Messages control

In order to control messages, pylint accepts the following values:

• a symbolic message: no-member, undefined-variable etc.

• a numerical ID: E1101, E1102 etc.

• The name of the group of checks. You can grab those with pylint --list-groups. For example, you can disable / enable all the checks related to type checking, with typecheck or all the checks related to variables with variables

• Corresponding category of the checks

  • C convention related checks

  • R refactoring related checks

  • W various warnings

  • E errors, for probable bugs in the code

  • F fatal, if an error occurred which prevented pylint from doing further processing.

• All the checks with all

Block disables

This describes how the pragma controls operate at a code level.

The pragma controls can disable / enable:

• All the violations on a single line

a, b = ... # pylint: disable=unbalanced-tuple-unpacking

• All the violations on the following line

# pylint: disable-next=unbalanced-tuple-unpacking
a, b = ...

• All the violations in a single scope

def test():
    # Disable all the no-member violations in this function
    # pylint: disable=no-member
    ...

• All the violations in a block. For instance, each separate branch of an if statement is considered a separate block, as in the following example:

def meth5(self):
    # pylint: disable=no-member
    # no error
    print(self.bla)
    if self.blop:
        # pylint: enable=no-member
        # enable all no-members for this block
        print(self.blip)
    else:
        # This is affected by the scope disable
        print(self.blip)
    # pylint: enable=no-member
    print(self.blip)
    if self.blop:
        # pylint: disable=no-member
        # disable all no-members for this block
        print(self.blip)
    else:
        # This emits a violation
        print(self.blip)

• If the violation occurs on a block starting line, then it applies only to that line

if self.blop: # pylint: disable=no-member; applies only to this line
    # Here we get an error
    print(self.blip)
else:
    # error
    print(self.blip)

Here's an example with all these rules in a single place:

"""pylint option block-disable"""

__revision__ = None

class Foo(object):
    """block-disable test"""

    def __init__(self):
        pass

    def meth1(self, arg):
        """this issues a message"""
        print(self)

    def meth2(self, arg):
        """and this one not"""
        # pylint: disable=unused-argument
        print(self\
              + "foo")

    def meth3(self):
        """test one line disabling"""
        # no error
        print(self.bla) # pylint: disable=no-member
        # error
        print(self.blop)

    def meth4(self):
        """test re-enabling"""
        # pylint: disable=no-member
        # no error
        print(self.bla)
        print(self.blop)
        # pylint: enable=no-member
        # error
        print(self.blip)

    def meth5(self):
        """test IF sub-block re-enabling"""
        # pylint: disable=no-member
        # no error
        print(self.bla)
        if self.blop:
            # pylint: enable=no-member
            # error
            print(self.blip)
        else:
            # no error
            print(self.blip)
        # no error
        print(self.blip)

    def meth6(self):
        """test TRY/EXCEPT sub-block re-enabling"""
        # pylint: disable=no-member
        # no error
        print(self.bla)
        try:
            # pylint: enable=no-member
            # error
            print(self.blip)
        except UndefinedName: # pylint: disable=undefined-variable
            # no error
            print(self.blip)
        # no error
        print(self.blip)

    def meth7(self):
        """test one line block opening disabling"""
        if self.blop: # pylint: disable=no-member
            # error
            print(self.blip)
        else:
            # error
            print(self.blip)
        # error
        print(self.blip)

    def meth8(self):
        """test late disabling"""
        # error
        print(self.blip)
        # pylint: disable=no-member
        # no error
        print(self.bla)
        print(self.blop)

    def meth9(self):
        """test next line disabling"""
        # no error
        # pylint: disable-next=no-member
        print(self.bla)
        # error
        print(self.blop)

Detecting useless disables

As pylint gets better and false positives are removed, disables that became useless can accumulate and clutter the code. In order to clean them you can enable the useless-suppression warning.