Pylint output
-------------

Output options
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Output by default is written to stdout. The simplest way to output to a file is
with the ``--output=<filename>`` option.

The default format for the output is raw text. You can change this by passing
pylint the ``--output-format=<value>`` option. Possible values are: ``text``, ``json``,
``parseable``, ``colorized`` and ``msvs`` (for Visual Studio).

Multiple output formats can be used at the same time by passing
a comma-separated list of formats to ``--output-format``.
This output can be redirected to a file by giving a filename after a colon.

For example, to save a json report to ``somefile.json`` and print
a colorized report to stdout at the same time:
::

  --output-format=json:somefile.json,colorized


Custom message formats
''''''''''''''''''''''''''''

You can customize the exact way information are displayed using the
`--msg-template=<format string>` option. The `format string` uses the
`Python new format syntax`_ and the following fields are available :

path
    relative path to the file
abspath
    absolute path to the file
line
    line number
column
    column number
end_line
    line number of the end of the node
end_column
    column number of the end of the node
module
    module name
obj
    object within the module (if any)
msg
    text of the message
msg_id
    the message code (eg. I0011)
symbol
    symbolic name of the message (eg. locally-disabled)
C
    one letter indication of the message category
category
    fullname of the message category

For example, the former (pre 1.0) default format can be obtained with::

  pylint --msg-template='{msg_id}:{line:3d},{column}: {obj}: {msg}'

A few other examples:

* the default format::

    {path}:{line}:{column}: {msg_id}: {msg} ({symbol})

* Visual Studio compatible format (former 'msvs' output format)::

    {path}({line}): [{msg_id}{obj}] {msg}

* Parseable (Emacs and all, former 'parseable' output format) format::

    {path}:{line}: [{msg_id}({symbol}), {obj}] {msg}

The ``--msg-template`` option can only be combined with text-based reporters (``--output-format`` either unspecified or one of: parseable, colorized or msvs).
If both ``--output-format`` and ``--msg-template`` are specified, the ``--msg-template`` option will take precedence over the default line format defined by the reporter class.

If ``end_line`` or ``end_column`` are ``None``, they will be represented as an empty string
by the default ``TextReporter``.

.. _Python new format syntax: https://docs.python.org/2/library/string.html#formatstrings

Source code analysis section
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For each python module, Pylint will first display a few '*' characters followed
by the name of the module. Then, a number of messages with the following format:
::

  MESSAGE_TYPE: LINE_NUM:[OBJECT:] MESSAGE

You can get another output format, useful since it's recognized by
most editors or other development tools using the ``--output-format=parseable``
option.

The message type can be:

  * [I]nformational messages that Pylint emits (do not contribute to your analysis score)
  * [R]efactor for a "good practice" metric violation
  * [C]onvention for coding standard violation
  * [W]arning for stylistic problems, or minor programming issues
  * [E]rror for important programming issues (i.e. most probably bug)
  * [F]atal for errors which prevented further processing

Sometimes the line of code which caused the error is displayed with
a caret pointing to the error. This may be generalized in future
versions of Pylint.

Example (extracted from a run of Pylint on itself...):

::

  ************* Module pylint.checkers.format
  W: 50: Too long line (86/80)
  W:108: Operator not followed by a space
       print >>sys.stderr, 'Unable to match %r', line
              ^
  W:141: Too long line (81/80)
  W: 74:searchall: Unreachable code
  W:171:FormatChecker.process_tokens: Redefining built-in (type)
  W:150:FormatChecker.process_tokens: Too many local variables (20/15)
  W:150:FormatChecker.process_tokens: Too many branches (13/12)


Reports section
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Following the analysis message, Pylint can display a set of reports,
each one focusing on a particular aspect of the project, such as number
of messages by categories, modules dependencies. These features can
be enabled through the ``--reports=y`` option, or its shorthand
version ``-rn``.

For instance, the metrics report displays summaries gathered from the
current run.

  * the number of processed modules
  * for each module, the percentage of errors and warnings
  * the total number of errors and warnings
  * percentage of classes, functions and modules with docstrings, and
    a comparison from the previous run
  * percentage of classes, functions and modules with correct name
    (according to the coding standard), and a comparison from the
    previous run
  * a list of external dependencies found in the code, and where they appear

Score section
'''''''''''''

Finally, Pylint displays a global evaluation score for the code, rated out of a
maximum score of 10.0. This output can be suppressed through the ``--score=n``
option, or its shorthand version ``-sn``.

The evaluation formula can be overridden with the
``--evaluation=<python_expression>`` option.