Merge branch 'master' into stable-6.8

* master:
  Adapt to type parameter added in commons-compress 1.25.0
  Improve footer parsing to allow multiline footers.
  Make the tests buildable by bazel test
  BitmapIndex: Add interface to track bitmaps found (or not)
  BitmapWalker: Remove BitmapWalkListener

Change-Id: Id2aeb0acd37bdd68a2f2c9f09f4d442fa40c9dd1

13 files changed, 272 insertions, 143 deletions

diff --git a/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/BaseFormat.java b/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/BaseFormat.java
index 25cd36817a..4757998a29 100644
--- a/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/BaseFormat.java
+++ b/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/BaseFormat.java
@@ -15,6 +15,7 @@ import java.io.IOException;
 import java.text.MessageFormat;
 import java.util.Map;
 
+import org.apache.commons.compress.archivers.ArchiveEntry;
 import org.apache.commons.compress.archivers.ArchiveOutputStream;
 import org.eclipse.jgit.archive.internal.ArchiveText;
 import org.eclipse.jgit.util.StringUtils;
@@ -42,7 +43,8 @@ public class BaseFormat {
 	 * @throws IOException
 	 *             if an IO error occurred
 	 */
-	protected ArchiveOutputStream applyFormatOptions(ArchiveOutputStream s,
+	protected ArchiveOutputStream<? extends ArchiveEntry> applyFormatOptions(
+			ArchiveOutputStream<? extends ArchiveEntry> s,
 			Map<String, Object> o) throws IOException {
 		for (Map.Entry<String, Object> p : o.entrySet()) {
 			try {
diff --git a/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TarFormat.java b/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TarFormat.java
index dfa60321b0..3db1124752 100644
--- a/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TarFormat.java
+++ b/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TarFormat.java
@@ -35,7 +35,7 @@ import org.eclipse.jgit.revwalk.RevCommit;
  * Unix TAR format (ustar + some PAX extensions).
  */
 public final class TarFormat extends BaseFormat implements
-		ArchiveCommand.Format<ArchiveOutputStream> {
+		ArchiveCommand.Format<ArchiveOutputStream<TarArchiveEntry>> {
 	private static final List<String> SUFFIXES = Collections
 			.unmodifiableList(Arrays.asList(".tar")); //$NON-NLS-1$
 
@@ -57,7 +57,7 @@ public final class TarFormat extends BaseFormat implements
 	}
 
 	@Override
-	public void putEntry(ArchiveOutputStream out,
+	public void putEntry(ArchiveOutputStream<TarArchiveEntry> out,
 			ObjectId tree, String path, FileMode mode, ObjectLoader loader)
 			throws IOException {
 		if (mode == FileMode.SYMLINK) {
diff --git a/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/Tbz2Format.java b/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/Tbz2Format.java
index 26da431147..03a2305e2b 100644
--- a/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/Tbz2Format.java
+++ b/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/Tbz2Format.java
@@ -17,6 +17,7 @@ import java.util.List;
 import java.util.Map;
 
 import org.apache.commons.compress.archivers.ArchiveOutputStream;
+import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
 import org.apache.commons.compress.compressors.bzip2.BZip2CompressorOutputStream;
 import org.eclipse.jgit.api.ArchiveCommand;
 import org.eclipse.jgit.lib.FileMode;
@@ -26,12 +27,12 @@ import org.eclipse.jgit.lib.ObjectLoader;
 /**
  * bzip2-compressed tarball (tar.bz2) format.
  */
-public final class Tbz2Format extends BaseFormat implements
-		ArchiveCommand.Format<ArchiveOutputStream> {
+public final class Tbz2Format extends BaseFormat
+		implements ArchiveCommand.Format<ArchiveOutputStream<TarArchiveEntry>> {
 	private static final List<String> SUFFIXES = Collections
 			.unmodifiableList(Arrays.asList(".tar.bz2", ".tbz", ".tbz2")); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 
-	private final ArchiveCommand.Format<ArchiveOutputStream> tarFormat = new TarFormat();
+	private final ArchiveCommand.Format<ArchiveOutputStream<TarArchiveEntry>> tarFormat = new TarFormat();
 
