoot");
 		if (!repoRoot.exists())
 			FileUtils.mkdir(repoRoot, true);
+		// suppress auto-ignoring to avoid interference
+		IEclipsePreferences corePrefs = InstanceScope.INSTANCE
+				.getNode(org.eclipse.egit.core.Activator.getPluginId());
+		corePrefs.putBoolean(
+				GitCorePreferences.core_autoIgnoreDerivedResources, false);
 		// make sure the default directory for Repos is not the user home
 		org.eclipse.egit.ui.Activator.getDefault().getPreferenceStore()
 				.setValue(UIPreferences.DEFAULT_REPO_DIR, repoRoot.getPath());
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java
index ed3fcaf983..b20f5aeaf8 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java
@@ -1,7 +1,7 @@
 /*******************************************************************************
  * Copyright (C) 2008, Roger C. Soares <rogersoares@intelinet.com.br>
  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
- * Copyright (C) 2010, Matthias Sohn <matthias.sohn@sap.com>
+ * Copyright (C) 2010, 2013 Matthias Sohn <matthias.sohn@sap.com>
  * Copyright (C) 2011, Daniel Megert <daniel_megert@ch.ibm.com>
  * Copyright (C) 2012, Mathias Kinzler <mathias.kinzler@sap.com>
  * Copyright (C) 2012, Daniel Megert <daniel_megert@ch.ibm.com>
@@ -642,6 +642,9 @@ public class UIText extends NLS {
 	public static String ProjectsPreferencePage_RestoreBranchProjects;
 
 	/** */
+	public static String ProjectsPreferencePage_AutoIgnoreDerivedResources;
+
+	/** */
 	public static String GitProjectPropertyPage_LabelBranch;
 
 	/** */
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/preferences/ProjectsPreferencePage.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/preferences/ProjectsPreferencePage.java
index 770ea560d6..11cd373b0b 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/preferences/ProjectsPreferencePage.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/preferences/ProjectsPreferencePage.java
@@ -51,5 +51,9 @@ public class ProjectsPreferencePage extends FieldEditorPreferencePage implements
 						.getPreferenceStore();
 			}
 		});
+		addField(new BooleanFieldEditor(
+				GitCorePreferences.core_autoIgnoreDerivedResources,
+				UIText.ProjectsPreferencePage_AutoIgnoreDerivedResources,
+				getFieldEditorParent()));
 	}
 }
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties
index 88259e29d9..6e825f59d5 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties
@@ -1,5 +1,5 @@
 ###############################################################################
-# Copyright (c) 2005, 2012 Shawn Pearce and others.
+# Copyright (c) 2005, 2013 Shawn Pearce and others.
 # All rights reserved. This program and the accompanying materials
 # are made available under the terms of the Eclipse Public License v1.0
 # which accompanies this distribution, and is available at
@@ -900,6 +900,7 @@ WindowCachePreferencePage_streamFileThreshold=Stream File Threshold:
 
 ProjectsPreferencePage_AutoShareProjects=Auto share projects located in a git repository
 ProjectsPreferencePage_RestoreBranchProjects=Track each branch's imported projects and restore on checkout
+ProjectsPreferencePage_AutoIgnoreDerivedResources=Automatically ignore derived resources by adding them to .gitignore
 
 RefreshPreferencesPage_RefreshOnlyWhenActive=Refresh only when workbench is &active
 RefreshPreferencesPage_RefreshWhenIndexChange=Refresh resources when &index changes