Issue #9759: GzipFile now raises ValueError when an operation is attempted
after the file is closed. Patch by Jeffrey Finkelstein.
diff --git a/Lib/gzip.py b/Lib/gzip.py
index 7c3fd51..21b1404 100644
--- a/Lib/gzip.py
+++ b/Lib/gzip.py
@@ -210,6 +210,13 @@
s = repr(fileobj)
return '<gzip ' + s[1:-1] + ' ' + hex(id(self)) + '>'
+ 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 @@
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 @@
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 @@
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 8e493b5..4a364c2 100644
--- a/Lib/test/test_gzip.py
+++ b/Lib/test/test_gzip.py
@@ -62,6 +62,28 @@
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 7042774..e62dc77 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -88,6 +88,9 @@
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.