 	@Override
 	public ArchiveOutputStream createArchiveOutputStream(OutputStream s)
@@ -54,7 +55,7 @@ public final class Tbz2Format extends BaseFormat implements
 	}
 
 	@Override
-	public void putEntry(ArchiveOutputStream out,
+	public void putEntry(ArchiveOutputStream<TarArchiveEntry> out,
 			ObjectId tree, String path, FileMode mode, ObjectLoader loader)
 			throws IOException {
 		tarFormat.putEntry(out, tree, path, mode, loader);
diff --git a/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TgzFormat.java b/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TgzFormat.java
index d1ed035d0f..6ce9c1e748 100644
--- a/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TgzFormat.java
+++ b/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TgzFormat.java
@@ -17,6 +17,7 @@ import java.util.List;
 import java.util.Map;
 
 import org.apache.commons.compress.archivers.ArchiveOutputStream;
+import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
 import org.apache.commons.compress.compressors.gzip.GzipCompressorOutputStream;
 import org.apache.commons.compress.compressors.gzip.GzipParameters;
 import org.eclipse.jgit.api.ArchiveCommand;
@@ -27,12 +28,12 @@ import org.eclipse.jgit.lib.ObjectLoader;
 /**
  * gzip-compressed tarball (tar.gz) format.
  */
-public final class TgzFormat extends BaseFormat implements
-		ArchiveCommand.Format<ArchiveOutputStream> {
+public final class TgzFormat extends BaseFormat
+		implements ArchiveCommand.Format<ArchiveOutputStream<TarArchiveEntry>> {
 	private static final List<String> SUFFIXES = Collections
 			.unmodifiableList(Arrays.asList(".tar.gz", ".tgz")); //$NON-NLS-1$ //$NON-NLS-2$
 
-	private final ArchiveCommand.Format<ArchiveOutputStream> tarFormat = new TarFormat();
+	private final ArchiveCommand.Format<ArchiveOutputStream<TarArchiveEntry>> tarFormat = new TarFormat();
 
 	@Override
 	public ArchiveOutputStream createArchiveOutputStream(OutputStream s)
@@ -57,7 +58,7 @@ public final class TgzFormat extends BaseFormat implements
 	}
 
 	@Override
-	public void putEntry(ArchiveOutputStream out,
+	public void putEntry(ArchiveOutputStream<TarArchiveEntry> out,
 			ObjectId tree, String path, FileMode mode, ObjectLoader loader)
 			throws IOException {
 		tarFormat.putEntry(out, tree, path, mode, loader);
diff --git a/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TxzFormat.java b/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TxzFormat.java
index 42549de302..f51f904bc7 100644
--- a/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TxzFormat.java
+++ b/org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TxzFormat.java
@@ -17,6 +17,7 @@ import java.util.List;
 import java.util.Map;
 
 import org.apache.commons.compress.archivers.ArchiveOutputStream;
+import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
 import org.apache.commons.compress.compressors.xz.XZCompressorOutputStream;
 import org.eclipse.jgit.api.ArchiveCommand;
 import org.eclipse.jgit.lib.FileMode;
@@ -26,12 +27,12 @@ import org.eclipse.jgit.lib.ObjectLoader;
 /**
  * Xz-compressed tar (tar.xz) format.
  */
-public final class TxzFormat extends BaseFormat implements
-		ArchiveCommand.Format<ArchiveOutputStream> {
+public final class TxzFormat extends BaseFormat
+		implements ArchiveCommand.Format<ArchiveOutputStream<TarArchiveEntry>> {
 	private static final List<String> SUFFIXES = Collections
 			.unmodifiableList(Arrays.asList(".tar.xz", ".txz")); //$NON-NLS-1$ //$NON-NLS-2$
 
-	private final ArchiveCommand.Format<ArchiveOutputStream> tarFormat = new TarFormat();
+	private final ArchiveCommand.Format<ArchiveOutputStream<TarArchiveEntry>> tarFormat = new TarFormat();
 
 	@Override
 	public ArchiveOutputStream createArchiveOutputStream(OutputStream s)
@@ -54,7 +55,7 @@ public final class TxzFormat extends BaseFormat implements
 	}
 
