diff --git a/Lib/gzip.py b/Lib/gzip.py index 7c3fd5157e7..21b140498f8 100644 --- a/Lib/gzip.py +++ b/Lib/gzip.py @@ -210,6 +210,13 @@ class GzipFile(io.BufferedIOBase): s = repr(fileobj) return '' + def _check_closed(self): + """Raises a ValueError if the underlying file object has been closed. + + """ + if self.closed: + raise ValueError('I/O operation on closed file.') + def _init_write(self, filename): self.name = filename self.crc = zlib.crc32(b"") & 0xffffffff @@ -288,6 +295,7 @@ class GzipFile(io.BufferedIOBase): self._add_read_data(uncompress) def write(self,data): + self._check_closed() if self.mode != WRITE: import errno raise IOError(errno.EBADF, "write() on read-only GzipFile object") @@ -308,6 +316,7 @@ class GzipFile(io.BufferedIOBase): return len(data) def read(self, size=-1): + self._check_closed() if self.mode != READ: import errno raise IOError(errno.EBADF, "read() on write-only GzipFile object") @@ -457,6 +466,7 @@ class GzipFile(io.BufferedIOBase): self.myfileobj = None def flush(self,zlib_mode=zlib.Z_SYNC_FLUSH): + self._check_closed() if self.mode == WRITE: # Ensure the compressor's buffer is flushed self.fileobj.write(self.compress.flush(zlib_mode)) diff --git a/Lib/test/test_gzip.py b/Lib/test/test_gzip.py index 8e493b50000..4a364c21994 100644 --- a/Lib/test/test_gzip.py +++ b/Lib/test/test_gzip.py @@ -62,6 +62,28 @@ class TestGzip(unittest.TestCase): f = gzip.GzipFile(self.filename, 'r') ; d = f.read() ; f.close() self.assertEqual(d, data1*50) + def test_io_on_closed_object(self): + # Test that I/O operations on closed GzipFile objects raise a + # ValueError, just like the corresponding functions on file objects. + + # Write to a file, open it for reading, then close it. + self.test_write() + f = gzip.GzipFile(self.filename, 'r') + f.close() + with self.assertRaises(ValueError): + f.read(1) + with self.assertRaises(ValueError): + f.seek(0) + with self.assertRaises(ValueError): + f.tell() + # Open the file for writing, then close it. + f = gzip.GzipFile(self.filename, 'w') + f.close() + with self.assertRaises(ValueError): + f.write(b'') + with self.assertRaises(ValueError): + f.flush() + def test_append(self): self.test_write() # Append to the previous file diff --git a/Misc/NEWS b/Misc/NEWS index 7042774b672..e62dc77d493 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -88,6 +88,9 @@ Core and Builtins Library ------- +- Issue #9759: GzipFile now raises ValueError when an operation is attempted + after the file is closed. Patch by Jeffrey Finkelstein. + - Issue #9042: Fix interaction of custom translation classes and caching in gettext.