Exception AttributeError: AttributeError("'NoneType' object has no attribute 'unlink'",) in <bound method LockedFile.__del__ of <__main__.LockedFile object at 0x26b8d50>> ignored

[gashev]

% tox
GLOB sdist-make: /tmp/crudini/setup.py
py26 create: /tmp/crudini/.tox/py26
py26 installdeps: iniparse
py26 inst: /tmp/crudini/.tox/dist/crudini-0.4.zip
py26 runtests: PYTHONHASHSEED='3324528470'
py26 runtests: commands[0] | /bin/bash -c cd tests && ./test.sh
Test 1 OK (line 32)
Exception AttributeError: AttributeError("'NoneType' object has no attribute 'unlink'",) in <bound method LockedFile.__del__ of <__main__.LockedFile object at 0x26b8d50>> ignored
Test 2 OK (line 39)

tox stopped on test2 and process run:

% strace -p 13320
^[[6~Process 13320 attached - interrupt to quit
select(0, NULL, NULL, NULL, {0, 677151}) = 0 (Timeout)
open(".test.ini.crudini.lck", O_RDONLY|O_CREAT|O_EXCL, 0) = -1 EEXIST (File exists)
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
open(".test.ini.crudini.lck", O_RDONLY|O_CREAT|O_EXCL, 0) = -1 EEXIST (File exists)
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
open(".test.ini.crudini.lck", O_RDONLY|O_CREAT|O_EXCL, 0) = -1 EEXIST (File exists)
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
open(".test.ini.crudini.lck", O_RDONLY|O_CREAT|O_EXCL, 0) = -1 EEXIST (File exists)
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
open(".test.ini.crudini.lck", O_RDONLY|O_CREAT|O_EXCL, 0) = -1 EEXIST (File exists)
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
open(".test.ini.crudini.lck", O_RDONLY|O_CREAT|O_EXCL, 0) = -1 EEXIST (File exists)
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
open(".test.ini.crudini.lck", O_RDONLY|O_CREAT|O_EXCL, 0) = -1 EEXIST (File exists)

% uname -a
Linux hp 3.15.1 #2 SMP Sun Jun 22 18:33:35 UTC 2014 x86_64 GNU/Linux
% cat /etc/issue
Debian GNU/Linux 7 \n \l

[pixelb]

Weird. Can't repro here on 2.7 or python 2.6. Also I can't correlate the code to the exception message.

You'll need to remove the .test.ini.crudini.lck file manually

[gashev]

I need remove .test.ini.crudini.lck file after every test:

% tox
GLOB sdist-make: /tmp/crudini/setup.py
py26 create: /tmp/crudini/.tox/py26
py26 installdeps: iniparse
py26 inst: /tmp/crudini/.tox/dist/crudini-0.4.zip
py26 runtests: PYTHONHASHSEED='4056784320'
py26 runtests: commands[0] | /bin/bash -c cd tests && ./test.sh
Test 1 OK (line 32)
Exception AttributeError: AttributeError("'NoneType' object has no attribute 'unlink'",) in <bound method LockedFile.__del__ of <__main__.LockedFile object at 0x296cd50>> ignored
Test 2 OK (line 39)
Exception AttributeError: AttributeError("'NoneType' object has no attribute 'unlink'",) in <bound method LockedFile.__del__ of <__main__.LockedFile object at 0x1fb8d50>> ignored
Test 3 OK (line 44)
Exception AttributeError: AttributeError("'NoneType' object has no attribute 'unlink'",) in <bound method LockedFile.__del__ of <__main__.LockedFile object at 0x16cbd50>> ignored
Test 4 OK (line 50)
Exception AttributeError: AttributeError("'NoneType' object has no attribute 'unlink'",) in <bound method LockedFile.__del__ of <__main__.LockedFile object at 0x2024d50>> ignored
Test 5 OK (line 55)

[pixelb]

Right because the unlink isn't happening, But the code only does "os.unlink(...)", so it thinks that "os" is None ??

[gashev]

Yes, os is NoneType. You call os.unlink to del call. In this time os already destroyed?

[pixelb]

Drats so it's racy. It's surprising I didn't hit this in all the times I ran the test. Does the following address it for you?

diff --git a/crudini b/crudini
index 3daeb6c..ebe7a0e 100755
--- a/crudini
+++ b/crudini
@@ -8,6 +8,7 @@
 # under the terms of the GPLv2, the GNU General Public License version 2, as
 # published by the Free Software Foundation. http://gnu.org/licenses/gpl.html

+import atexit
 import os
 import sys
 import errno
@@ -323,6 +324,8 @@ class LockedFile(FileLock):
         self.filename = filename
         self.operation = operation

+        atexit.register(self.delete)
+
         FileLock.__init__(self, operation != "--get", not inplace)

         if inplace:
@@ -350,9 +353,10 @@ class LockedFile(FileLock):
             error(str(e))
             sys.exit(1)

-    def __del__(self):
+    def delete(self):
         # explicit close so closed in correct order
-        # if taking lock multiple times
+        # if taking lock multiple times or also avoiding
+        # os module being destroyed first etc.
         self.unlock()
         if self.fp:
             self.fp.close()

[gashev]

It's ok now. I ran tox some times, issue is not reproduced.

[pixelb]

Fixed in commit 7108dd7

Thanks for the hint and testing!