 	@Override
-	public void putEntry(ArchiveOutputStream out,
+	public void putEntry(ArchiveOutputStream<TarArchiveEntry> out,
 			ObjectId tree, String path, FileMode mode, ObjectLoader loader)
 			throws IOException {
 		tarFormat.putEntry(out, tree, path, mode, loader);
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/BitmapIndexTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/BitmapIndexTest.java
new file mode 100644
index 0000000000..ee4fa8bcc7
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/BitmapIndexTest.java
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2024, Google Inc. and others
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Distribution License v. 1.0 which is available at
+ * https://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+package org.eclipse.jgit.lib;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import org.eclipse.jgit.internal.storage.file.FileRepository;
+import org.eclipse.jgit.internal.storage.file.GC;
+import org.eclipse.jgit.junit.LocalDiskRepositoryTestCase;
+import org.eclipse.jgit.junit.TestRepository;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
+import org.junit.Before;
+import org.junit.Test;
+
+public class BitmapIndexTest extends LocalDiskRepositoryTestCase {
+
+  private static final String MAIN = "refs/heads/main";
+
+  TestRepository<FileRepository> repo;
+
+  RevCommit tipWithBitmap;
+
+  @Override
+  @Before
+  public void setUp() throws Exception {
+    super.setUp();
+    FileRepository db = createWorkRepository();
+    repo = new TestRepository<>(db);
+
+    RevCommit base = repo.commit().create();
+    RevCommit one = repo.commit().parent(base).create();
+    tipWithBitmap = repo.commit().parent(one).create();
+    repo.update(MAIN, tipWithBitmap);
+
+    GC gc = new GC(repo.getRepository());
+    gc.setAuto(false);
+    gc.gc().get();
+
+    assertNotNull(repo.getRevWalk().getObjectReader().getBitmapIndex());
+  }
+
+
+  @Test
+  public void listener_getBitmap_counted() throws Exception {
+    try (RevWalk rw = repo.getRevWalk();
+        ObjectReader or = rw.getObjectReader()) {
+      BitmapLookupCounter counter = new BitmapLookupCounter();
+      BitmapIndex bitmapIndex = or.getBitmapIndex();
+      bitmapIndex.addBitmapLookupListener(counter);
+
+      bitmapIndex.getBitmap(tipWithBitmap);
+      bitmapIndex.getBitmap(tipWithBitmap);
+      bitmapIndex.getBitmap(ObjectId.zeroId());
+
+      assertEquals(2, counter.bitmapFound);
+      assertEquals(1, counter.bitmapNotFound);
+    }
+  }
+
+	private static class BitmapLookupCounter
+			implements BitmapIndex.BitmapLookupListener {
+		int bitmapFound = 0;
+
+		int bitmapNotFound = 0;
+
+		@Override
+		public void onBitmapFound(AnyObjectId oid) {
+			bitmapFound += 1;
+		}
+
+		@Override
+		public void onBitmapNotFound(AnyObjectId oid) {
+			bitmapNotFound += 1;
+		}
+	}
+}
\ No newline at end of file
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/FooterLineTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/FooterLineTest.java
index 01f6a3a0a0..303aedcd00 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/FooterLineTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/FooterLineTest.java
@@ -318,6 +318,57 @@ public class FooterLineTest extends RepositoryTestCase {
 		assertFalse("not CC", line.matches(FooterKey.CC));
 	}
 
