Consider alternative to using Exception.message to get message text

[wtriplett]

Summary

Apparently, some Exception classes may not have a .message attribute. This can be more problematic when catching base Exception and then trying to log/warn using a string incorporating the original Exception's .message attribute. Maybe using str(ex) is more compatible, or more specific exception classes?

Example (from master):

nipype/nipype/utils/filemanip.py

Lines 866 to 877 in b356ad1

	try:
	proc = sp.Popen(
	command, stdout=sp.PIPE, stderr=sp.PIPE, shell=True, env=environ
	)
	o, e = proc.communicate()
	deps = o.rstrip()
	except Exception as ex:
	deps = '"%s" failed' % command
	fmlogger.warning(
	"Could not get dependencies of %s. Error:\n%s", name, ex.message
	)
	return deps

will cause a throw exception if an OSError is caught, since OSError does not have a .message attribute (at least in python 3.8.3)

Actual behavior

Python 3.8.3 (default, May 19 2020, 18:47:26) 
[GCC 7.3.0] :: Anaconda, Inc. on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> a = OSError('darn')
>>> a.message
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'OSError' object has no attribute 'message'

Expected behavior

>>> str(a)
'darn'

[effigies]

I agree, let's move to str.