bpo-37523: Raise ValueError for I/O operations on a closed zipfile.ZipExtFile. (GH-14658)

danifus · serhiy-storchaka · commit 8d62df60d873 · 2019-11-30T10:30:47.000+02:00
Raises ValueError when calling the following on a closed zipfile.ZipExtFile: read, readable, seek, seekable, tell.
diff --git a/Lib/test/test_zipfile.py b/Lib/test/test_zipfile.py
@@ -571,6 +571,20 @@ def test_write_default_name(self):
             with open(TESTFN, "rb") as f:
                 self.assertEqual(zipfp.read(TESTFN), f.read())
 
+    def test_io_on_closed_zipextfile(self):
+        fname = "somefile.txt"
+        with zipfile.ZipFile(TESTFN2, mode="w") as zipfp:
+            zipfp.writestr(fname, "bogus")
+
+        with zipfile.ZipFile(TESTFN2, mode="r") as zipfp:
+            with zipfp.open(fname) as fid:
+                fid.close()
+                self.assertRaises(ValueError, fid.read)
+                self.assertRaises(ValueError, fid.seek, 0)
+                self.assertRaises(ValueError, fid.tell)
+                self.assertRaises(ValueError, fid.readable)
+                self.assertRaises(ValueError, fid.seekable)
+
     def test_write_to_readonly(self):
         """Check that trying to call write() on a readonly ZipFile object
         raises a ValueError."""
diff --git a/Lib/zipfile.py b/Lib/zipfile.py
@@ -889,12 +889,16 @@ def peek(self, n=1):
         return self._readbuffer[self._offset: self._offset + 512]
 
     def readable(self):
+        if self.closed:
+            raise ValueError("I/O operation on closed file.")
         return True
 
     def read(self, n=-1):
         """Read and return up to n bytes.
         If the argument is omitted, None, or negative, data is read and returned until EOF is reached.
         """
+        if self.closed:
+            raise ValueError("read from closed file.")
         if n is None or n < 0:
             buf = self._readbuffer[self._offset:]
             self._readbuffer = b''
@@ -1031,9 +1035,13 @@ def close(self):
             super().close()
 
     def seekable(self):
+        if self.closed:
+            raise ValueError("I/O operation on closed file.")
         return self._seekable
 
     def seek(self, offset, whence=0):
+        if self.closed:
+            raise ValueError("seek on closed file.")
         if not self._seekable:
             raise io.UnsupportedOperation("underlying stream is not seekable")
         curr_pos = self.tell()
@@ -1082,6 +1090,8 @@ def seek(self, offset, whence=0):
         return self.tell()
 
     def tell(self):
+        if self.closed:
+            raise ValueError("tell on closed file.")
         if not self._seekable:
             raise io.UnsupportedOperation("underlying stream is not seekable")
         filepos = self._orig_file_size - self._left - len(self._readbuffer) + self._offset
diff --git a/Misc/NEWS.d/next/Library/2019-10-02-02-55-37.bpo-37523.GguwJ6.rst b/Misc/NEWS.d/next/Library/2019-10-02-02-55-37.bpo-37523.GguwJ6.rst
@@ -0,0 +1 @@
+Change :class:`zipfile.ZipExtFile` to raise ``ValueError`` when trying to access the underlying file object after it has been closed. This new behavior is consistent with how accessing closed files is handled in other parts of Python.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	+Change :class:`zipfile.ZipExtFile` to raise ``ValueError`` when trying to access the underlying file object after it has been closed. This new behavior is consistent with how accessing closed files is handled in other parts of Python.