+	@Test
+	public void testMultilineFooters() {
+		String msg = buildMessage("subject\n\nbody of commit\n"
+				+ "Not-A-Footer-Line: this line must not be read as a footer\n"
+				+ "\n" // paragraph break, now footers appear in final block
+				+ "Notes: The change must not be merged until dependency ABC is\n"
+				+ " updated.\n"
+				+ "CC:            <some.mailing.list@example.com>\n"
+				+ "not really a footer line but we'll skip it anyway\n"
+				+ "Acked-by: Some Reviewer <sr@example.com>\n");
+		List<FooterLine> footers = FooterLine.fromMessage(msg);
+		FooterLine f;
+
+		assertNotNull(footers);
+		assertEquals(3, footers.size());
+
+		f = footers.get(0);
+		assertEquals("Notes", f.getKey());
+		assertEquals(
+				"The change must not be merged until dependency ABC is updated.",
+				f.getValue());
+
+		f = footers.get(1);
+		assertEquals("CC", f.getKey());
+		assertEquals("<some.mailing.list@example.com>", f.getValue());
+
+		f = footers.get(2);
+		assertEquals("Acked-by", f.getKey());
+		assertEquals("Some Reviewer <sr@example.com>", f.getValue());
+	}
+
+	@Test
+	public void testMultilineFooters_multipleWhitespaceAreAllowed() {
+		String msg = buildMessage("subject\n\nbody of commit\n"
+				+ "Not-A-Footer-Line: this line must not be read as a footer\n"
+				+ "\n" // paragraph break, now footers appear in final block
+				+ "Notes: The change must not be merged until dependency ABC is\n"
+				+ "    updated.\n");
+		List<FooterLine> footers = FooterLine.fromMessage(msg);
+		FooterLine f;
+
+		assertNotNull(footers);
+		assertEquals(1, footers.size());
+
+		f = footers.get(0);
+		assertEquals("Notes", f.getKey());
+		assertEquals(
+				"The change must not be merged until dependency ABC is updated.",
+				f.getValue());
+	}
+
 	private String buildMessage(String msg) {
 		StringBuilder buf = new StringBuilder();
 		buf.append("tree " + ObjectId.zeroId().name() + "\n");
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/BitmapIndexImpl.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/BitmapIndexImpl.java
index 8d8c6a0455..5602158d2d 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/BitmapIndexImpl.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/BitmapIndexImpl.java
@@ -38,6 +38,8 @@ public class BitmapIndexImpl implements BitmapIndex {
 
 	final int indexObjectCount;
 
+	private BitmapLookupListener listener = BitmapLookupListener.NOOP;
+
 	/**
 	 * Creates a BitmapIndex that is back by Compressed bitmaps.
 	 *
@@ -57,8 +59,11 @@ public class BitmapIndexImpl implements BitmapIndex {
 	@Override
 	public CompressedBitmap getBitmap(AnyObjectId objectId) {
 		EWAHCompressedBitmap compressed = packIndex.getBitmap(objectId);
-		if (compressed == null)
+		if (compressed == null) {
+			listener.onBitmapNotFound(objectId);
 			return null;
+		}
+		listener.onBitmapFound(objectId);
 		return new CompressedBitmap(compressed, this);
 	}
 
@@ -67,6 +72,15 @@ public class BitmapIndexImpl implements BitmapIndex {
 		return new CompressedBitmapBuilder(this);
 	}
 
+	@Override
+	public void addBitmapLookupListener(BitmapLookupListener listener) {
+		if (listener == null) {
+			throw new IllegalArgumentException(
+					"Use NOOP instance for no listener"); // @NON-NLS-1@
+		}
+		this.listener = listener;
+	}
+
 	int findPosition(AnyObjectId objectId) {
 		int position = packIndex.findPosition(objectId);
 		if (position < 0) {
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/BitmapIndex.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/BitmapIndex.java
index 97b5847f91..acaa6335d4 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/BitmapIndex.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/BitmapIndex.java
@@ -40,6 +40,58 @@ public interface BitmapIndex {
 	BitmapBuilder newBitmapBuilder();
 
 	/**
+	 * Report the results of {@link #getBitmap(AnyObjectId)}
+	 *
+	 * @since 6.8
+	 */
+	interface BitmapLookupListener {
+
+		/**
+		 * This object has a bitmap in the index
+		 *
+		 * @param oid
+		 *            object id
+		 */
+		void onBitmapFound(AnyObjectId oid);
+
+		/**
+		 * This object does not have a bitmap in the index
+		 *
+		 * @param oid
+		 *            object id
+		 */
+		void onBitmapNotFound(AnyObjectId oid);
+
+		/**
+		 * No-op instance
+		 */
+		BitmapLookupListener NOOP = new BitmapLookupListener() {
+			@Override
+			public void onBitmapFound(AnyObjectId oid) {
+				// Nothing to do
+			}
+
+			@Override
+			public void onBitmapNotFound(AnyObjectId oid) {
+				// Nothing to do
+			}
+		};
+	}
+
+	/**
+	 * Report to this listener whether {@link #getBitmap(AnyObjectId)} finds a
+	 * commit.
+	 *
+	 * @param listener
+	 *            instance listening to lookup events in the index. Never null.
+	 *            Set to {@link BitmapLookupListener#NOOP} to disable.
+	 * @since 6.8
+	 */
+	default void addBitmapLookupListener(BitmapLookupListener listener) {
+		// Empty implementation for API compatibility
+	}
+
+	/**
 	 * A bitmap representation of ObjectIds that can be iterated to return the
 	 * underlying {@code ObjectId}s or operated on with other {@code Bitmap}s.
 	 */
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/BitmapWalker.java b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/BitmapWalker.java
index c0e41d644a..7e65ffb8f6 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/BitmapWalker.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/BitmapWalker.java
@@ -48,76 +48,6 @@ public final class BitmapWalker {
 	private Bitmap prevBitmap;
 
