fileinput device or resource busy error

[meren]

BPO	1336582
Nosy	@malemburg, @birkenfeld

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/malemburg'
closed_at = <Date 2006-02-19.09:52:12.000>
created_at = <Date 2005-10-24.17:03:30.000>
labels = ['expert-unicode']
title = 'fileinput device or resource busy error'
updated_at = <Date 2006-02-19.09:52:12.000>
user = 'https://bugs.python.org/meren'

bugs.python.org fields:

activity = <Date 2006-02-19.09:52:12.000>
actor = 'georg.brandl'
assignee = 'lemburg'
closed = True
closed_date = None
closer = None
components = ['Unicode']
creation = <Date 2005-10-24.17:03:30.000>
creator = 'meren'
dependencies = []
files = []
hgrepos = []
issue_num = 1336582
keywords = []
message_count = 2.0
messages = ['26687', '26688']
nosy_count = 3.0
nosy_names = ['lemburg', 'georg.brandl', 'meren']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue1336582'
versions = []

[meren]

Fileinput module can't work with the unicode path names
properly.

Here is the reproduction of the error:

---------------8<---------------8<---------------8<---------------8<-------

meren@pardus /home/meren $ touch myfile
meren@pardus /home/meren $ python
>>> fn = u'/home/meren/myfile'
>>> type(fn)
<type 'unicode'>
>>> import fileinput
>>> for line in fileinput.input(fn, inplace = 1):
...     print line
...
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/usr/lib/python2.3/fileinput.py", line 231, in next
    line = self.readline()
  File "/usr/lib/python2.3/fileinput.py", line 300, in
readline
    os.rename(self._filename, self._backupfilename)
OSError: [Errno 16] Device or resource busy
>>> 
--------------->8--------------->8--------------->8--------------->8

---

This is happening, because the value of the
self._filename variable is just the first character of
the fn: '/'.

The __init__ method of the FileInput class
(/usr/lib/python2.3/fileinput.py) is the responsible
one about this malfunction. In the __init__ function
it's checking the type of the 'files' variable (in this
case it is fn) for an iteration hack:

---------------8<---------------8<---------------8<---------------8<-------
(...)
def __init__(self, files=None, inplace=0,
backup="", bufsize=0):
if type(files) == type(''):
files = (files,)
(...)
--------------->8--------------->8--------------->8--------------->8-------

When the type of the 'files' variable is unicode, the
value of the 'files' variable is incohorently becoming
into this:

files = [u'/', u'h', u'o', u'm', u'e', u'/', u'm',
u'e', u'r', u'e' ....

consequently, python is trying to execute
os.rename('/', '/.bak') instead of
os.rename('/home/meren/myfile',
'/home/meren/myfile.bak'). After this function call os
module decides to throw an error, normally..

[1],
(...)
if isinstance(files, basestring):
files = (files,)
(...)

[2]
(...)
if type(files) == type(''):
files = (files,)
(...)

Checking the type of the variable in the __init__
function of the class like [1] is solving the problem
(now we are doing it like [2]).. Also, no backward
compatibility problem appearing with this replacement.

Here is a small patch to show replacement properly:

---------------8<---------------8<---------------8<---------------8<-------
--- fileinput.orig.py 2005-10-24 19:55:53.019413368 +0300
+++ fileinput.py 2005-10-24 19:56:19.590373968 +0300
@@ -184,7 +184,7 @@
"""

     def __init__(self, files=None, inplace=0,
backup="", bufsize=0):
-        if type(files) == type(''):
+        if isinstance(files, basestring):
             files = (files,)
         else:
             if files is None:
--------------->8--------------->8--------------->8--------------->8

---

and here is the result of the same operation after this
patch:

---------------8<---------------8<---------------8<---------------8<-------

(...)
    os.rename(self._filename, self._backupfilename)
OSError: [Errno 16] Device or resource busy
>>> reload(fileinput)
<module 'fileinput' from '/usr/lib/python2.3/fileinput.py'>
>>> for line in fileinput.input(fn, inplace = 1):
...     print line
...
>>>
--------------->8--------------->8--------------->8--------------->8

---

Sorry for the long explanation,
Thanks in advice..
Ciao.

[birkenfeld]

Logged In: YES
user_id=1188172

Thanks for the report, applied your patch in rev. 42489, 42490.