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

@@ -585,11 +585,14 @@ def filtering(self, filter_: logging.Filter) -> Generator[None]:
 
         .. versionadded:: 7.5
         """
-        self.handler.addFilter(filter_)
+        already_present = filter_ in self.handler.filters
+        if not already_present:
+            self.handler.addFilter(filter_)
         try:
             yield
         finally:
-            self.handler.removeFilter(filter_)
+            if not already_present:
+                self.handler.removeFilter(filter_)
 
 
 @fixture

testing/logging/test_fixture.py

@@ -4,6 +4,7 @@
 
 from collections.abc import Iterator
 import logging
+from typing import cast
 
 from _pytest.logging import caplog_records_key
 from _pytest.pytester import Pytester
@@ -69,8 +70,7 @@ def test_change_level_undo(pytester: Pytester) -> None:
 
     Tests the logging output themselves (affected both by logger and handler levels).
     """
-    pytester.makepyfile(
-        """
+    pytester.makepyfile("""
         import logging
 
         def test1(caplog):
@@ -83,8 +83,7 @@ def test2(caplog):
             # using + operator here so fnmatch_lines doesn't match the code in the traceback
             logging.info('log from ' + 'test2')
             assert 0
-    """
-    )
+    """)
     result = pytester.runpytest()
     result.stdout.fnmatch_lines(["*log from test1*", "*2 failed in *"])
     result.stdout.no_fnmatch_line("*log from test2*")
@@ -95,8 +94,7 @@ def test_change_disabled_level_undo(pytester: Pytester) -> None:
 
     Tests the logging output themselves (affected by disabled logging level).
     """
-    pytester.makepyfile(
-        """
+    pytester.makepyfile("""
         import logging
 
         def test1(caplog):
@@ -112,8 +110,7 @@ def test2(caplog):
             # isn't reset to ``CRITICAL`` after test1.
             logging.warning('log from ' + 'test2')
             assert 0
-    """
-    )
+    """)
     result = pytester.runpytest()
     result.stdout.fnmatch_lines(["*log from test1*", "*2 failed in *"])
     result.stdout.no_fnmatch_line("*log from test2*")
@@ -124,8 +121,7 @@ def test_change_level_undoes_handler_level(pytester: Pytester) -> None:
 
     Issue #7569. Tests the handler level specifically.
     """
-    pytester.makepyfile(
-        """
+    pytester.makepyfile("""
         import logging
 
         def test1(caplog):
@@ -141,8 +137,7 @@ def test3(caplog):
             assert caplog.handler.level == 0
             caplog.set_level(43)
             assert caplog.handler.level == 43
-    """
-    )
+    """)
     result = pytester.runpytest()
     result.assert_outcomes(passed=3)
 
@@ -206,6 +201,37 @@ def filter(self, record: logging.LogRecord) -> bool:
     assert unfiltered_tuple == ("test_fixture", 20, "handler call")
 
 
+def test_with_statement_nested_filtering(caplog: pytest.LogCaptureFixture) -> None:
+    def no_capture_filter(log_record: logging.LogRecord) -> bool:
+        return False
+
+    with caplog.filtering(cast(logging.Filter, no_capture_filter)):
+        logger.warning("Will not be captured")
+        with caplog.filtering(cast(logging.Filter, no_capture_filter)):
+            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:
+    def no_capture_filter(log_record: logging.LogRecord) -> bool:
+        return False
+
+    caplog.handler.addFilter(no_capture_filter)
+    try:
+        with caplog.filtering(cast(logging.Filter, no_capture_filter)):
+            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(no_capture_filter)
+
+
 @pytest.mark.parametrize(
     "level_str,expected_disable_level",
     [
@@ -346,8 +372,7 @@ def test_clear_for_call_stage(
 
 
 def test_ini_controls_global_log_level(pytester: Pytester) -> None:
-    pytester.makepyfile(
-        """
+    pytester.makepyfile("""
         import pytest
         import logging
         def test_log_level_override(request, caplog):
@@ -358,23 +383,19 @@ def test_log_level_override(request, caplog):
             logger.error("ERROR message will be shown")
             assert 'WARNING' not in caplog.text
             assert 'ERROR' in caplog.text
-    """
-    )
-    pytester.makeini(
-        """
+    """)
+    pytester.makeini("""
         [pytest]
         log_level=ERROR
-    """
-    )
+    """)
 
     result = pytester.runpytest()
     # make sure that we get a '0' exit code for the testsuite
     assert result.ret == 0
 
 
 def test_can_override_global_log_level(pytester: Pytester) -> None:
-    pytester.makepyfile(
-        """
+    pytester.makepyfile("""
         import pytest
         import logging
         def test_log_level_override(request, caplog):
@@ -398,22 +419,18 @@ def test_log_level_override(request, caplog):
             logger.info("INFO message will be shown")
 
             assert "message won't be shown" not in caplog.text
-    """
-    )
-    pytester.makeini(
-        """
+    """)
+    pytester.makeini("""
         [pytest]
         log_level=WARNING
-    """
-    )
+    """)
 
     result = pytester.runpytest()
     assert result.ret == 0
 
 
 def test_captures_despite_exception(pytester: Pytester) -> None:
-    pytester.makepyfile(
-        """
+    pytester.makepyfile("""
         import pytest
         import logging
         def test_log_level_override(request, caplog):
@@ -426,14 +443,11 @@ def test_log_level_override(request, caplog):
             with caplog.at_level(logging.DEBUG, logger.name):
                 logger.debug("DEBUG message " + "won't be shown")
                 raise Exception()
-    """
-    )
-    pytester.makeini(
-        """
+    """)
+    pytester.makeini("""
         [pytest]
         log_level=WARNING
-    """
-    )
+    """)
 
     result = pytester.runpytest()
     result.stdout.fnmatch_lines(["*ERROR message will be shown*"])
@@ -449,8 +463,7 @@ def test_log_report_captures_according_to_config_option_upon_failure(
     (2) The `DEBUG` message does NOT appear in the `Captured log call` report.
     (3) The stdout, `INFO`, and `WARNING` messages DO appear in the test reports due to `--log-level=INFO`.
     """
-    pytester.makepyfile(
-        """
+    pytester.makepyfile("""
         import pytest
         import logging
 
@@ -471,8 +484,7 @@ def test_that_fails(request, caplog):
                 raise Exception('caplog failed to ' + 'capture DEBUG')
 
             assert False
-    """
-    )
+    """)
 
     result = pytester.runpytest("--log-level=INFO")
     result.stdout.no_fnmatch_line("*Exception: caplog failed to capture DEBUG*")