 	/**
-	 * Report commits found during the walk
-	 *
-	 * @since 6.8
-	 */
-	public interface BitmapWalkListener {
-		/**
-		 * The commit was already visited or is reachable from a visited commit
-		 *
-		 * @param oid
-		 *            objectId of the commit already visited directly or
-		 *            indirectly
-		 */
-		void onCommitSeen(ObjectId oid);
-
-		/**
-		 * The commit has a bitmap in the bitmap index
-		 *
-		 * @param oid
-		 *            objectId of the commit with a bitmap in the bitmap index
-		 */
-		void onCommitWithBitmap(ObjectId oid);
-
-		/**
-		 * The commit doesn't have bitmap
-		 *
-		 * @param oid
-		 *            objectId of the commit without a bitmap in the bitmap
-		 *            index
-		 */
-		void onCommitWithoutBitmap(ObjectId oid);
-
-	}
-
-	/**
-	 * Empty listener
-	 *
-	 * @since 6.8
-	 */
-	public static final BitmapWalkListener NOOP_LISTENER = new BitmapWalkListener() {
-		@Override
-		public void onCommitSeen(ObjectId oid) {
-			// Nothing to do
-		}
-
-		@Override
-		public void onCommitWithBitmap(ObjectId oid) {
-			// Nothing to do
-		}
-
-		@Override
-		public void onCommitWithoutBitmap(ObjectId oid) {
-			// Nothing to do
-		}
-	};
-
-	private final BitmapWalkListener listener;
-
-	/**
-	 * Create a BitmapWalker.
-	 *
-	 * @param walker walker to use when traversing the object graph.
-	 * @param bitmapIndex index to obtain bitmaps from.
-	 * @param pm progress monitor to report progress on.
-	 */
-	public BitmapWalker(
-			ObjectWalk walker, BitmapIndex bitmapIndex, ProgressMonitor pm) {
-		this(walker, bitmapIndex, pm, NOOP_LISTENER);
-	}
-
-	/**
 	 * Create a BitmapWalker.
 	 *
 	 * @param walker
@@ -126,18 +56,12 @@ public final class BitmapWalker {
 	 *            index to obtain bitmaps from.
 	 * @param pm
 	 *            progress monitor to report progress on.
-	 * @param listener
-	 *            listener of event happening during the walk. Use
-	 *            {@link BitmapWalker#NOOP_LISTENER} for a no-op listener.
-	 *
-	 * @since 6.8
 	 */
 	public BitmapWalker(ObjectWalk walker, BitmapIndex bitmapIndex,
-			ProgressMonitor pm, BitmapWalkListener listener) {
+			ProgressMonitor pm) {
 		this.walker = walker;
 		this.bitmapIndex = bitmapIndex;
 		this.pm = (pm == null) ? NullProgressMonitor.INSTANCE : pm;
-		this.listener = listener;
 	}
 
 	/**
@@ -219,7 +143,6 @@ public final class BitmapWalker {
 			Bitmap bitmap = bitmapIndex.getBitmap(obj);
 			if (bitmap != null) {
 				result.or(bitmap);
-				listener.onCommitWithBitmap(obj);
 			}
 		}
 
@@ -260,7 +183,6 @@ public final class BitmapWalker {
 			Bitmap bitmap = bitmapIndex.getBitmap(obj);
 			if (bitmap != null) {
 				bitmapResult.or(bitmap);
-				listener.onCommitWithBitmap(obj);
 			}
 		}
 
@@ -290,8 +212,7 @@ public final class BitmapWalker {
 			}
 			walker.setObjectFilter(new BitmapObjectFilter(bitmapResult));
 
