Merge changes Idaed9310,I62bd7c0b

* changes:
  ObjectChecker: honor some git-core fsck.* options
  ObjectChecker: allow some objects to skip errors

8 files changed, 705 insertions, 168 deletions

diff --git a/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties b/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties
index 840059d34f..992e10bad6 100644
--- a/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties
+++ b/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties
@@ -126,14 +126,15 @@ connectionFailed=connection failed
 connectionTimeOut=Connection time out: {0}
 contextMustBeNonNegative=context must be >= 0
 corruptionDetectedReReadingAt=Corruption detected re-reading at {0}
+corruptObjectBadDate=bad date
+corruptObjectBadEmail=bad email
 corruptObjectBadStream=bad stream
 corruptObjectBadStreamCorruptHeader=bad stream, corrupt header
+corruptObjectBadTimezone=bad time zone
 corruptObjectDuplicateEntryNames=duplicate entry names
 corruptObjectGarbageAfterSize=garbage after size
 corruptObjectIncorrectLength=incorrect length
 corruptObjectIncorrectSorting=incorrectly sorted
-corruptObjectInvalidAuthor=invalid author
-corruptObjectInvalidCommitter=invalid committer
 corruptObjectInvalidEntryMode=invalid entry mode
 corruptObjectInvalidMode=invalid mode
 corruptObjectInvalidModeChar=invalid mode character
@@ -152,11 +153,11 @@ corruptObjectInvalidNameNul=invalid name 'NUL'
 corruptObjectInvalidNamePrn=invalid name 'PRN'
 corruptObjectInvalidObject=invalid object
 corruptObjectInvalidParent=invalid parent
-corruptObjectInvalidTagger=invalid tagger
 corruptObjectInvalidTree=invalid tree
 corruptObjectInvalidType=invalid type
 corruptObjectInvalidType2=invalid type {0}
 corruptObjectMalformedHeader=malformed header: {0}
+corruptObjectMissingEmail=missing email
 corruptObjectNameContainsByte=name contains byte 0x%x
 corruptObjectNameContainsChar=name contains '%c'
 corruptObjectNameContainsNullByte=name contains byte 0x00
@@ -182,6 +183,7 @@ corruptObjectPackfileChecksumIncorrect=Packfile checksum incorrect.
 corruptObjectTruncatedInMode=truncated in mode
 corruptObjectTruncatedInName=truncated in name
 corruptObjectTruncatedInObjectId=truncated in object id
+corruptObjectZeroId=entry points to null SHA-1
 couldNotCheckOutBecauseOfConflicts=Could not check out because of conflicts
 couldNotDeleteLockFileShouldNotHappen=Could not delete lock file. Should not happen
 couldNotDeleteTemporaryIndexFileShouldNotHappen=Could not delete temporary index file. Should not happen
@@ -433,6 +435,7 @@ noXMLParserAvailable=No XML parser available.
 objectAtHasBadZlibStream=Object at {0} in {1} has bad zlib stream
 objectAtPathDoesNotHaveId=Object at path "{0}" does not have an id assigned. All object ids must be assigned prior to writing a tree.
 objectIsCorrupt=Object {0} is corrupt: {1}
+objectIsCorrupt3={0}: object {1}: {2}
 objectIsNotA=Object {0} is not a {1}.
 objectNotFound=Object {0} not found.
 objectNotFoundIn=Object {0} not found in {1}.
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/errors/CorruptObjectException.java b/org.eclipse.jgit/src/org/eclipse/jgit/errors/CorruptObjectException.java
index c6ea093750..e4db40b889 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/errors/CorruptObjectException.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/errors/CorruptObjectException.java
@@ -49,8 +49,10 @@ package org.eclipse.jgit.errors;
 import java.io.IOException;
 import java.text.MessageFormat;
 
+import org.eclipse.jgit.annotations.Nullable;
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.lib.AnyObjectId;
+import org.eclipse.jgit.lib.ObjectChecker;
 import org.eclipse.jgit.lib.ObjectId;
 
 /**
@@ -59,6 +61,26 @@ import org.eclipse.jgit.lib.ObjectId;
 public class CorruptObjectException extends IOException {
 	private static final long serialVersionUID = 1L;
 
+	private ObjectChecker.ErrorType errorType;
+
+	/**
+	 * Report a specific error condition discovered in an object.
+	 *
+	 * @param type
+	 *            type of error
+	 * @param id
+	 *            identity of the bad object
+	 * @param why
+	 *            description of the error.
+	 * @since 4.2
+	 */
+	public CorruptObjectException(ObjectChecker.ErrorType type, AnyObjectId id,
+			String why) {
+		super(MessageFormat.format(JGitText.get().objectIsCorrupt3,
+				type.getMessageId(), id.name(), why));
+		this.errorType = type;
+	}
+
 	/**
 	 * Construct a CorruptObjectException for reporting a problem specified
 	 * object id
@@ -66,8 +88,8 @@ public class CorruptObjectException extends IOException {
 	 * @param id
 	 * @param why
 	 */
-	public CorruptObjectException(final AnyObjectId id, final String why) {
-		this(id.toObjectId(), why);
+	public CorruptObjectException(AnyObjectId id, String why) {
+		super(MessageFormat.format(JGitText.get().objectIsCorrupt, id.name(), why));
 	}
 
 	/**
@@ -77,7 +99,7 @@ public class CorruptObjectException extends IOException {
 	 * @param id
 	 * @param why
 	 */
-	public CorruptObjectException(final ObjectId id, final String why) {
+	public CorruptObjectException(ObjectId id, String why) {
 		super(MessageFormat.format(JGitText.get().objectIsCorrupt, id.name(), why));
 	}
 
@@ -87,7 +109,7 @@ public class CorruptObjectException extends IOException {
 	 *
 	 * @param why
 	 */
-	public CorruptObjectException(final String why) {
+	public CorruptObjectException(String why) {
 		super(why);
 	}
 
