1 files changed, 63 insertions, 0 deletions
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/RewriteGeneratorTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/RewriteGeneratorTest.java
new file mode 100644
index 0000000000..04e372998c
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/RewriteGeneratorTest.java
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2023, HIS eG
+ *
+ * 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.revwalk;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import org.junit.Test;
+
+public class RewriteGeneratorTest extends RevWalkTestCase {
+
+	@Test
+	public void testRewriteGeneratorDoesNotExhaustPreviousGenerator()
+			throws Exception {
+		RevCommit a = commit();
+		a.flags |= RevWalk.TREE_REV_FILTER_APPLIED;
+		RevCommit b = commit(a);
+
+		LIFORevQueue q = new LIFORevQueue();
+		q.add(a);
+		q.add(b);
+
+		/*
+		 * Since the TREE_REV_FILTER has been applied to commit a and the
+		 * REWRITE flag has not been applied to commit a, the RewriteGenerator
+		 * must not rewrite the parent of b and thus must not call the previous
+		 * generator (since b already has its correct parent).
+		 */
+		RewriteGenerator rewriteGenerator = new RewriteGenerator(q);
+		rewriteGenerator.next();
+
+		assertNotNull(
+				"Previous generator was unnecessarily exhausted by RewriteGenerator",
+				q.next());
+	}
+
+	@Test
+	public void testRewriteGeneratorRewritesParent() throws Exception {
+		RevCommit a = commit();
+		a.flags |= RevWalk.TREE_REV_FILTER_APPLIED;
+		a.flags |= RevWalk.REWRITE;
+		RevCommit b = commit(a);
+		assertEquals(1, b.getParentCount());
+
+		LIFORevQueue q = new LIFORevQueue();
+		/*
+		 * We are only adding commit b (and not a), because PendingGenerator
+		 * should never emit a commit that has the REWRITE flag set.
+		 */
+		q.add(b);
+
+		RewriteGenerator rewriteGenerator = new RewriteGenerator(q);
+		RevCommit returnedB = rewriteGenerator.next();
+		assertEquals(b.getId(), returnedB.getId());
+		assertEquals(0, returnedB.getParentCount());
+	}
+}