[Python-Dev] BZ2File.writelines should raise more meaningful exceptions

[Lawrence Oluyede]

In the BZ2File object of bz2 module the writelines() method does not
check its closed state before doing the actual work so its behavior
it's different from write()'s behavior. See:

>>> from bz2 import BZ2File
>>> f = BZ2File("foo", "w")
>>> f.close()
>>> f.closed
1
>>> f.write("foobar")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: I/O operation on closed file
>>> f.closed
1
>>> f.writelines(["foobar"])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IOError: unknown IO error

It also doesn't check if it can write for real:

>>> from bz2 import BZ2File
>>> f = BZ2File("foo", "r")
>>> f.write("foobar")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IOError: file is not ready for writing
>>> f.writelines(['foobar'])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
RuntimeError: wrong sequence of bz2 library commands used

The patch is attached. If you think it's ok to fix this I'll post it
to the bug tracker

-- 
Lawrence
http://www.oluyede.org/blog
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: bz2module.diff.txt
Url: http://mail.python.org/pipermail/python-dev/attachments/20060806/bd63dc42/attachment.txt