@@ -105,4 +127,15 @@ public class CorruptObjectException extends IOException {
 		super(why);
 		initCause(cause);
 	}
+
+	/**
+	 * Specific error condition identified by {@link ObjectChecker}.
+	 *
+	 * @return error condition or null.
+	 * @since 4.2
+	 */
+	@Nullable
+	public ObjectChecker.ErrorType getErrorType() {
+		return errorType;
+	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java
index c476f1773e..7740a2bb80 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java
@@ -185,14 +185,15 @@ public class JGitText extends TranslationBundle {
 	/***/ public String connectionTimeOut;
 	/***/ public String contextMustBeNonNegative;
 	/***/ public String corruptionDetectedReReadingAt;
+	/***/ public String corruptObjectBadDate;
+	/***/ public String corruptObjectBadEmail;
 	/***/ public String corruptObjectBadStream;
 	/***/ public String corruptObjectBadStreamCorruptHeader;
+	/***/ public String corruptObjectBadTimezone;
 	/***/ public String corruptObjectDuplicateEntryNames;
 	/***/ public String corruptObjectGarbageAfterSize;
 	/***/ public String corruptObjectIncorrectLength;
 	/***/ public String corruptObjectIncorrectSorting;
-	/***/ public String corruptObjectInvalidAuthor;
-	/***/ public String corruptObjectInvalidCommitter;
 	/***/ public String corruptObjectInvalidEntryMode;
 	/***/ public String corruptObjectInvalidMode;
 	/***/ public String corruptObjectInvalidModeChar;
@@ -211,11 +212,11 @@ public class JGitText extends TranslationBundle {
 	/***/ public String corruptObjectInvalidNamePrn;
 	/***/ public String corruptObjectInvalidObject;
 	/***/ public String corruptObjectInvalidParent;
-	/***/ public String corruptObjectInvalidTagger;
 	/***/ public String corruptObjectInvalidTree;
 	/***/ public String corruptObjectInvalidType;
 	/***/ public String corruptObjectInvalidType2;
 	/***/ public String corruptObjectMalformedHeader;
+	/***/ public String corruptObjectMissingEmail;
 	/***/ public String corruptObjectNameContainsByte;
 	/***/ public String corruptObjectNameContainsChar;
 	/***/ public String corruptObjectNameContainsNullByte;
@@ -241,6 +242,7 @@ public class JGitText extends TranslationBundle {
 	/***/ public String corruptObjectTruncatedInMode;
 	/***/ public String corruptObjectTruncatedInName;
 	/***/ public String corruptObjectTruncatedInObjectId;
+	/***/ public String corruptObjectZeroId;
 	/***/ public String corruptPack;
 	/***/ public String couldNotCheckOutBecauseOfConflicts;
 	/***/ public String couldNotDeleteLockFileShouldNotHappen;
@@ -492,6 +494,7 @@ public class JGitText extends TranslationBundle {
 	/***/ public String objectAtHasBadZlibStream;
 	/***/ public String objectAtPathDoesNotHaveId;
 	/***/ public String objectIsCorrupt;
+	/***/ public String objectIsCorrupt3;
 	/***/ public String objectIsNotA;
 	/***/ public String objectNotFound;
 	/***/ public String objectNotFoundIn;
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/LazyObjectIdSetFile.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/LazyObjectIdSetFile.java
new file mode 100644
index 0000000000..1e2617c0e3
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/LazyObjectIdSetFile.java
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2015, Google Inc.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.internal.storage.file;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.Reader;
+
+import org.eclipse.jgit.lib.AnyObjectId;
+import org.eclipse.jgit.lib.MutableObjectId;
+import org.eclipse.jgit.lib.ObjectIdOwnerMap;
+import org.eclipse.jgit.lib.ObjectIdSet;
+
+/** Lazily loads a set of ObjectIds, one per line. */
+public class LazyObjectIdSetFile implements ObjectIdSet {
+	private final File src;
+	private ObjectIdOwnerMap<Entry> set;
+
+	/**
+	 * Create a new lazy set from a file.
+	 *
+	 * @param src
+	 *            the source file.
+	 */
+	public LazyObjectIdSetFile(File src) {
+		this.src = src;
+	}
+
+	@Override
+	public boolean contains(AnyObjectId objectId) {
+		if (set == null) {
+			set = load();
+		}
+		return set.contains(objectId);
+	}
+
+	private ObjectIdOwnerMap<Entry> load() {
+		ObjectIdOwnerMap<Entry> r = new ObjectIdOwnerMap<>();
+		try (FileInputStream fin = new FileInputStream(src);
+				Reader rin = new InputStreamReader(fin, UTF_8);
+				BufferedReader br = new BufferedReader(rin)) {
+			MutableObjectId id = new MutableObjectId();
+			for (String line; (line = br.readLine()) != null;) {
+				id.fromString(line);
+				if (!r.contains(id)) {
+					r.add(new Entry(id));
+				}
+			}
+		} catch (IOException e) {
+			// Ignore IO errors accessing the lazy set.
+		}
+		return r;
+	}
+
+	static class Entry extends ObjectIdOwnerMap.Entry {
+		Entry(AnyObjectId id) {
+			super(id);
+		}
+	}
+}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectChecker.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectChecker.java
index 855d9d7509..858a0385d0 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectChecker.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectChecker.java
@@ -44,20 +44,56 @@
 
 package org.eclipse.jgit.lib;
 
-import static org.eclipse.jgit.util.RawParseUtils.match;
+import static org.eclipse.jgit.lib.Constants.OBJECT_ID_LENGTH;
+import static org.eclipse.jgit.lib.Constants.OBJECT_ID_STRING_LENGTH;
+import static org.eclipse.jgit.lib.Constants.OBJ_BAD;
+import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
+import static org.eclipse.jgit.lib.Constants.OBJ_COMMIT;
+import static org.eclipse.jgit.lib.Constants.OBJ_TAG;
+import static org.eclipse.jgit.lib.Constants.OBJ_TREE;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.BAD_DATE;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.BAD_EMAIL;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.BAD_OBJECT_SHA1;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.BAD_PARENT_SHA1;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.BAD_TIMEZONE;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.BAD_TREE_SHA1;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.BAD_UTF8;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.DUPLICATE_ENTRIES;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.EMPTY_NAME;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.FULL_PATHNAME;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.HAS_DOT;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.HAS_DOTDOT;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.HAS_DOTGIT;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.MISSING_AUTHOR;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.MISSING_COMMITTER;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.MISSING_EMAIL;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.MISSING_OBJECT;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.MISSING_SPACE_BEFORE_DATE;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.MISSING_TAG_ENTRY;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.MISSING_TREE;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.MISSING_TYPE_ENTRY;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.NULL_SHA1;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.TREE_NOT_SORTED;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.UNKNOWN_TYPE;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.WIN32_BAD_NAME;
+import static org.eclipse.jgit.lib.ObjectChecker.ErrorType.ZERO_PADDED_FILEMODE;
 import static org.eclipse.jgit.util.RawParseUtils.nextLF;
 import static org.eclipse.jgit.util.RawParseUtils.parseBase10;
 
 import java.text.MessageFormat;
 import java.text.Normalizer;
+import java.util.EnumSet;
 import java.util.HashSet;
 import java.util.Locale;
 import java.util.Set;
 
+import org.eclipse.jgit.annotations.NonNull;
+import org.eclipse.jgit.annotations.Nullable;
 import org.eclipse.jgit.errors.CorruptObjectException;
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.util.MutableInteger;
 import org.eclipse.jgit.util.RawParseUtils;
+import org.eclipse.jgit.util.StringUtils;
 
 /**
  * Verifies that an object is formatted correctly.
@@ -98,31 +134,135 @@ public class ObjectChecker {
 	/** Header "tagger " */
 	public static final byte[] tagger = Constants.encodeASCII("tagger "); //$NON-NLS-1$
 
