[PR #14284/c7f9e75c backport][9.1.x] Fix nested caplog.filtering early removal

changelog/14189.bugfix.rst

@@ -0,0 +1 @@
+Nested usage of :meth:`caplog.filtering <pytest.LogCaptureFixture.filtering>` no longer removes filters early if they were already present.

src/_pytest/logging.py

@@ -600,11 +600,15 @@ def filtering(self, filter_: logging.Filter) -> Generator[None]:
 
         .. versionadded:: 7.5
         """
-        self.handler.addFilter(filter_)
-        try:
+        already_present = filter_ in self.handler.filters
+        if already_present:
             yield
-        finally:
-            self.handler.removeFilter(filter_)
+        else:
+            try:
+                self.handler.addFilter(filter_)
+                yield
+            finally:
+                self.handler.removeFilter(filter_)
 
 
 @fixture

testing/logging/test_fixture.py

@@ -206,6 +206,40 @@ def filter(self, record: logging.LogRecord) -> bool:
     assert unfiltered_tuple == ("test_fixture", 20, "handler call")
 
 
+class DropAllFilter(logging.Filter):
+    def filter(self, record: logging.LogRecord) -> bool:
+        return False
+
+
+def test_with_statement_nested_filtering(caplog: pytest.LogCaptureFixture) -> None:
+    drop_all = DropAllFilter()
+
+    with caplog.filtering(drop_all):
+        logger.warning("Will not be captured")
+        with caplog.filtering(drop_all):
+            logger.warning("Will also not be captured")
+        logger.warning("Should not be captured either")
+
+    assert caplog.records == []
+
+
+def test_with_statement_filtering_already_present(
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    drop_all = DropAllFilter()
+
+    caplog.handler.addFilter(drop_all)
+    try:
+        with caplog.filtering(drop_all):
+            logger.warning("Should not be captured")
+
+        # After context manager, filter should STILL be present because it was already there
+        logger.warning("Should still not be captured")
+        assert caplog.records == []
+    finally:
+        caplog.handler.removeFilter(drop_all)
+
+
 @pytest.mark.parametrize(
     "level_str,expected_disable_level",
     [