From 6094c6fc2fc30eb9ee7c2f9f1088a851f71bf1b9 Mon Sep 17 00:00:00 2001 From: Serhiy Storchaka Date: Thu, 8 Aug 2024 09:48:11 +0300 Subject: [PATCH] gh-116263: Do not rollover empty files in RotatingFileHandler (GH-122788) --- Lib/logging/handlers.py | 7 ++- Lib/test/test_logging.py | 54 +++++++++++++++++-- ...-08-07-17-41-16.gh-issue-116263.EcXir0.rst | 2 + 3 files changed, 58 insertions(+), 5 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2024-08-07-17-41-16.gh-issue-116263.EcXir0.rst diff --git a/Lib/logging/handlers.py b/Lib/logging/handlers.py index 0fa40f56e99..1cba64fd554 100644 --- a/Lib/logging/handlers.py +++ b/Lib/logging/handlers.py @@ -196,9 +196,12 @@ class RotatingFileHandler(BaseRotatingHandler): if self.stream is None: # delay was set... self.stream = self._open() if self.maxBytes > 0: # are we rolling over? + pos = self.stream.tell() + if not pos: + # gh-116263: Never rollover an empty file + return False msg = "%s\n" % self.format(record) - self.stream.seek(0, 2) #due to non-posix-compliant Windows feature - if self.stream.tell() + len(msg) >= self.maxBytes: + if pos + len(msg) >= self.maxBytes: # See bpo-45401: Never rollover anything other than regular files if os.path.exists(self.baseFilename) and not os.path.isfile(self.baseFilename): return False diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py index 49523756e11..39189495654 100644 --- a/Lib/test/test_logging.py +++ b/Lib/test/test_logging.py @@ -6196,13 +6196,28 @@ class FileHandlerTest(BaseFileTest): self.assertEqual(fp.read().strip(), '1') class RotatingFileHandlerTest(BaseFileTest): - @unittest.skipIf(support.is_wasi, "WASI does not have /dev/null.") def test_should_not_rollover(self): - # If maxbytes is zero rollover never occurs + # If file is empty rollover never occurs + rh = logging.handlers.RotatingFileHandler( + self.fn, encoding="utf-8", maxBytes=1) + self.assertFalse(rh.shouldRollover(None)) + rh.close() + + # If maxBytes is zero rollover never occurs rh = logging.handlers.RotatingFileHandler( self.fn, encoding="utf-8", maxBytes=0) self.assertFalse(rh.shouldRollover(None)) rh.close() + + with open(self.fn, 'wb') as f: + f.write(b'\n') + rh = logging.handlers.RotatingFileHandler( + self.fn, encoding="utf-8", maxBytes=0) + self.assertFalse(rh.shouldRollover(None)) + rh.close() + + @unittest.skipIf(support.is_wasi, "WASI does not have /dev/null.") + def test_should_not_rollover_non_file(self): # bpo-45401 - test with special file # We set maxBytes to 1 so that rollover would normally happen, except # for the check for regular files @@ -6212,18 +6227,47 @@ class RotatingFileHandlerTest(BaseFileTest): rh.close() def test_should_rollover(self): - rh = logging.handlers.RotatingFileHandler(self.fn, encoding="utf-8", maxBytes=1) + with open(self.fn, 'wb') as f: + f.write(b'\n') + rh = logging.handlers.RotatingFileHandler(self.fn, encoding="utf-8", maxBytes=2) self.assertTrue(rh.shouldRollover(self.next_rec())) rh.close() def test_file_created(self): # checks that the file is created and assumes it was created # by us + os.unlink(self.fn) rh = logging.handlers.RotatingFileHandler(self.fn, encoding="utf-8") rh.emit(self.next_rec()) self.assertLogFile(self.fn) rh.close() + def test_max_bytes(self, delay=False): + kwargs = {'delay': delay} if delay else {} + os.unlink(self.fn) + rh = logging.handlers.RotatingFileHandler( + self.fn, encoding="utf-8", backupCount=2, maxBytes=100, **kwargs) + self.assertIs(os.path.exists(self.fn), not delay) + small = logging.makeLogRecord({'msg': 'a'}) + large = logging.makeLogRecord({'msg': 'b'*100}) + self.assertFalse(rh.shouldRollover(small)) + self.assertFalse(rh.shouldRollover(large)) + rh.emit(small) + self.assertLogFile(self.fn) + self.assertFalse(os.path.exists(self.fn + ".1")) + self.assertFalse(rh.shouldRollover(small)) + self.assertTrue(rh.shouldRollover(large)) + rh.emit(large) + self.assertTrue(os.path.exists(self.fn)) + self.assertLogFile(self.fn + ".1") + self.assertFalse(os.path.exists(self.fn + ".2")) + self.assertTrue(rh.shouldRollover(small)) + self.assertTrue(rh.shouldRollover(large)) + rh.close() + + def test_max_bytes_delay(self): + self.test_max_bytes(delay=True) + def test_rollover_filenames(self): def namer(name): return name + ".test" @@ -6232,11 +6276,15 @@ class RotatingFileHandlerTest(BaseFileTest): rh.namer = namer rh.emit(self.next_rec()) self.assertLogFile(self.fn) + self.assertFalse(os.path.exists(namer(self.fn + ".1"))) rh.emit(self.next_rec()) self.assertLogFile(namer(self.fn + ".1")) + self.assertFalse(os.path.exists(namer(self.fn + ".2"))) rh.emit(self.next_rec()) self.assertLogFile(namer(self.fn + ".2")) self.assertFalse(os.path.exists(namer(self.fn + ".3"))) + rh.emit(self.next_rec()) + self.assertFalse(os.path.exists(namer(self.fn + ".3"))) rh.close() def test_namer_rotator_inheritance(self): diff --git a/Misc/NEWS.d/next/Library/2024-08-07-17-41-16.gh-issue-116263.EcXir0.rst b/Misc/NEWS.d/next/Library/2024-08-07-17-41-16.gh-issue-116263.EcXir0.rst new file mode 100644 index 00000000000..167ca943b35 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2024-08-07-17-41-16.gh-issue-116263.EcXir0.rst @@ -0,0 +1,2 @@ +:class:`logging.handlers.RotatingFileHandler` no longer rolls over empty log +files.