-	private final MutableObjectId tempId = new MutableObjectId();
-
-	private final MutableInteger ptrout = new MutableInteger();
+	/**
+	 * Potential issues identified by the checker.
+	 *
+	 * @since 4.2
+	 */
+	public enum ErrorType {
+		// @formatter:off
+		// These names match git-core so that fsck section keys also match.
+		/***/ NULL_SHA1,
+		/***/ DUPLICATE_ENTRIES,
+		/***/ TREE_NOT_SORTED,
+		/***/ ZERO_PADDED_FILEMODE,
+		/***/ EMPTY_NAME,
+		/***/ FULL_PATHNAME,
+		/***/ HAS_DOT,
+		/***/ HAS_DOTDOT,
+		/***/ HAS_DOTGIT,
+		/***/ BAD_OBJECT_SHA1,
+		/***/ BAD_PARENT_SHA1,
+		/***/ BAD_TREE_SHA1,
+		/***/ MISSING_AUTHOR,
+		/***/ MISSING_COMMITTER,
+		/***/ MISSING_OBJECT,
+		/***/ MISSING_TREE,
+		/***/ MISSING_TYPE_ENTRY,
+		/***/ MISSING_TAG_ENTRY,
+		/***/ BAD_DATE,
+		/***/ BAD_EMAIL,
+		/***/ BAD_TIMEZONE,
+		/***/ MISSING_EMAIL,
+		/***/ MISSING_SPACE_BEFORE_DATE,
+		/***/ UNKNOWN_TYPE,
+
+		// These are unique to JGit.
+		/***/ WIN32_BAD_NAME,
+		/***/ BAD_UTF8;
+		// @formatter:on
+
+		/** @return camelCaseVersion of the name. */
+		public String getMessageId() {
+			String n = name();
+			StringBuilder r = new StringBuilder(n.length());
+			for (int i = 0; i < n.length(); i++) {
+				char c = n.charAt(i);
+				if (c != '_') {
+					r.append(StringUtils.toLowerCase(c));
+				} else {
+					r.append(n.charAt(++i));
+				}
+			}
+			return r.toString();
+		}
+	}
 
-	private boolean allowZeroMode;
+	private final MutableObjectId tempId = new MutableObjectId();
+	private final MutableInteger bufPtr = new MutableInteger();
 
+	private EnumSet<ErrorType> errors = EnumSet.allOf(ErrorType.class);
+	private ObjectIdSet skipList;
 	private boolean allowInvalidPersonIdent;
 	private boolean windows;
 	private boolean macosx;
 
 	/**
+	 * Enable accepting specific malformed (but not horribly broken) objects.
+	 *
+	 * @param objects
+	 *            collection of object names known to be broken in a non-fatal
+	 *            way that should be ignored by the checker.
+	 * @return {@code this}
+	 * @since 4.2
+	 */
+	public ObjectChecker setSkipList(@Nullable ObjectIdSet objects) {
+		skipList = objects;
+		return this;
+	}
+
+	/**
+	 * Configure error types to be ignored across all objects.
+	 *
+	 * @param ids
+	 *            error types to ignore. The caller's set is copied.
+	 * @return {@code this}
+	 * @since 4.2
+	 */
+	public ObjectChecker setIgnore(@Nullable Set<ErrorType> ids) {
+		errors = EnumSet.allOf(ErrorType.class);
+		if (ids != null) {
+			errors.removeAll(ids);
+		}
+		return this;
+	}
+
+	/**
+	 * Add message type to be ignored across all objects.
+	 *
+	 * @param id
+	 *            error type to ignore.
+	 * @param ignore
+	 *            true to ignore this error; false to treat the error as an
+	 *            error and throw.
+	 * @return {@code this}
+	 * @since 4.2
+	 */
+	public ObjectChecker setIgnore(ErrorType id, boolean ignore) {
+		if (ignore) {
+			errors.remove(id);
+		} else {
+			errors.add(id);
+		}
+		return this;
+	}
+
+	/**
 	 * Enable accepting leading zero mode in tree entries.
 	 * <p>
 	 * Some broken Git libraries generated leading zeros in the mode part of
 	 * tree entries. This is technically incorrect but gracefully allowed by
 	 * git-core. JGit rejects such trees by default, but may need to accept
 	 * them on broken histories.
+	 * <p>
+	 * Same as {@code setIgnore(ZERO_PADDED_FILEMODE, allow)}.
 	 *
 	 * @param allow allow leading zero mode.
 	 * @return {@code this}.
 	 * @since 3.4
 	 */
 	public ObjectChecker setAllowLeadingZeroFileMode(boolean allow) {
-		allowZeroMode = allow;
-		return this;
+		return setIgnore(ZERO_PADDED_FILEMODE, allow);
 	}
 
 	/**
@@ -183,62 +323,117 @@ public class ObjectChecker {
 	 * @throws CorruptObjectException
 	 *             if an error is identified.
 	 */
-	public void check(final int objType, final byte[] raw)
+	public void check(int objType, byte[] raw)
+			throws CorruptObjectException {
+		check(idFor(objType, raw), objType, raw);
+	}
+
+	/**
+	 * Check an object for parsing errors.
+	 *
+	 * @param id
+	 *            identify of the object being checked.
+	 * @param objType
+	 *            type of the object. Must be a valid object type code in
+	 *            {@link Constants}.
+	 * @param raw
+	 *            the raw data which comprises the object. This should be in the
+	 *            canonical format (that is the format used to generate the
+	 *            ObjectId of the object). The array is never modified.
+	 * @throws CorruptObjectException
+	 *             if an error is identified.
+	 * @since 4.2
+	 */
+	public void check(@Nullable AnyObjectId id, int objType, byte[] raw)
 			throws CorruptObjectException {
 		switch (objType) {
-		case Constants.OBJ_COMMIT:
-			checkCommit(raw);
+		case OBJ_COMMIT:
+			checkCommit(id, raw);
 			break;
-		case Constants.OBJ_TAG:
-			checkTag(raw);
+		case OBJ_TAG:
+			checkTag(id, raw);
 			break;
-		case Constants.OBJ_TREE:
-			checkTree(raw);
+		case OBJ_TREE:
+			checkTree(id, raw);
 			break;
-		case Constants.OBJ_BLOB:
+		case OBJ_BLOB:
 			checkBlob(raw);
 			break;
 		default:
-			throw new CorruptObjectException(MessageFormat.format(
+			report(UNKNOWN_TYPE, id, MessageFormat.format(
 					JGitText.get().corruptObjectInvalidType2,
 					Integer.valueOf(objType)));
 		}
 	}
 
