logging: fix handler level restored incorrectly if caplog.set_level is called more than once

changelog/7672.bugfix.rst

@@ -0,0 +1 @@
+Fixed log-capturing level restored incorrectly if ``caplog.set_level`` is called more than once.

src/_pytest/logging.py

@@ -439,7 +439,8 @@ def set_level(self, level: Union[int, str], logger: Optional[str] = None) -> Non
         # Save the original log-level to restore it during teardown.
         self._initial_logger_levels.setdefault(logger, logger_obj.level)
         logger_obj.setLevel(level)
-        self._initial_handler_level = self.handler.level
+        if self._initial_handler_level is None:
+            self._initial_handler_level = self.handler.level
         self.handler.setLevel(level)
 
     @contextmanager

testing/logging/test_fixture.py

@@ -65,6 +65,7 @@ def test_change_level_undos_handler_level(testdir: Testdir) -> None:
 
         def test1(caplog):
             assert caplog.handler.level == 0
+            caplog.set_level(9999)
             caplog.set_level(41)
             assert caplog.handler.level == 41