-			ObjectId oid;
-			while ((oid = walker.next()) != null) {
+			while (walker.next() != null) {
 				// Iterate through all of the commits. The BitmapRevFilter does
 				// the work.
 				//
@@ -303,7 +224,6 @@ public final class BitmapWalker {
 				// of bitmaps.
 				pm.update(1);
 				countOfBitmapIndexMisses++;
-				listener.onCommitWithoutBitmap(oid);
 			}
 
 			RevObject ro;
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/FooterLine.java b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/FooterLine.java
index 2d396d57c5..cadeaec6e0 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/FooterLine.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/FooterLine.java
@@ -74,41 +74,42 @@ public final class FooterLine {
 	 */
 	public static List<FooterLine> fromMessage(
 			byte[] raw) {
-		int ptr = raw.length - 1;
-		while (raw[ptr] == '\n') // trim any trailing LFs, not interesting
-			ptr--;
+		// Find the end of the last paragraph.
+		int parEnd = raw.length;
+		for (; parEnd > 0 && (raw[parEnd - 1] == '\n' || raw[parEnd - 1] == ' '); --parEnd);
 
 		int msgB = RawParseUtils.commitMessage(raw, 0);
 		ArrayList<FooterLine> r = new ArrayList<>(4);
 		Charset enc = RawParseUtils.guessEncoding(raw);
-		for (;;) {
-			ptr = RawParseUtils.prevLF(raw, ptr);
-			if (ptr <= msgB)
-				break; // Don't parse commit headers as footer lines.
 
-			int keyStart = ptr + 2;
-			if (raw[keyStart] == '\n')
-				break; // Stop at first paragraph break, no footers above it.
+		// Search for the beginning of last paragraph
+		int parStart = parEnd;
+		for (; parStart > msgB && (raw[parStart - 1] != '\n' || raw[parStart - 2] != '\n'); --parStart);
 
-			int keyEnd = RawParseUtils.endOfFooterLineKey(raw, keyStart);
-			if (keyEnd < 0)
-				continue; // Not a well formed footer line, skip it.
+		for (int ptr = parStart; ptr < parEnd;) {
+			int keyStart = ptr;
+			int keyEnd = RawParseUtils.endOfFooterLineKey(raw, ptr);
+			if (keyEnd < 0) {
+				// Not a well-formed footer line, skip it.
+				ptr = RawParseUtils.nextLF(raw, ptr);
+				continue;
+			}
 
 			// Skip over the ': *' at the end of the key before the value.
-			//
-			int valStart = keyEnd + 1;
-			while (valStart < raw.length && raw[valStart] == ' ')
-				valStart++;
-
-			// Value ends at the LF, and does not include it.
-			//
-			int valEnd = RawParseUtils.nextLF(raw, valStart);
-			if (raw[valEnd - 1] == '\n')
-				valEnd--;
-
+			int valStart, valEnd;
+			for (valStart = keyEnd + 1; valStart < raw.length && raw[valStart] == ' '; ++valStart);
+
+			for(ptr = valStart;;) {
+				ptr = RawParseUtils.nextLF(raw, ptr);
+				// Next line starts with whitespace for a multiline footer.
+				if (ptr == raw.length || raw[ptr] != ' ') {
+					valEnd = raw[ptr - 1] == '\n' ? ptr - 1 : ptr;
+					break;
+				}
+			}
 			r.add(new FooterLine(raw, enc, keyStart, keyEnd, valStart, valEnd));
 		}
-		Collections.reverse(r);
+
 		return r;
 	}
 
@@ -199,7 +200,7 @@ public final class FooterLine {
 	 *         character encoding.
 	 */
 	public String getValue() {
-		return RawParseUtils.decode(enc, buffer, valStart, valEnd);
+		return RawParseUtils.decode(enc, buffer, valStart, valEnd).replaceAll("\n +", " ");
 	}
 