-	private int id(final byte[] raw, final int ptr) {
+	private boolean checkId(byte[] raw) {
+		int p = bufPtr.value;
 		try {
-			tempId.fromString(raw, ptr);
-			return ptr + Constants.OBJECT_ID_STRING_LENGTH;
+			tempId.fromString(raw, p);
 		} catch (IllegalArgumentException e) {
-			return -1;
+			bufPtr.value = nextLF(raw, p);
+			return false;
+		}
+
+		p += OBJECT_ID_STRING_LENGTH;
+		if (raw[p] == '\n') {
+			bufPtr.value = p + 1;
+			return true;
 		}
+		bufPtr.value = nextLF(raw, p);
+		return false;
 	}
 
-	private int personIdent(final byte[] raw, int ptr) {
-		if (allowInvalidPersonIdent)
-			return nextLF(raw, ptr) - 1;
+	private void checkPersonIdent(byte[] raw, @Nullable AnyObjectId id)
+			throws CorruptObjectException {
+		if (allowInvalidPersonIdent) {
+			bufPtr.value = nextLF(raw, bufPtr.value);
+			return;
+		}
 
-		final int emailB = nextLF(raw, ptr, '<');
-		if (emailB == ptr || raw[emailB - 1] != '<')
-			return -1;
+		final int emailB = nextLF(raw, bufPtr.value, '<');
+		if (emailB == bufPtr.value || raw[emailB - 1] != '<') {
+			report(MISSING_EMAIL, id, JGitText.get().corruptObjectMissingEmail);
+			bufPtr.value = nextLF(raw, bufPtr.value);
+			return;
+		}
 
 		final int emailE = nextLF(raw, emailB, '>');
-		if (emailE == emailB || raw[emailE - 1] != '>')
-			return -1;
-		if (emailE == raw.length || raw[emailE] != ' ')
-			return -1;
+		if (emailE == emailB || raw[emailE - 1] != '>') {
+			report(BAD_EMAIL, id, JGitText.get().corruptObjectBadEmail);
+			bufPtr.value = nextLF(raw, bufPtr.value);
+			return;
+		}
+		if (emailE == raw.length || raw[emailE] != ' ') {
+			report(MISSING_SPACE_BEFORE_DATE, id,
+					JGitText.get().corruptObjectBadDate);
+			bufPtr.value = nextLF(raw, bufPtr.value);
+			return;
+		}
 
-		parseBase10(raw, emailE + 1, ptrout); // when
-		ptr = ptrout.value;
-		if (emailE + 1 == ptr)
-			return -1;
-		if (ptr == raw.length || raw[ptr] != ' ')
-			return -1;
+		parseBase10(raw, emailE + 1, bufPtr); // when
+		if (emailE + 1 == bufPtr.value || bufPtr.value == raw.length
+				|| raw[bufPtr.value] != ' ') {
+			report(BAD_DATE, id, JGitText.get().corruptObjectBadDate);
+			bufPtr.value = nextLF(raw, bufPtr.value);
+			return;
+		}
+
+		int p = bufPtr.value + 1;
+		parseBase10(raw, p, bufPtr); // tz offset
+		if (p == bufPtr.value) {
+			report(BAD_TIMEZONE, id, JGitText.get().corruptObjectBadTimezone);
+			bufPtr.value = nextLF(raw, bufPtr.value);
+			return;
+		}
 
-		parseBase10(raw, ptr + 1, ptrout); // tz offset
-		if (ptr + 1 == ptrout.value)
-			return -1;
-		return ptrout.value;
+		p = bufPtr.value;
+		if (raw[p] == '\n') {
+			bufPtr.value = p + 1;
+		} else {
+			report(BAD_TIMEZONE, id, JGitText.get().corruptObjectBadTimezone);
+			bufPtr.value = nextLF(raw, p);
+		}
 	}
 
 	/**
@@ -249,36 +444,50 @@ public class ObjectChecker {
 	 * @throws CorruptObjectException
 	 *             if any error was detected.
 	 */
-	public void checkCommit(final byte[] raw) throws CorruptObjectException {
-		int ptr = 0;
+	public void checkCommit(byte[] raw) throws CorruptObjectException {
+		checkCommit(idFor(OBJ_COMMIT, raw), raw);
+	}
 
-		if ((ptr = match(raw, ptr, tree)) < 0)
-			throw new CorruptObjectException(
-					JGitText.get().corruptObjectNotreeHeader);
-		if ((ptr = id(raw, ptr)) < 0 || raw[ptr++] != '\n')
-			throw new CorruptObjectException(
-					JGitText.get().corruptObjectInvalidTree);
+	/**
+	 * Check a commit for errors.
+	 *
+	 * @param id
+	 *            identity of the object being checked.
+	 * @param raw
+	 *            the commit data. The array is never modified.
+	 * @throws CorruptObjectException
+	 *             if any error was detected.
+	 * @since 4.2
+	 */
+	public void checkCommit(@Nullable AnyObjectId id, byte[] raw)
+			throws CorruptObjectException {
+		bufPtr.value = 0;
 
-		while (match(raw, ptr, parent) >= 0) {
-			ptr += parent.length;
-			if ((ptr = id(raw, ptr)) < 0 || raw[ptr++] != '\n')
-				throw new CorruptObjectException(
+		if (!match(raw, tree)) {
+			report(MISSING_TREE, id, JGitText.get().corruptObjectNotreeHeader);
+		} else if (!checkId(raw)) {
+			report(BAD_TREE_SHA1, id, JGitText.get().corruptObjectInvalidTree);
+		}
+
+		while (match(raw, parent)) {
+			if (!checkId(raw)) {
+				report(BAD_PARENT_SHA1, id,
 						JGitText.get().corruptObjectInvalidParent);
+			}
 		}
 
-		if ((ptr = match(raw, ptr, author)) < 0)
-			throw new CorruptObjectException(
-					JGitText.get().corruptObjectNoAuthor);
-		if ((ptr = personIdent(raw, ptr)) < 0 || raw[ptr++] != '\n')
-			throw new CorruptObjectException(
-					JGitText.get().corruptObjectInvalidAuthor);
+		if (match(raw, author)) {
+			checkPersonIdent(raw, id);
+		} else {
+			report(MISSING_AUTHOR, id, JGitText.get().corruptObjectNoAuthor);
+		}
 
-		if ((ptr = match(raw, ptr, committer)) < 0)
-			throw new CorruptObjectException(
+		if (match(raw, committer)) {
+			checkPersonIdent(raw, id);
+		} else {
+			report(MISSING_COMMITTER, id,
 					JGitText.get().corruptObjectNoCommitter);
-		if ((ptr = personIdent(raw, ptr)) < 0 || raw[ptr++] != '\n')
-			throw new CorruptObjectException(
-					JGitText.get().corruptObjectInvalidCommitter);
+		}
 	}
 
 	/**
@@ -289,30 +498,46 @@ public class ObjectChecker {
 	 * @throws CorruptObjectException
 	 *             if any error was detected.
 	 */
-	public void checkTag(final byte[] raw) throws CorruptObjectException {
-		int ptr = 0;
+	public void checkTag(byte[] raw) throws CorruptObjectException {
+		checkTag(idFor(OBJ_TAG, raw), raw);
+	}
 
