[CI][Bisect][1] Skeleton for automated bisect of release tests (#34329)

A script to bisect release test failures. This PR only contains a skeleton and unit-tests

Signed-off-by: Cuong Nguyen <[email protected]>

release/ray_release/scripts/ray_bisect.py

@@ -0,0 +1,41 @@
+import click
+import subprocess
+from typing import List
+
+
+@click.command()
+@click.argument("test_name", required=True, type=str)
+@click.argument("passing_commit", required=True, type=str)
+@click.argument("failing_commit", required=True, type=str)
+def main(test_name: str, passing_commit: str, failing_commit: str) -> None:
+    commit_lists = _get_commit_lists(passing_commit, failing_commit)
+    blamed_commit = _bisect(test_name, commit_lists)
+    print(f"Blamed commit found: {blamed_commit}")
+
+
+def _bisect(test_name: str, commit_list: List[str]) -> str:
+    while len(commit_list) > 1:
+        middle_commit_idx = len(commit_list) // 2
+        middle_commit = commit_list[middle_commit_idx]
+        is_passing = _run_test(test_name, middle_commit)
+        if is_passing:
+            commit_list = commit_list[middle_commit_idx + 1 :]
+        else:
+            commit_list = commit_list[:middle_commit_idx]
+    return commit_list[-1]
+
+
+def _run_test(test_name: str, commit: str) -> bool:
+    return True
+
+
+def _get_commit_lists(passing_commit: str, failing_commit: str) -> List[str]:
+    commit_lists = subprocess.check_output(
+        f"git rev-list --ancestry-path {passing_commit}..{failing_commit}",
+        shell=True,
+    )
+    return commit_lists.decode("utf-8").split("\n")
+
+
+if __name__ == "__main__":
+    main()

release/ray_release/tests/test_bisect.py

@@ -0,0 +1,22 @@
+from unittest import mock
+from ray_release.scripts.ray_bisect import _bisect
+
+
+def test_bisect():
+    commit_to_test_result = {
+        "c0": True,
+        "c1": True,
+        "c2": True,
+        "c3": False,
+        "c4": False,
+    }
+
+    def _mock_run_test(test_name: str, commit: str) -> bool:
+        return commit_to_test_result[commit]
+
+    with mock.patch(
+        "ray_release.scripts.ray_bisect._run_test",
+        side_effect=_mock_run_test,
+    ):
+        blamed_commit = _bisect("test", list(commit_to_test_result.keys()))
+        assert blamed_commit == "c3"