Create subdirectories if they do not exist when specified for log file

changelog/7467.improvement.rst

@@ -0,0 +1 @@
+``--log-file`` CLI option and ``log_file`` ini marker now create subdirectories if needed.

src/_pytest/logging.py

@@ -531,11 +531,17 @@ def __init__(self, config: Config) -> None:
         # File logging.
         self.log_file_level = get_log_level_for_setting(config, "log_file_level")
         log_file = get_option_ini(config, "log_file") or os.devnull
+        if log_file != os.devnull:
+            directory = os.path.dirname(os.path.abspath(log_file))
+            if not os.path.isdir(directory):
+                os.makedirs(directory)
+
         self.log_file_handler = _FileHandler(log_file, mode="w", encoding="UTF-8")
         log_file_format = get_option_ini(config, "log_file_format", "log_format")
         log_file_date_format = get_option_ini(
             config, "log_file_date_format", "log_date_format"
         )
+
         log_file_formatter = logging.Formatter(
             log_file_format, datefmt=log_file_date_format
         )

testing/logging/test_reporting.py

@@ -5,6 +5,7 @@
 
 import pytest
 from _pytest.capture import CaptureManager
+from _pytest.config import ExitCode
 from _pytest.pytester import Testdir
 from _pytest.terminal import TerminalReporter
 
@@ -1152,3 +1153,11 @@ def test_bad_log(monkeypatch):
     )
     result = testdir.runpytest()
     result.assert_outcomes(passed=1)
+
+
+def test_log_file_cli_subdirectories_are_successfully_created(testdir):
+    path = testdir.makepyfile(""" def test_logger(): pass """)
+    expected = os.path.join(os.path.dirname(str(path)), "foo", "bar")
+    result = testdir.runpytest("--log-file=foo/bar/logf.log")
+    assert "logf.log" in os.listdir(expected)
+    assert result.ret == ExitCode.OK