-		if ((ptr = match(raw, ptr, object)) < 0)
-			throw new CorruptObjectException(
+	/**
+	 * Check an annotated tag for errors.
+	 *
+	 * @param id
+	 *            identity of the object being checked.
+	 * @param raw
+	 *            the tag data. The array is never modified.
+	 * @throws CorruptObjectException
+	 *             if any error was detected.
+	 * @since 4.2
+	 */
+	public void checkTag(@Nullable AnyObjectId id, byte[] raw)
+			throws CorruptObjectException {
+		bufPtr.value = 0;
+		if (!match(raw, object)) {
+			report(MISSING_OBJECT, id,
 					JGitText.get().corruptObjectNoObjectHeader);
-		if ((ptr = id(raw, ptr)) < 0 || raw[ptr++] != '\n')
-			throw new CorruptObjectException(
+		} else if (!checkId(raw)) {
+			report(BAD_OBJECT_SHA1, id,
 					JGitText.get().corruptObjectInvalidObject);
+		}
 
-		if ((ptr = match(raw, ptr, type)) < 0)
-			throw new CorruptObjectException(
+		if (!match(raw, type)) {
+			report(MISSING_TYPE_ENTRY, id,
 					JGitText.get().corruptObjectNoTypeHeader);
-		ptr = nextLF(raw, ptr);
+		}
+		bufPtr.value = nextLF(raw, bufPtr.value);
 
-		if ((ptr = match(raw, ptr, tag)) < 0)
-			throw new CorruptObjectException(
+		if (!match(raw, tag)) {
+			report(MISSING_TAG_ENTRY, id,
 					JGitText.get().corruptObjectNoTagHeader);
-		ptr = nextLF(raw, ptr);
+		}
+		bufPtr.value = nextLF(raw, bufPtr.value);
 
-		if ((ptr = match(raw, ptr, tagger)) > 0) {
-			if ((ptr = personIdent(raw, ptr)) < 0 || raw[ptr++] != '\n')
-				throw new CorruptObjectException(
-						JGitText.get().corruptObjectInvalidTagger);
+		if (match(raw, tagger)) {
+			checkPersonIdent(raw, id);
 		}
 	}
 
@@ -381,7 +606,23 @@ public class ObjectChecker {
 	 * @throws CorruptObjectException
 	 *             if any error was detected.
 	 */
-	public void checkTree(final byte[] raw) throws CorruptObjectException {
+	public void checkTree(byte[] raw) throws CorruptObjectException {
+		checkTree(idFor(OBJ_TREE, raw), raw);
+	}
+
+	/**
+	 * Check a canonical formatted tree for errors.
+	 *
+	 * @param id
+	 *            identity of the object being checked.
+	 * @param raw
+	 *            the raw tree data. The array is never modified.
+	 * @throws CorruptObjectException
+	 *             if any error was detected.
+	 * @since 4.2
+	 */
+	public void checkTree(@Nullable AnyObjectId id, byte[] raw)
+			throws CorruptObjectException {
 		final int sz = raw.length;
 		int ptr = 0;
 		int lastNameB = 0, lastNameE = 0, lastMode = 0;
@@ -392,74 +633,89 @@ public class ObjectChecker {
 		while (ptr < sz) {
 			int thisMode = 0;
 			for (;;) {
-				if (ptr == sz)
+				if (ptr == sz) {
 					throw new CorruptObjectException(
 							JGitText.get().corruptObjectTruncatedInMode);
+				}
 				final byte c = raw[ptr++];
 				if (' ' == c)
 					break;
-				if (c < '0' || c > '7')
+				if (c < '0' || c > '7') {
 					throw new CorruptObjectException(
 							JGitText.get().corruptObjectInvalidModeChar);
-				if (thisMode == 0 && c == '0' && !allowZeroMode)
-					throw new CorruptObjectException(
+				}
+				if (thisMode == 0 && c == '0') {
+					report(ZERO_PADDED_FILEMODE, id,
 							JGitText.get().corruptObjectInvalidModeStartsZero);
+				}
 				thisMode <<= 3;
 				thisMode += c - '0';
 			}
 
-			if (FileMode.fromBits(thisMode).getObjectType() == Constants.OBJ_BAD)
+			if (FileMode.fromBits(thisMode).getObjectType() == OBJ_BAD) {
 				throw new CorruptObjectException(MessageFormat.format(
 						JGitText.get().corruptObjectInvalidMode2,
 						Integer.valueOf(thisMode)));
+			}
 
 			final int thisNameB = ptr;
-			ptr = scanPathSegment(raw, ptr, sz);
-			if (ptr == sz || raw[ptr] != 0)
+			ptr = scanPathSegment(raw, ptr, sz, id);
+			if (ptr == sz || raw[ptr] != 0) {
 				throw new CorruptObjectException(
 						JGitText.get().corruptObjectTruncatedInName);
-			checkPathSegment2(raw, thisNameB, ptr);
+			}
+			checkPathSegment2(raw, thisNameB, ptr, id);
 			if (normalized != null) {
-				if (!normalized.add(normalize(raw, thisNameB, ptr)))
-					throw new CorruptObjectException(
+				if (!normalized.add(normalize(raw, thisNameB, ptr))) {
+					report(DUPLICATE_ENTRIES, id,
 							JGitText.get().corruptObjectDuplicateEntryNames);
-			} else if (duplicateName(raw, thisNameB, ptr))
-				throw new CorruptObjectException(
+				}
+			} else if (duplicateName(raw, thisNameB, ptr)) {
+				report(DUPLICATE_ENTRIES, id,
 						JGitText.get().corruptObjectDuplicateEntryNames);
+			}
 
 			if (lastNameB != 0) {
 				final int cmp = pathCompare(raw, lastNameB, lastNameE,
 						lastMode, thisNameB, ptr, thisMode);
-				if (cmp > 0)
-					throw new CorruptObjectException(
+				if (cmp > 0) {
+					report(TREE_NOT_SORTED, id,
 							JGitText.get().corruptObjectIncorrectSorting);
+				}
 			}
 
 			lastNameB = thisNameB;
 			lastNameE = ptr;
 			lastMode = thisMode;
 
-			ptr += 1 + Constants.OBJECT_ID_LENGTH;
-			if (ptr > sz)
+			ptr += 1 + OBJECT_ID_LENGTH;
+			if (ptr > sz) {
 				throw new CorruptObjectException(
 						JGitText.get().corruptObjectTruncatedInObjectId);
+			}
+			if (ObjectId.zeroId().compareTo(raw, ptr - OBJECT_ID_LENGTH) == 0) {
+				report(NULL_SHA1, id, JGitText.get().corruptObjectZeroId);
+			}
 		}
 	}
 
