brackets.py

# Copyright (C) 2016 Adrien Vergé
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""
Use this rule to control the use of flow sequences or the number of spaces
inside brackets (``[`` and ``]``).

.. rubric:: Options

* ``forbid`` is used to forbid the use of flow sequences which are denoted by
  surrounding brackets (``[`` and ``]``). Use ``true`` to forbid the use of
  flow sequences completely. Use ``non-empty`` to forbid the use of all flow
  sequences except for empty ones.
* ``min-spaces-inside`` defines the minimal number of spaces required inside
  brackets.
* ``max-spaces-inside`` defines the maximal number of spaces allowed inside
  brackets.
* ``min-spaces-inside-empty`` defines the minimal number of spaces required
  inside empty brackets.
* ``max-spaces-inside-empty`` defines the maximal number of spaces allowed
  inside empty brackets.

.. rubric:: Default values (when enabled)

.. code-block:: yaml

 rules:
   brackets:
     forbid: false
     min-spaces-inside: 0
     max-spaces-inside: 0
     min-spaces-inside-empty: -1
     max-spaces-inside-empty: -1

.. rubric:: Examples

#. With ``brackets: {forbid: true}``

   the following code snippet would **PASS**:
   ::

    object:
      - 1
      - 2
      - abc

   the following code snippet would **FAIL**:
   ::

    object: [ 1, 2, abc ]

#. With ``brackets: {forbid: non-empty}``

   the following code snippet would **PASS**:
   ::

    object: []

   the following code snippet would **FAIL**:
   ::

    object: [ 1, 2, abc ]

#. With ``brackets: {min-spaces-inside: 0, max-spaces-inside: 0}``

   the following code snippet would **PASS**:
   ::

    object: [1, 2, abc]

   the following code snippet would **FAIL**:
   ::

    object: [ 1, 2, abc ]

#. With ``brackets: {min-spaces-inside: 1, max-spaces-inside: 3}``

   the following code snippet would **PASS**:
   ::

    object: [ 1, 2, abc ]

   the following code snippet would **PASS**:
   ::

    object: [ 1, 2, abc   ]

   the following code snippet would **FAIL**:
   ::

    object: [    1, 2, abc   ]

   the following code snippet would **FAIL**:
   ::

    object: [1, 2, abc ]

#. With ``brackets: {min-spaces-inside-empty: 0, max-spaces-inside-empty: 0}``

   the following code snippet would **PASS**:
   ::

    object: []

   the following code snippet would **FAIL**:
   ::

    object: [ ]

#. With ``brackets: {min-spaces-inside-empty: 1, max-spaces-inside-empty: -1}``

   the following code snippet would **PASS**:
   ::

    object: [         ]

   the following code snippet would **FAIL**:
   ::

    object: []
"""


import yaml

from yamllint.linter import LintProblem
from yamllint.rules.common import spaces_after, spaces_before


ID = 'brackets'
TYPE = 'token'
CONF = {'forbid': (bool, 'non-empty'),
        'min-spaces-inside': int,
        'max-spaces-inside': int,
        'min-spaces-inside-empty': int,
        'max-spaces-inside-empty': int}
DEFAULT = {'forbid': False,
           'min-spaces-inside': 0,
           'max-spaces-inside': 0,
           'min-spaces-inside-empty': -1,
           'max-spaces-inside-empty': -1}


def check(conf, token, prev, next, nextnext, context):
    if (conf['forbid'] is True and
            isinstance(token, yaml.FlowSequenceStartToken)):
        yield LintProblem(token.start_mark.line + 1,
                          token.end_mark.column + 1,
                          'forbidden flow sequence')

    elif (conf['forbid'] == 'non-empty' and
            isinstance(token, yaml.FlowSequenceStartToken) and
            not isinstance(next, yaml.FlowSequenceEndToken)):
        yield LintProblem(token.start_mark.line + 1,
                          token.end_mark.column + 1,
                          'forbidden flow sequence')

    elif (isinstance(token, yaml.FlowSequenceStartToken) and
            isinstance(next, yaml.FlowSequenceEndToken)):
        problem = spaces_after(token, prev, next,
                               min=(conf['min-spaces-inside-empty']
                                    if conf['min-spaces-inside-empty'] != -1
                                    else conf['min-spaces-inside']),
                               max=(conf['max-spaces-inside-empty']
                                    if conf['max-spaces-inside-empty'] != -1
                                    else conf['max-spaces-inside']),
                               min_desc='too few spaces inside empty brackets',
                               max_desc=('too many spaces inside empty '
                                         'brackets'))
        if problem is not None:
            yield problem

    elif isinstance(token, yaml.FlowSequenceStartToken):
        problem = spaces_after(token, prev, next,
                               min=conf['min-spaces-inside'],
                               max=conf['max-spaces-inside'],
                               min_desc='too few spaces inside brackets',
                               max_desc='too many spaces inside brackets')
        if problem is not None:
            yield problem

    elif (isinstance(token, yaml.FlowSequenceEndToken) and
            (prev is None or
             not isinstance(prev, yaml.FlowSequenceStartToken))):
        problem = spaces_before(token, prev, next,
                                min=conf['min-spaces-inside'],
                                max=conf['max-spaces-inside'],
                                min_desc='too few spaces inside brackets',
                                max_desc='too many spaces inside brackets')
        if problem is not None:
            yield problem