 	/**
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevCommit.java b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevCommit.java
index 0392ea428c..1f0f13152e 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevCommit.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevCommit.java
@@ -570,8 +570,9 @@ public class RevCommit extends RevObject {
 	 * the order of the line's appearance in the commit message itself.
 	 * <p>
 	 * A footer line's key must match the pattern {@code ^[A-Za-z0-9-]+:}, while
-	 * the value is free-form, but must not contain an LF. Very common keys seen
-	 * in the wild are:
+	 * the value is free-form. The Value may be split over multiple lines with
+	 * each subsequent line starting with at least one whitespace. Very common
+	 * keys seen in the wild are:
 	 * <ul>
 	 * <li>{@code Signed-off-by} (agrees to Developer Certificate of Origin)
 	 * <li>{@code Acked-by} (thinks change looks sane in context)
diff --git a/tools/BUILD b/tools/BUILD
index 1d29d76604..c2b2366c49 100644
--- a/tools/BUILD
+++ b/tools/BUILD
@@ -53,7 +53,7 @@ java_package_configuration(
         "-Xep:ArraysAsListPrimitiveArray:ERROR",
         "-Xep:ArrayToString:ERROR",
         "-Xep:AssertEqualsArgumentOrderChecker:ERROR",
-        "-Xep:AssertionFailureIgnored:ERROR",
+        "-Xep:AssertionFailureIgnored:WARN",
         "-Xep:AsyncCallableReturnsNull:ERROR",
         "-Xep:AsyncFunctionReturnsNull:ERROR",
         "-Xep:AutoValueConstructorOrderChecker:ERROR",
@@ -62,7 +62,7 @@ java_package_configuration(
         "-Xep:AutoValueSubclassLeaked:WARN",
         "-Xep:BadAnnotationImplementation:ERROR",
         "-Xep:BadComparable:ERROR",
-        "-Xep:BadImport:ERROR",
+        "-Xep:BadImport:WARN",
         "-Xep:BadInstanceof:ERROR",
         "-Xep:BadShiftAmount:ERROR",
         "-Xep:BanSerializableRead:ERROR",
@@ -75,8 +75,8 @@ java_package_configuration(
         "-Xep:CacheLoaderNull:ERROR",
         "-Xep:CannotMockFinalClass:ERROR",
         "-Xep:CanonicalDuration:ERROR",
-        "-Xep:CatchAndPrintStackTrace:ERROR",
-        "-Xep:CatchFail:ERROR",
+        "-Xep:CatchAndPrintStackTrace:WARN",
+        "-Xep:CatchFail:WARN",
         "-Xep:ChainedAssertionLosesContext:ERROR",
         "-Xep:ChainingConstructorIgnoresParameter:ERROR",
         "-Xep:CharacterGetNumericValue:ERROR",
@@ -123,7 +123,7 @@ java_package_configuration(
         "-Xep:DurationGetTemporalUnit:ERROR",
         "-Xep:DurationTemporalUnit:ERROR",
         "-Xep:DurationToLongTimeUnit:ERROR",
-        "-Xep:EmptyBlockTag:ERROR",
+        "-Xep:EmptyBlockTag:WARN",
         "-Xep:EmptyCatch:ERROR",
         "-Xep:EmptySetMultibindingContributions:ERROR",
         "-Xep:EqualsGetClass:ERROR",
@@ -158,7 +158,7 @@ java_package_configuration(
         "-Xep:FromTemporalAccessor:ERROR",
         "-Xep:FunctionalInterfaceClash:ERROR",
         "-Xep:FunctionalInterfaceMethodChanged:ERROR",
-        "-Xep:FutureReturnValueIgnored:ERROR",
+        "-Xep:FutureReturnValueIgnored:WARN",
         "-Xep:FuturesGetCheckedIllegalExceptionType:ERROR",
         "-Xep:GetClassOnAnnotation:ERROR",
         "-Xep:GetClassOnClass:ERROR",
@@ -167,7 +167,7 @@ java_package_configuration(
         "-Xep:GuiceAssistedInjectScoping:ERROR",
         "-Xep:GuiceAssistedParameters:ERROR",
         "-Xep:HashtableContains:ERROR",