-	private int scanPathSegment(byte[] raw, int ptr, int end)
-			throws CorruptObjectException {
+	private int scanPathSegment(byte[] raw, int ptr, int end,
+			@Nullable AnyObjectId id) throws CorruptObjectException {
 		for (; ptr < end; ptr++) {
 			byte c = raw[ptr];
-			if (c == 0)
+			if (c == 0) {
 				return ptr;
-			if (c == '/')
-				throw new CorruptObjectException(
+			}
+			if (c == '/') {
+				report(FULL_PATHNAME, id,
 						JGitText.get().corruptObjectNameContainsSlash);
+			}
 			if (windows && isInvalidOnWindows(c)) {
-				if (c > 31)
+				if (c > 31) {
 					throw new CorruptObjectException(String.format(
 							JGitText.get().corruptObjectNameContainsChar,
 							Byte.valueOf(c)));
+				}
 				throw new CorruptObjectException(String.format(
 						JGitText.get().corruptObjectNameContainsByte,
 						Integer.valueOf(c & 0xff)));
@@ -468,6 +724,26 @@ public class ObjectChecker {
 		return ptr;
 	}
 
+	@SuppressWarnings("resource")
+	@Nullable
+	private ObjectId idFor(int objType, byte[] raw) {
+		if (skipList != null) {
+			return new ObjectInserter.Formatter().idFor(objType, raw);
+		}
+		return null;
+	}
+
+	private void report(@NonNull ErrorType err, @Nullable AnyObjectId id,
+			String why) throws CorruptObjectException {
+		if (errors.contains(err)
+				&& (id == null || skipList == null || !skipList.contains(id))) {
+			if (id != null) {
+				throw new CorruptObjectException(err, id, why);
+			}
+			throw new CorruptObjectException(why);
+		}
+	}
+
 	/**
 	 * Check tree path entry for validity.
 	 * <p>
@@ -518,73 +794,82 @@ public class ObjectChecker {
 	 */
 	public void checkPathSegment(byte[] raw, int ptr, int end)
 			throws CorruptObjectException {
-		int e = scanPathSegment(raw, ptr, end);
+		int e = scanPathSegment(raw, ptr, end, null);
 		if (e < end && raw[e] == 0)
 			throw new CorruptObjectException(
 					JGitText.get().corruptObjectNameContainsNullByte);
-		checkPathSegment2(raw, ptr, end);
+		checkPathSegment2(raw, ptr, end, null);
 	}
 
-	private void checkPathSegment2(byte[] raw, int ptr, int end)
-			throws CorruptObjectException {
-		if (ptr == end)
-			throw new CorruptObjectException(
-					JGitText.get().corruptObjectNameZeroLength);
+	private void checkPathSegment2(byte[] raw, int ptr, int end,
+			@Nullable AnyObjectId id) throws CorruptObjectException {
+		if (ptr == end) {
+			report(EMPTY_NAME, id, JGitText.get().corruptObjectNameZeroLength);
+			return;
+		}
+
 		if (raw[ptr] == '.') {
 			switch (end - ptr) {
 			case 1:
-				throw new CorruptObjectException(
-						JGitText.get().corruptObjectNameDot);
+				report(HAS_DOT, id, JGitText.get().corruptObjectNameDot);
+				break;
 			case 2:
-				if (raw[ptr + 1] == '.')
-					throw new CorruptObjectException(
+				if (raw[ptr + 1] == '.') {
+					report(HAS_DOTDOT, id,
 							JGitText.get().corruptObjectNameDotDot);
+				}
 				break;
 			case 4:
-				if (isGit(raw, ptr + 1))
-					throw new CorruptObjectException(String.format(
+				if (isGit(raw, ptr + 1)) {
+					report(HAS_DOTGIT, id, String.format(
 							JGitText.get().corruptObjectInvalidName,
 							RawParseUtils.decode(raw, ptr, end)));
+				}
 				break;
 			default:
-				if (end - ptr > 4 && isNormalizedGit(raw, ptr + 1, end))
-					throw new CorruptObjectException(String.format(
+				if (end - ptr > 4 && isNormalizedGit(raw, ptr + 1, end)) {
+					report(HAS_DOTGIT, id, String.format(
 							JGitText.get().corruptObjectInvalidName,
 							RawParseUtils.decode(raw, ptr, end)));
+				}
 			}
 		} else if (isGitTilde1(raw, ptr, end)) {
-			throw new CorruptObjectException(String.format(
+			report(HAS_DOTGIT, id, String.format(
 					JGitText.get().corruptObjectInvalidName,
 					RawParseUtils.decode(raw, ptr, end)));
 		}
-
-		if (macosx && isMacHFSGit(raw, ptr, end))
-			throw new CorruptObjectException(String.format(
+		if (macosx && isMacHFSGit(raw, ptr, end, id)) {
+			report(HAS_DOTGIT, id, String.format(
 					JGitText.get().corruptObjectInvalidNameIgnorableUnicode,
 					RawParseUtils.decode(raw, ptr, end)));
+		}
 
 		if (windows) {
 			// Windows ignores space and dot at end of file name.
-			if (raw[end - 1] == ' ' || raw[end - 1] == '.')
-				throw new CorruptObjectException(String.format(
+			if (raw[end - 1] == ' ' || raw[end - 1] == '.') {
+				report(WIN32_BAD_NAME, id, String.format(
 						JGitText.get().corruptObjectInvalidNameEnd,
 						Character.valueOf(((char) raw[end - 1]))));
-			if (end - ptr >= 3)
-				checkNotWindowsDevice(raw, ptr, end);
+			}
+			if (end - ptr >= 3) {
+				checkNotWindowsDevice(raw, ptr, end, id);
+			}
 		}
 	}
 
 	// Mac's HFS+ folds permutations of ".git" and Unicode ignorable characters
 	// to ".git" therefore we should prevent such names
-	private static boolean isMacHFSGit(byte[] raw, int ptr, int end)
-			throws CorruptObjectException {
+	private boolean isMacHFSGit(byte[] raw, int ptr, int end,
+			@Nullable AnyObjectId id) throws CorruptObjectException {
 		boolean ignorable = false;
 		byte[] git = new byte[] { '.', 'g', 'i', 't' };
 		int g = 0;
 		while (ptr < end) {
 			switch (raw[ptr]) {
 			case (byte) 0xe2: // http://www.utf8-chartable.de/unicode-utf8-table.pl?start=8192
-				checkTruncatedIgnorableUTF8(raw, ptr, end);
+				if (!checkTruncatedIgnorableUTF8(raw, ptr, end, id)) {
+					return false;
+				}
 				switch (raw[ptr + 1]) {
 				case (byte) 0x80:
 					switch (raw[ptr + 2]) {
@@ -621,7 +906,9 @@ public class ObjectChecker {
 					return false;
 				}
 			case (byte) 0xef: // http://www.utf8-chartable.de/unicode-utf8-table.pl?start=65024
-				checkTruncatedIgnorableUTF8(raw, ptr, end);
+				if (!checkTruncatedIgnorableUTF8(raw, ptr, end, id)) {
+					return false;
+				}
 				// U+FEFF 0xefbbbf ZERO WIDTH NO-BREAK SPACE
 				if ((raw[ptr + 1] == (byte) 0xbb)
 						&& (raw[ptr + 2] == (byte) 0xbf)) {
@@ -642,12 +929,15 @@ public class ObjectChecker {
 		return false;
 	}
 
