imported module no longer available

[Jeff Dyke]

I've come across an error that i'm not yet able to create a test case
for but wanted to get see if someone could shed light on this.

I have imported a module at the top of my file with
import mymodulename

this module is used many times in the current file successfully, but
then I attempt to use it one more time and get: UnboundLocalError:
local variable 'mymodulename' referenced before assignment

if i add `print globals().keys()` right before the line where the
error occurs l see the module in the list (actual output, names
changed to protect the innocent)
['HPADao', 'RDao', 'DriverBase', 'FKSUtility', 'PMDao',
'mymodulename', 'IDriver', 'DriverTrack', 'HPPDao', 'setLogName',
'HPDao', 'iparser', '__builtins__', '__file__', 'driver', '_LOGNAME',
'sys', 'IClient', '__name__', 'copy', 'types', 'logging', 'iloader',
'HPADao', '__doc__', 'PMDao', 'time', 'FormatLoad']
Traceback (most recent call last):
File "testunbound.py", line 475, in <module>
driver.getRData('0605', 22528)
File "testunbound.py", line 256, in getRData
print mymodulename

the code that generates these two lines is:
print globals().keys()
print mymodulename

I can solve this by placing
import mymodulename again in this method, but can't have that everywhere.

I will try to come up with a generic reproduction of this issue, but
that might take some time. I've also seen this in the past with the
python builtin 'sys'
I did see a bug http://bugs.python.org/issue2378, which has very
similar behaviour, but is different.

Python 2.5, ubuntu hardy

Thanks for any insight,
Jeff

[Mark Tolonen]

"Jeff Dyke" <je*******@gmail.comwrote in message
news:ma************************************@python .org...

I've come across an error that i'm not yet able to create a test case
for but wanted to get see if someone could shed light on this.

I have imported a module at the top of my file with
import mymodulename

this module is used many times in the current file successfully, but
then I attempt to use it one more time and get: UnboundLocalError:
local variable 'mymodulename' referenced before assignment

if i add `print globals().keys()` right before the line where the
error occurs l see the module in the list (actual output, names
changed to protect the innocent)
['HPADao', 'RDao', 'DriverBase', 'FKSUtility', 'PMDao',
'mymodulename', 'IDriver', 'DriverTrack', 'HPPDao', 'setLogName',
'HPDao', 'iparser', '__builtins__', '__file__', 'driver', '_LOGNAME',
'sys', 'IClient', '__name__', 'copy', 'types', 'logging', 'iloader',
'HPADao', '__doc__', 'PMDao', 'time', 'FormatLoad']
Traceback (most recent call last):
File "testunbound.py", line 475, in <module>
driver.getRData('0605', 22528)
File "testunbound.py", line 256, in getRData
print mymodulename

the code that generates these two lines is:
print globals().keys()
print mymodulename

I can solve this by placing
import mymodulename again in this method, but can't have that everywhere.

I will try to come up with a generic reproduction of this issue, but
that might take some time. I've also seen this in the past with the
python builtin 'sys'
I did see a bug http://bugs.python.org/issue2378, which has very
similar behaviour, but is different.

Python 2.5, ubuntu hardy

Thanks for any insight,
Jeff

That error will occur if somewhere in a function or method you accidently
assign another value to a global variable, without declaring it with the
global keyword first, even if it occurs later in the function. Example:

import os
print os.getcwd()
def func():
print globals().keys()
print os
os=1
func()

OUTPUT:

c:\
['__builtins__', '__file__', 'func', '__name__', 'os', '__doc__']
Traceback (most recent call last):
File
"C:\dev\python\Lib\site-packages\pythonwin\pywin\framework\scriptutils.py" ,
line 414, in ImportFile
exec codeObj in __main__.__dict__
File "<auto import>", line 1, in <module>
File "test.py", line 10, in <module>
func()
File "test.py", line 7, in func
print os
UnboundLocalError: local variable 'os' referenced before assignment

Check in the function that caused the error to see if later in the code the
module name is being used as a local variable.

--Mark