diff --git a/cli/src/commands/rebase.rs b/cli/src/commands/rebase.rs
index 08d13ffe494..e51ad78ed5a 100644
--- a/cli/src/commands/rebase.rs
+++ b/cli/src/commands/rebase.rs
@@ -382,14 +382,19 @@ fn rebase_revision(
     let num_rebased_descendants = rebased_commit_ids.len();
 
     // We now update `new_parents` to account for the rebase of all of
-    // `old_commit`'s descendants. Even if some of the original `new_parents` were
-    // descendants of `old_commit`, this will no longer be the case after the
-    // update.
+    // `old_commit`'s descendants. Even if some of the original `new_parents`
+    // were descendants of `old_commit`, this will no longer be the case after
+    // the update.
     //
     // To make the update simpler, we assume that each commit was rewritten only
     // once; we don't have a situation where both `(A,B)` and `(B,C)` are in
-    // `rebased_commit_ids`. This assumption relies on the fact that a descendant of
-    // a child of `old_commit` cannot also be a direct child of `old_commit`.
+    // `rebased_commit_ids`.
+    // TODO(ilyagr): This assumption relies on the fact that, after
+    // `rebase_descendants`, a child of `old_commit` cannot also be a direct
+    // child of `old_commit`. This will likely change, see
+    // https://github.com/martinvonz/jj/issues/2600. So, the code needs to be
+    // updated before that happens. This will also affect
+    // `test_rebase_with_child_and_descendant_bug_2600`.
     let new_parents: Vec<_> = new_parents
         .iter()
         .map(|new_parent| {
diff --git a/cli/tests/test_rebase_command.rs b/cli/tests/test_rebase_command.rs
index 07b19c8dc3e..3e29cf94f07 100644
--- a/cli/tests/test_rebase_command.rs
+++ b/cli/tests/test_rebase_command.rs
@@ -631,3 +631,145 @@ fn test_rebase_with_descendants() {
 fn get_log_output(test_env: &TestEnvironment, repo_path: &Path) -> String {
     test_env.jj_cmd_success(repo_path, &["log", "-T", "branches"])
 }
+
+// This behavior illustrates https://github.com/martinvonz/jj/issues/2600
+// The behavior of `rebase -r A -d descendant_of_A` can also be affected or
+// broken depending on how #2600 is fixed, so we test that as well.
+#[test]
+fn test_rebase_with_child_and_descendant_bug_2600() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_ok(test_env.env_root(), &["init", "repo", "--git"]);
+    let repo_path = test_env.env_root().join("repo");
+
+    create_commit(&test_env, &repo_path, "base", &[]);
+    create_commit(&test_env, &repo_path, "a", &["base"]);
+    create_commit(&test_env, &repo_path, "b", &["base", "a"]);
+    create_commit(&test_env, &repo_path, "c", &["b"]);
+    let setup_opid = test_env.current_operation_id(&repo_path);
+
+    // Test the setup
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    @  c
+    ◉    b
+    ├─╮
+    │ ◉  a
+    ├─╯
+    ◉  base
+    ◉
+    "###);
+
+    let (stdout, stderr) =
+        test_env.jj_cmd_ok(&repo_path, &["rebase", "-r", "base", "-d", "root()"]);
+    insta::assert_snapshot!(stdout, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    Also rebased 4 descendant commits onto parent of rebased commit
+    Working copy now at: vruxwmqv 1fdab507 c | c
+    Parent commit      : royxmykx 4d413a39 b | b
+    Added 0 files, modified 0 files, removed 1 files
+    "###);
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    ◉  base
+    │ @  c
+    │ ◉  b
+    │ ◉  a
+    ├─╯
+    ◉
+    "###);
+
+    let (stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["rebase", "-r", "base", "-d", "b"]);
+    insta::assert_snapshot!(stdout, @"");
+    insta::assert_snapshot!(stderr, @"");
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    ◉  base
+    │ @  c
+    ├─╯
+    ◉  b
+    ◉  a
+    ◉
+    "###);
+
+    let (stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["rebase", "-r", "base", "-d", "a"]);
+    insta::assert_snapshot!(stdout, @"");
+    insta::assert_snapshot!(stderr, @"");
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    ◉  base
+    │ @  c
+    │ ◉  b
+    ├─╯
+    ◉  a
+    ◉
+    "###);
+
+    test_env.jj_cmd_ok(&repo_path, &["op", "restore", &setup_opid]);
+    let (stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["rebase", "-r", "a", "-d", "root()"]);
+    insta::assert_snapshot!(stdout, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    Also rebased 2 descendant commits onto parent of rebased commit
+    Working copy now at: vruxwmqv 8d3a8426 c | c
+    Parent commit      : royxmykx 4ea418a3 b | b
+    Added 0 files, modified 0 files, removed 1 files
+    "###);
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    ◉  a
+    │ @  c
+    │ ◉  b
+    │ ◉  base
+    ├─╯
+    ◉
+    "###);
+
+    test_env.jj_cmd_ok(&repo_path, &["op", "restore", &setup_opid]);
+    let (stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["rebase", "-r", "b", "-d", "root()"]);
+    insta::assert_snapshot!(stdout, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    Also rebased 1 descendant commits onto parent of rebased commit
+    Working copy now at: vruxwmqv 62ca8ca6 c | c
+    Parent commit      : zsuskuln 2c5b7858 a | a
+    Added 0 files, modified 0 files, removed 1 files
+    "###);
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    ◉  b
+    │ @  c
+    │ ◉  a
+    │ ◉  base
+    ├─╯
+    ◉
+    "###);
+
+    test_env.jj_cmd_ok(&repo_path, &["op", "restore", &setup_opid]);
+    let (stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["rebase", "-r", "b", "-d", "c"]);
+    insta::assert_snapshot!(stdout, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    Also rebased 1 descendant commits onto parent of rebased commit
+    Working copy now at: vruxwmqv 28f17d8e c | c
+    Parent commit      : zsuskuln 2c5b7858 a | a
+    Added 0 files, modified 0 files, removed 1 files
+    "###);
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    ◉  b
+    @  c
+    ◉  a
+    ◉  base
+    ◉
+    "###);
+
+    // In this test, the commit with weird ancestry is not rebased (neither directly
+    // nor indirectly).
+    test_env.jj_cmd_ok(&repo_path, &["op", "restore", &setup_opid]);
+    let (stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["rebase", "-r", "c", "-d", "a"]);
+    insta::assert_snapshot!(stdout, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    Working copy now at: vruxwmqv ee203f6d c | c
+    Parent commit      : zsuskuln 2c5b7858 a | a
+    Added 0 files, modified 0 files, removed 1 files
+    "###);
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    @  c
+    │ ◉  b
+    ╭─┤
+    ◉ │  a
+    ├─╯
+    ◉  base
+    ◉
+    "###);
+}