-	private static void checkTruncatedIgnorableUTF8(byte[] raw, int ptr, int end)
-			throws CorruptObjectException {
-		if ((ptr + 2) >= end)
-			throw new CorruptObjectException(MessageFormat.format(
+	private boolean checkTruncatedIgnorableUTF8(byte[] raw, int ptr, int end,
+			@Nullable AnyObjectId id) throws CorruptObjectException {
+		if ((ptr + 2) >= end) {
+			report(BAD_UTF8, id, MessageFormat.format(
 					JGitText.get().corruptObjectInvalidNameInvalidUtf8,
 					toHexString(raw, ptr, end)));
+			return false;
+		}
+		return true;
 	}
 
 	private static String toHexString(byte[] raw, int ptr, int end) {
@@ -657,33 +947,36 @@ public class ObjectChecker {
 		return b.toString();
 	}
 
-	private static void checkNotWindowsDevice(byte[] raw, int ptr, int end)
-			throws CorruptObjectException {
+	private void checkNotWindowsDevice(byte[] raw, int ptr, int end,
+			@Nullable AnyObjectId id) throws CorruptObjectException {
 		switch (toLower(raw[ptr])) {
 		case 'a': // AUX
 			if (end - ptr >= 3
 					&& toLower(raw[ptr + 1]) == 'u'
 					&& toLower(raw[ptr + 2]) == 'x'
-					&& (end - ptr == 3 || raw[ptr + 3] == '.'))
-				throw new CorruptObjectException(
+					&& (end - ptr == 3 || raw[ptr + 3] == '.')) {
+				report(WIN32_BAD_NAME, id,
 						JGitText.get().corruptObjectInvalidNameAux);
+			}
 			break;
 
 		case 'c': // CON, COM[1-9]
 			if (end - ptr >= 3
 					&& toLower(raw[ptr + 2]) == 'n'
 					&& toLower(raw[ptr + 1]) == 'o'
-					&& (end - ptr == 3 || raw[ptr + 3] == '.'))
-				throw new CorruptObjectException(
+					&& (end - ptr == 3 || raw[ptr + 3] == '.')) {
+				report(WIN32_BAD_NAME, id,
 						JGitText.get().corruptObjectInvalidNameCon);
+			}
 			if (end - ptr >= 4
 					&& toLower(raw[ptr + 2]) == 'm'
 					&& toLower(raw[ptr + 1]) == 'o'
 					&& isPositiveDigit(raw[ptr + 3])
-					&& (end - ptr == 4 || raw[ptr + 4] == '.'))
-				throw new CorruptObjectException(String.format(
+					&& (end - ptr == 4 || raw[ptr + 4] == '.')) {
+				report(WIN32_BAD_NAME, id, String.format(
 						JGitText.get().corruptObjectInvalidNameCom,
 						Character.valueOf(((char) raw[ptr + 3]))));
+			}
 			break;
 
 		case 'l': // LPT[1-9]
@@ -691,28 +984,31 @@ public class ObjectChecker {
 					&& toLower(raw[ptr + 1]) == 'p'
 					&& toLower(raw[ptr + 2]) == 't'
 					&& isPositiveDigit(raw[ptr + 3])
-					&& (end - ptr == 4 || raw[ptr + 4] == '.'))
-				throw new CorruptObjectException(String.format(
+					&& (end - ptr == 4 || raw[ptr + 4] == '.')) {
+				report(WIN32_BAD_NAME, id, String.format(
 						JGitText.get().corruptObjectInvalidNameLpt,
 						Character.valueOf(((char) raw[ptr + 3]))));
+			}
 			break;
 
 		case 'n': // NUL
 			if (end - ptr >= 3
 					&& toLower(raw[ptr + 1]) == 'u'
 					&& toLower(raw[ptr + 2]) == 'l'
-					&& (end - ptr == 3 || raw[ptr + 3] == '.'))
-				throw new CorruptObjectException(
+					&& (end - ptr == 3 || raw[ptr + 3] == '.')) {
+				report(WIN32_BAD_NAME, id,
 						JGitText.get().corruptObjectInvalidNameNul);
+			}
 			break;
 
 		case 'p': // PRN
 			if (end - ptr >= 3
 					&& toLower(raw[ptr + 1]) == 'r'
 					&& toLower(raw[ptr + 2]) == 'n'
-					&& (end - ptr == 3 || raw[ptr + 3] == '.'))
-				throw new CorruptObjectException(
+					&& (end - ptr == 3 || raw[ptr + 3] == '.')) {
+				report(WIN32_BAD_NAME, id,
 						JGitText.get().corruptObjectInvalidNamePrn);
+			}
 			break;
 		}
 	}
@@ -765,6 +1061,15 @@ public class ObjectChecker {
 		return false;
 	}
 
+	private boolean match(byte[] b, byte[] src) {
+		int r = RawParseUtils.match(b, bufPtr.value, src);
+		if (r < 0) {
+			return false;
+		}
+		bufPtr.value = r;
+		return true;
+	}
+
 	private static char toLower(byte b) {
 		if ('A' <= b && b <= 'Z')
 			return (char) (b + ('a' - 'A'));
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/PackParser.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/PackParser.java
index 6e5fc9f009..b96fe885e1 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/PackParser.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/PackParser.java
@@ -1049,8 +1049,11 @@ public abstract class PackParser {
 			final byte[] data) throws IOException {
 		if (objCheck != null) {
 			try {
-				objCheck.check(type, data);
+				objCheck.check(id, type, data);
 			} catch (CorruptObjectException e) {
+				if (e.getErrorType() != null) {
+					throw e;
+				}
 				throw new CorruptObjectException(MessageFormat.format(
 						JGitText.get().invalidObject,
 						Constants.typeString(type),
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/TransferConfig.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/TransferConfig.java
index f9b74c84e5..72c9c8b93e 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/TransferConfig.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/TransferConfig.java
@@ -43,13 +43,20 @@
 
 package org.eclipse.jgit.transport;
 
+import static org.eclipse.jgit.util.StringUtils.equalsIgnoreCase;
+import static org.eclipse.jgit.util.StringUtils.toLowerCase;
+
+import java.io.File;
+import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.Map;
 
 import org.eclipse.jgit.annotations.Nullable;
+import org.eclipse.jgit.internal.storage.file.LazyObjectIdSetFile;
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.Config.SectionParser;
 import org.eclipse.jgit.lib.ObjectChecker;
+import org.eclipse.jgit.lib.ObjectIdSet;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.util.SystemReader;
@@ -59,6 +66,8 @@ import org.eclipse.jgit.util.SystemReader;
  * parameters.
  */
 public class TransferConfig {
+	private static final String FSCK = "fsck"; //$NON-NLS-1$
+
 	/** Key for {@link Config#get(SectionParser)}. */
 	public static final Config.SectionParser<TransferConfig> KEY = new SectionParser<TransferConfig>() {
 		public TransferConfig parse(final Config cfg) {
@@ -66,9 +75,14 @@ public class TransferConfig {
 		}
 	};
 
