From 6cf4358aba91aeef6961846e851436449dfc724f Mon Sep 17 00:00:00 2001
From: ace2016 <23010364+ace2016@users.noreply.github.com>
Date: Sat, 22 Aug 2026 19:01:46 +0100
Subject: [PATCH 1/2] Warn when cmdline_main raises SystemExit

---
 changelog/8986.bugfix.rst      |  2 ++
 src/_pytest/config/__init__.py | 10 +++++++++-
 testing/test_config.py         | 15 +++++++++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 changelog/8986.bugfix.rst

diff --git a/changelog/8986.bugfix.rst b/changelog/8986.bugfix.rst
new file mode 100644
index 00000000000..e1c6544ded1
--- /dev/null
+++ b/changelog/8986.bugfix.rst
@@ -0,0 +1,2 @@
+Warn when a plugin raises :class:`SystemExit` from the
+:hook:`pytest_cmdline_main` hook.
diff --git a/src/_pytest/config/__init__.py b/src/_pytest/config/__init__.py
index e0038e26ce6..06046f50f16 100644
--- a/src/_pytest/config/__init__.py
+++ b/src/_pytest/config/__init__.py
@@ -234,7 +234,15 @@ def _main(
             return ExitCode.USAGE_ERROR
 
         try:
-            ret: ExitCode | int = config.hook.pytest_cmdline_main(config=config)
+            try:
+                ret: ExitCode | int = config.hook.pytest_cmdline_main(config=config)
+            except SystemExit:
+                warnings.warn(
+                    PytestConfigWarning(
+                        "A plugin raised SystemExit from the pytest_cmdline_main hook"
+                    )
+                )
+                raise
             try:
                 return ExitCode(ret)
             except ValueError:
diff --git a/testing/test_config.py b/testing/test_config.py
index 1d2aceb0d99..4ad00aab32b 100644
--- a/testing/test_config.py
+++ b/testing/test_config.py
@@ -32,6 +32,7 @@
 from _pytest.monkeypatch import MonkeyPatch
 from _pytest.pathlib import absolutepath
 from _pytest.pytester import Pytester
+from _pytest.warning_types import PytestConfigWarning
 from _pytest.warning_types import PytestDeprecationWarning
 import pytest
 
@@ -852,6 +853,20 @@ def test_absolute_win32_path(self, pytester: Pytester) -> None:
 
 
 class TestConfigAPI:
+    @pytest.mark.parametrize("code", [0, 42])
+    def test_cmdline_main_system_exit(self, code: int) -> None:
+        class Plugin:
+            def pytest_cmdline_main(self, config: Config) -> None:
+                raise SystemExit(code)
+
+        with pytest.warns(
+            PytestConfigWarning,
+            match="plugin raised SystemExit from the pytest_cmdline_main hook",
+        ), pytest.raises(SystemExit) as exc_info:
+            pytest.main([], plugins=[Plugin()])
+
+        assert exc_info.value.code == code
+
     def test_config_trace(self, pytester: Pytester) -> None:
         config = pytester.parseconfig()
         values: list[str] = []

From 28b598c4d98ef3fdb4ebef1fcd0c14bf86d4b683 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sat, 22 Aug 2026 18:19:10 +0000
Subject: [PATCH 2/2] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 testing/test_config.py | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/testing/test_config.py b/testing/test_config.py
index 4ad00aab32b..5645d2b5233 100644
--- a/testing/test_config.py
+++ b/testing/test_config.py
@@ -859,10 +859,13 @@ class Plugin:
             def pytest_cmdline_main(self, config: Config) -> None:
                 raise SystemExit(code)
 
-        with pytest.warns(
-            PytestConfigWarning,
-            match="plugin raised SystemExit from the pytest_cmdline_main hook",
-        ), pytest.raises(SystemExit) as exc_info:
+        with (
+            pytest.warns(
+                PytestConfigWarning,
+                match="plugin raised SystemExit from the pytest_cmdline_main hook",
+            ),
+            pytest.raises(SystemExit) as exc_info,
+        ):
             pytest.main([], plugins=[Plugin()])
 
         assert exc_info.value.code == code