From b506bfb54e5e26a1403ef9782e8b4ca9c109209d Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Sun, 26 Nov 2023 01:00:10 +0100
Subject: [PATCH 1/3] Add CoW warning builds

---
 .github/workflows/unit-tests.yml | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/.github/workflows/unit-tests.yml b/.github/workflows/unit-tests.yml
index 33b6e7a8c2340..4c38324280528 100644
--- a/.github/workflows/unit-tests.yml
+++ b/.github/workflows/unit-tests.yml
@@ -73,6 +73,14 @@ jobs:
             env_file: actions-311.yaml
             pattern: "not slow and not network and not single_cpu"
             pandas_copy_on_write: "warn"
+          - name: "Copy-on-Write 3.10 (warnings)"
+            env_file: actions-310.yaml
+            pattern: "not slow and not network and not single_cpu"
+            pandas_copy_on_write: "warn"
+          - name: "Copy-on-Write 3.9 (warnings)"
+            env_file: actions-39.yaml
+            pattern: "not slow and not network and not single_cpu"
+            pandas_copy_on_write: "warn"
           - name: "Pypy"
             env_file: actions-pypy-39.yaml
             pattern: "not slow and not network and not single_cpu"

From 2834bbb2146a20112b9c34a6089a9748f04ed337 Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Sun, 26 Nov 2023 01:04:31 +0100
Subject: [PATCH 2/3] Fix warnings for inplace ops

---
 pandas/core/generic.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index e4e95a973a3c1..7b48e9137fd8d 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -12450,7 +12450,7 @@ def _inplace_method(self, other, op) -> Self:
         """
         warn = True
         if not PYPY and warn_copy_on_write():
-            if sys.getrefcount(self) <= 4:
+            if sys.getrefcount(self) <= REF_COUNT * 2:
                 # we are probably in an inplace setitem context (e.g. df['a'] += 1)
                 warn = False
 

From f4d1eeee9707ea2feee496690de51738493f76cc Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Sun, 26 Nov 2023 01:05:16 +0100
Subject: [PATCH 3/3] Revert "Fix warnings for inplace ops"

This reverts commit 2834bbb2146a20112b9c34a6089a9748f04ed337.
---
 pandas/core/generic.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 7b48e9137fd8d..e4e95a973a3c1 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -12450,7 +12450,7 @@ def _inplace_method(self, other, op) -> Self:
         """
         warn = True
         if not PYPY and warn_copy_on_write():
-            if sys.getrefcount(self) <= REF_COUNT * 2:
+            if sys.getrefcount(self) <= 4:
                 # we are probably in an inplace setitem context (e.g. df['a'] += 1)
                 warn = False