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Frequently Asked Questions / Usage tips for PyLint |
Frequently Asked Questions / Usage tips for PyLint
Question:
Is it possible to give file as argument to pylint, instead of module ?
Answer:
pylint expects the name of a package or module as argument. As a convenience, you can give to it a file name if it's possible to guess a module name from the file's path, using the python path. Some examples : "pylint mymodule.py" should always works since the current working directory is automatically added on top of the python path "pylint directory/mymodule.py" will work if "directory" is a python package (i.e. has an __init__.py file) or if "directory" is in the python path. "pylint /whatever/directory/mymodule.py" will work if either:
Question:
I'm using psyobj from psyco and get a lot of spurious "unused variables messages". Is it normal ?
Answer:
Yes. That's actually due to a bug in psyco, making the locals() function for objects inheriting from psyobj returning an empty dictionary. For the moment, the only way to fix this is to use the PYLINT_IMPORT environment variable to not use psyco during pylint checking. Sample code
import os
try:
if os.environ.has_key('PYLINT_IMPORT'):
raise ImportError()
from psyco.classes import psyobj
except ImportError:
class psyobj:
pass
NOTICE: this problem should not occurs with pylint >= 0.5 since from this version pylint is not looking anymore for information in living objects (i.e. it doesn't anymore import analysed modules)
Question:
I've a function / method which is a callback where I do not have any control on received argument, and pylint is complaining about unused arguments. What can I do to avoid those warnings ?
Answer:
prefix (ui) the callback's name by cb_, as in cb_onclick(...). By doing so arguments usage won't be checked. Another solution is to use one of the name defined in the "dummy-variables" configuration variable for unused argument ("_" and "dummy" by default).
Question:
When pylint is considering a class as an interface ?
Answer:
A class is considered as an interface if there is a class named "Interface" somewhere in it ancestor's tree.
Question:
When pylint is considering that a class is implementing a given interface ?
Answer:
Pylint is using the Zope 2 interfaces conventions, and so is considering that a class is implementing interfaces listed in its __implements__ attribute.
Question:
When pylint is considering a class as an abstract class ?
Answer:
A class is considered as an abstract class if at least one of its methods is doing nothing but raising NotImplementedError
Question:
Is there some way to disable some message for a particular module only ?
Answer:
Yes, you can disable or enable (globally disabled) message at the module level by adding the corresponding option in a comment at the top of the file:
# pylint: disable-msg=W0401, E0202
# pylint: enable-msg=C0302
Question:
I've a mixin class relying on attributes of the mixed class, and I would like to not have the "access to undefined member" message on this class. Is it possible ?
Answer:
Yes :o) To do so you have to set the ignore-mixin-members option to "yes" (this is the default value) and to name your mixin class with a name which ends with "mixin" (whatever case) |