From 79e0b5ff49f6bea87be8426ac7d155a1a54da2de Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Wed, 29 Mar 2023 10:04:53 -0400
Subject: [PATCH] Backport PR #52060: API CoW: Return read_only NumPy array
 from ravel

---
 pandas/core/series.py                | 5 ++++-
 pandas/tests/copy_view/test_array.py | 9 +++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/pandas/core/series.py b/pandas/core/series.py
index 1725f754ce065..895b72decd379 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -765,7 +765,10 @@ def ravel(self, order: str = "C") -> ArrayLike:
         --------
         numpy.ndarray.ravel : Return a flattened array.
         """
-        return self._values.ravel(order=order)
+        arr = self._values.ravel(order=order)
+        if isinstance(arr, np.ndarray) and using_copy_on_write():
+            arr.flags.writeable = False
+        return arr
 
     def __len__(self) -> int:
         """
diff --git a/pandas/tests/copy_view/test_array.py b/pandas/tests/copy_view/test_array.py
index 501ef27bc291e..519479881948b 100644
--- a/pandas/tests/copy_view/test_array.py
+++ b/pandas/tests/copy_view/test_array.py
@@ -110,3 +110,12 @@ def test_series_to_numpy(using_copy_on_write):
     arr = ser.to_numpy(dtype="float64")
     assert not np.shares_memory(arr, get_array(ser, "name"))
     assert arr.flags.writeable is True
+
+
+@pytest.mark.parametrize("order", ["F", "C"])
+def test_ravel_read_only(using_copy_on_write, order):
+    ser = Series([1, 2, 3])
+    arr = ser.ravel(order=order)
+    if using_copy_on_write:
+        assert arr.flags.writeable is False
+    assert np.shares_memory(get_array(ser), arr)