+	enum FsckMode {
+		ERROR, WARN, IGNORE;
+	}
+
 	private final boolean fetchFsck;
 	private final boolean receiveFsck;
-	private final boolean allowLeadingZeroFileMode;
+	private final String fsckSkipList;
+	private final EnumSet<ObjectChecker.ErrorType> ignore;
 	private final boolean allowInvalidPersonIdent;
 	private final boolean safeForWindows;
 	private final boolean safeForMacOS;
@@ -84,13 +98,44 @@ public class TransferConfig {
 		boolean fsck = rc.getBoolean("transfer", "fsckobjects", false); //$NON-NLS-1$ //$NON-NLS-2$
 		fetchFsck = rc.getBoolean("fetch", "fsckobjects", fsck); //$NON-NLS-1$ //$NON-NLS-2$
 		receiveFsck = rc.getBoolean("receive", "fsckobjects", fsck); //$NON-NLS-1$ //$NON-NLS-2$
-		allowLeadingZeroFileMode = rc.getBoolean("fsck", "allowLeadingZeroFileMode", false); //$NON-NLS-1$ //$NON-NLS-2$
-		allowInvalidPersonIdent = rc.getBoolean("fsck", "allowInvalidPersonIdent", false); //$NON-NLS-1$ //$NON-NLS-2$
-		safeForWindows = rc.getBoolean("fsck", "safeForWindows", //$NON-NLS-1$ //$NON-NLS-2$
+		fsckSkipList = rc.getString(FSCK, null, "skipList"); //$NON-NLS-1$
+		allowInvalidPersonIdent = rc.getBoolean(FSCK, "allowInvalidPersonIdent", false); //$NON-NLS-1$
+		safeForWindows = rc.getBoolean(FSCK, "safeForWindows", //$NON-NLS-1$
 						SystemReader.getInstance().isWindows());
-		safeForMacOS = rc.getBoolean("fsck", "safeForMacOS", //$NON-NLS-1$ //$NON-NLS-2$
+		safeForMacOS = rc.getBoolean(FSCK, "safeForMacOS", //$NON-NLS-1$
 						SystemReader.getInstance().isMacOS());
 
+		ignore = EnumSet.noneOf(ObjectChecker.ErrorType.class);
+		EnumSet<ObjectChecker.ErrorType> set = EnumSet
+				.noneOf(ObjectChecker.ErrorType.class);
+		for (String key : rc.getNames(FSCK)) {
+			if (equalsIgnoreCase(key, "skipList") //$NON-NLS-1$
+					|| equalsIgnoreCase(key, "allowLeadingZeroFileMode") //$NON-NLS-1$
+					|| equalsIgnoreCase(key, "allowInvalidPersonIdent") //$NON-NLS-1$
+					|| equalsIgnoreCase(key, "safeForWindows") //$NON-NLS-1$
+					|| equalsIgnoreCase(key, "safeForMacOS")) { //$NON-NLS-1$
+				continue;
+			}
+
+			ObjectChecker.ErrorType id = FsckKeyNameHolder.parse(key);
+			if (id != null) {
+				switch (rc.getEnum(FSCK, null, key, FsckMode.ERROR)) {
+				case ERROR:
+					ignore.remove(id);
+					break;
+				case WARN:
+				case IGNORE:
+					ignore.add(id);
+					break;
+				}
+				set.add(id);
+			}
+		}
+		if (!set.contains(ObjectChecker.ErrorType.ZERO_PADDED_FILEMODE)
+				&& rc.getBoolean(FSCK, "allowLeadingZeroFileMode", false)) { //$NON-NLS-1$
+			ignore.add(ObjectChecker.ErrorType.ZERO_PADDED_FILEMODE);
+		}
+
 		allowTipSha1InWant = rc.getBoolean(
 				"uploadpack", "allowtipsha1inwant", false); //$NON-NLS-1$ //$NON-NLS-2$
 		allowReachableSha1InWant = rc.getBoolean(
@@ -123,10 +168,18 @@ public class TransferConfig {
 			return null;
 		}
 		return new ObjectChecker()
-			.setAllowLeadingZeroFileMode(allowLeadingZeroFileMode)
+			.setIgnore(ignore)
 			.setAllowInvalidPersonIdent(allowInvalidPersonIdent)
 			.setSafeForWindows(safeForWindows)
-			.setSafeForMacOS(safeForMacOS);
+			.setSafeForMacOS(safeForMacOS)
+			.setSkipList(skipList());
+	}
+
+	private ObjectIdSet skipList() {
+		if (fsckSkipList != null && !fsckSkipList.isEmpty()) {
+			return new LazyObjectIdSetFile(new File(fsckSkipList));
+		}
+		return null;
 	}
 
 	/**
@@ -175,4 +228,34 @@ public class TransferConfig {
 			}
 		};
 	}
+
+	static class FsckKeyNameHolder {
+		private static final Map<String, ObjectChecker.ErrorType> errors;
+
+		static {
+			errors = new HashMap<>();
+			for (ObjectChecker.ErrorType m : ObjectChecker.ErrorType.values()) {
+				errors.put(keyNameFor(m.name()), m);
+			}
+		}
+
+		@Nullable
+		static ObjectChecker.ErrorType parse(String key) {
+			return errors.get(toLowerCase(key));
+		}
+
+		private static String keyNameFor(String name) {
+			StringBuilder r = new StringBuilder(name.length());
+			for (int i = 0; i < name.length(); i++) {
+				char c = name.charAt(i);
+				if (c != '_') {
+					r.append(c);
+				}
+			}
+			return toLowerCase(r.toString());
+		}
+
+		private FsckKeyNameHolder() {
+		}
+	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/WalkFetchConnection.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/WalkFetchConnection.java
index dfc3ee4c30..17edfdc4fb 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/WalkFetchConnection.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/WalkFetchConnection.java
@@ -637,10 +637,11 @@ class WalkFetchConnection extends BaseFetchConnection {
 		final byte[] raw = uol.getCachedBytes();
 		if (objCheck != null) {
 			try {
-				objCheck.check(type, raw);
+				objCheck.check(id, type, raw);
 			} catch (CorruptObjectException e) {
-				throw new TransportException(MessageFormat.format(JGitText.get().transportExceptionInvalid
-						, Constants.typeString(type), id.name(), e.getMessage()));
+				throw new TransportException(MessageFormat.format(
+						JGitText.get().transportExceptionInvalid,
+						Constants.typeString(type), id.name(), e.getMessage()));
 			}
 		}