Add pylint to depot_tools.

third_party/pylint/epylint.py

Index: third_party/pylint/epylint.py
diff --git a/third_party/pylint/epylint.py b/third_party/pylint/epylint.py
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+++ b/third_party/pylint/epylint.py
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+#!/usr/bin/env python
+# -*- coding: utf-8; mode: python; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- vim:fenc=utf-8:ft=python:et:sw=4:ts=4:sts=4
+"""Emacs and Flymake compatible Pylint.
+
+This script is for integration with emacs and is compatible with flymake mode.
+
+epylint walks out of python packages before invoking pylint. This avoids
+reporting import errors that occur when a module within a package uses the
+absolute import path to get another module within this package.
+
+For example:
+    - Suppose a package is structured as
+
+        a/__init__.py
+        a/b/x.py
+        a/c/y.py
+
+   - Then if y.py imports x as "from a.b import x" the following produces pylint errors
+
+       cd a/c; pylint y.py
+
+   - The following obviously doesn't
+
+       pylint a/c/y.py
+
+   - As this script will be invoked by emacs within the directory of the file
+     we are checking we need to go out of it to avoid these false positives.
+
+
+You may also use py_run to run pylint with desired options and get back (or not) its output.
+"""
+
+import sys, os, re
+from subprocess import Popen, PIPE
+
+
+def lint(filename):
+    """Pylint the given file.
+
+    When run from emacs we will be in the directory of a file, and passed its filename.
+    If this file is part of a package and is trying to import other modules from within
+    its own package or another package rooted in a directory below it, pylint will classify
+    it as a failed import.
+
+    To get around this, we traverse down the directory tree to find the root of the package this
+    module is in.  We then invoke pylint from this directory.
+
+    Finally, we must correct the filenames in the output generated by pylint so Emacs doesn't
+    become confused (it will expect just the original filename, while pylint may extend it with
+    extra directories if we've traversed down the tree)
+    """
+    # traverse downwards until we are out of a python package
+    fullPath = os.path.abspath(filename)
+    parentPath, childPath = os.path.dirname(fullPath), os.path.basename(fullPath)
+
+    while parentPath != "/" and os.path.exists(os.path.join(parentPath, '__init__.py')):
+        childPath = os.path.join(os.path.basename(parentPath), childPath)
+        parentPath = os.path.dirname(parentPath)
+
+    # Start pylint
+    process = Popen('pylint -f parseable -r n --disable=C,R,I "%s"' %
+                    childPath, shell=True, stdout=PIPE, stderr=PIPE,
+                    cwd=parentPath)
+    p = process.stdout
+
+    # The parseable line format is '%(path)s:%(line)s: [%(sigle)s%(obj)s] %(msg)s'
+    # NOTE: This would be cleaner if we added an Emacs reporter to pylint.reporters.text ..
+    regex = re.compile(r"\[(?P<type>[WE])(?P<remainder>.*?)\]")
+
+    def _replacement(mObj):
+        "Alter to include 'Error' or 'Warning'"
+        if mObj.group("type") == "W":
+            replacement = "Warning"
+        else:
+            replacement = "Error"
+        # replace as "Warning (W0511, funcName): Warning Text"
+        return "%s (%s%s):" % (replacement, mObj.group("type"), mObj.group("remainder"))
+
+    for line in p:
+        # remove pylintrc warning
+        if line.startswith("No config file found"):
+            continue
+        line = regex.sub(_replacement, line, 1)
+        # modify the file name thats output to reverse the path traversal we made
+        parts = line.split(":")
+        if parts and parts[0] == childPath:
+            line = ":".join([filename] + parts[1:])
+        print line,
+
+    p.close()
+
+def Run():
+    lint(sys.argv[1])
+
+
+def py_run(command_options='', return_std=False, stdout=None, stderr=None,
+           script='epylint'):
+    """Run pylint from python (needs Python >= 2.4).
+
+    ``command_options`` is a string containing ``pylint`` command line options;
+    ``return_std`` (boolean) indicates return of created standart output
+    and error (see below);
+    ``stdout`` and ``stderr`` are 'file-like' objects in which standart output
+    could be written.
+
+    Calling agent is responsible for stdout/err management (creation, close).
+    Default standart output and error are those from sys,
+    or standalone ones (``subprocess.PIPE``) are used
+    if they are not set and ``return_std``.
+
+    If ``return_std`` is set to ``True``, this function returns a 2-uple
+    containing standart output and error related to created process,
+    as follows: ``(stdout, stderr)``.
+
+    A trivial usage could be as follows:
+        >>> py_run( '--version')
+        No config file found, using default configuration
+        pylint 0.18.1,
+            ...
+
+    To silently run Pylint on a module, and get its standart output and error:
+        >>> (pylint_stdout, pylint_stderr) = py_run( 'module_name.py', True)
+    """
+    # Create command line to call pylint
+    if os.name == 'nt':
+        script += '.bat'
+    command_line = script + ' ' + command_options
+    # Providing standart output and/or error if not set
+    if stdout is None:
+        if return_std:
+            stdout = PIPE
+        else:
+            stdout = sys.stdout
+    if stderr is None:
+        if return_std:
+            stderr = PIPE
+        else:
+            stderr = sys.stderr
+    # Call pylint in a subprocess
+    p = Popen(command_line, shell=True, stdout=stdout, stderr=stderr)
+    p.wait()
+    # Return standart output and error
+    if return_std:
+        return (p.stdout, p.stderr)
+
+
+if __name__ == '__main__':
+    lint(sys.argv[1])
+