-        "-Xep:HidingField:ERROR",
+        "-Xep:HidingField:WARN",
         "-Xep:IdentityBinaryExpression:ERROR",
         "-Xep:IdentityHashMapBoxing:ERROR",
         "-Xep:IdentityHashMapUsage:ERROR",
@@ -251,7 +251,7 @@ java_package_configuration(
         "-Xep:LockOnBoxedPrimitive:ERROR",
         "-Xep:LogicalAssignment:ERROR",
         "-Xep:LongFloatConversion:ERROR",
-        "-Xep:LongLiteralLowerCaseSuffix:ERROR",
+        "-Xep:LongLiteralLowerCaseSuffix:WARN",
         "-Xep:LoopConditionChecker:ERROR",
         "-Xep:LoopOverCharArray:ERROR",
         "-Xep:LossyPrimitiveCompare:ERROR",
@@ -270,7 +270,7 @@ java_package_configuration(
         "-Xep:MixedDescriptors:ERROR",
         "-Xep:MixedMutabilityReturnType:WARN",
         "-Xep:MockitoUsage:ERROR",
-        "-Xep:ModifiedButNotUsed:ERROR",
+        "-Xep:ModifiedButNotUsed:WARN",
         "-Xep:ModifyCollectionInEnhancedForLoop:ERROR",
         "-Xep:ModifyingCollectionWithItself:ERROR",
         "-Xep:ModifySourceCollectionInStream:ERROR",
@@ -323,7 +323,7 @@ java_package_configuration(
         "-Xep:PreferredInterfaceType:OFF",
         "-Xep:PrimitiveAtomicReference:ERROR",
         "-Xep:PrivateSecurityContractProtoAccess:ERROR",
-        "-Xep:ProtectedMembersInFinalClass:ERROR",
+        "-Xep:ProtectedMembersInFinalClass:WARN",
         "-Xep:ProtoBuilderReturnValueIgnored:ERROR",
         "-Xep:ProtocolBufferOrdinal:ERROR",
         "-Xep:ProtoDurationGetSecondsGetNano:ERROR",
@@ -372,7 +372,7 @@ java_package_configuration(
         "-Xep:ThreadJoinLoop:ERROR",
         "-Xep:ThreadLocalUsage:ERROR",
         "-Xep:ThreadPriorityCheck:ERROR",
-        "-Xep:ThreeLetterTimeZoneID:ERROR",
+        "-Xep:ThreeLetterTimeZoneID:WARN",
         "-Xep:ThrowIfUncheckedKnownChecked:ERROR",
         "-Xep:ThrowNull:ERROR",
         "-Xep:TimeUnitConversionChecker:ERROR",
@@ -389,14 +389,14 @@ java_package_configuration(
         "-Xep:TypeParameterQualifier:ERROR",
         "-Xep:TypeParameterShadowing:ERROR",
         "-Xep:TypeParameterUnusedInFormals:ERROR",
-        "-Xep:UndefinedEquals:ERROR",
-        "-Xep:UnescapedEntity:ERROR",
+        "-Xep:UndefinedEquals:WARN",
+        "-Xep:UnescapedEntity:WARN",
         "-Xep:UnnecessaryAssignment:ERROR",
         "-Xep:UnnecessaryCheckNotNull:ERROR",
         "-Xep:UnnecessaryLambda:ERROR",
         "-Xep:UnnecessaryMethodInvocationMatcher:ERROR",
         "-Xep:UnnecessaryMethodReference:ERROR",
-        "-Xep:UnnecessaryParentheses:ERROR",
+        "-Xep:UnnecessaryParentheses:WARN",
         "-Xep:UnnecessaryTypeArgument:ERROR",
         "-Xep:UnrecognisedJavadocTag:ERROR",
         "-Xep:UnsafeFinalization:ERROR",
@@ -405,12 +405,12 @@ java_package_configuration(
         "-Xep:UnusedAnonymousClass:ERROR",
         "-Xep:UnusedCollectionModifiedInPlace:ERROR",
         "-Xep:UnusedException:ERROR",
-        "-Xep:UnusedMethod:ERROR",
+        "-Xep:UnusedMethod:WARN",
         "-Xep:UnusedNestedClass:ERROR",
-        "-Xep:UnusedVariable:ERROR",
+        "-Xep:UnusedVariable:WARN",
         "-Xep:URLEqualsHashCode:ERROR",
         "-Xep:UseBinds:ERROR",
-        "-Xep:UseCorrectAssertInTests:ERROR",
+        "-Xep:UseCorrectAssertInTests:WARN",
         "-Xep:VariableNameSameAsType:ERROR",
         "-Xep:VarTypeName:ERROR",
         "-Xep:WaitNotInLoop:ERROR",