diff options
Diffstat (limited to 'Lib/test/test_io.py')
| -rw-r--r-- | Lib/test/test_io.py | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py index 168e66c5a3f..b487bcabf01 100644 --- a/Lib/test/test_io.py +++ b/Lib/test/test_io.py @@ -9,6 +9,7 @@ # * test_univnewlines - tests universal newline support # * test_largefile - tests operations on a file greater than 2**32 bytes # (only enabled with -ulargefile) +# * test_free_threading/test_io - tests thread safety of io objects ################################################################################ # ATTENTION TEST WRITERS!!! @@ -1062,6 +1063,37 @@ class IOTest(unittest.TestCase): # Silence destructor error R.flush = lambda self: None + @threading_helper.requires_working_threading() + def test_write_readline_races(self): + # gh-134908: Concurrent iteration over a file caused races + thread_count = 2 + write_count = 100 + read_count = 100 + + def writer(file, barrier): + barrier.wait() + for _ in range(write_count): + file.write("x") + + def reader(file, barrier): + barrier.wait() + for _ in range(read_count): + for line in file: + self.assertEqual(line, "") + + with self.open(os_helper.TESTFN, "w+") as f: + barrier = threading.Barrier(thread_count + 1) + reader = threading.Thread(target=reader, args=(f, barrier)) + writers = [threading.Thread(target=writer, args=(f, barrier)) + for _ in range(thread_count)] + with threading_helper.catch_threading_exception() as cm: + with threading_helper.start_threads(writers + [reader]): + pass + self.assertIsNone(cm.exc_type) + + self.assertEqual(os.stat(os_helper.TESTFN).st_size, + write_count * thread_count) + class CIOTest(IOTest): |