1 files changed, 195 insertions, 0 deletions
diff --git a/tools/lint/flake8.lint b/tools/lint/flake8.lint
new file mode 100644
index 000000000..eaf4a4dff
--- /dev/null
+++ b/tools/lint/flake8.lint
@@ -0,0 +1,195 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import json
+import os
+import signal
+import subprocess
+
+import which
+from mozprocess import ProcessHandler
+
+from mozlint import result
+
+
+here = os.path.abspath(os.path.dirname(__file__))
+FLAKE8_REQUIREMENTS_PATH = os.path.join(here, 'flake8', 'flake8_requirements.txt')
+
+FLAKE8_NOT_FOUND = """
+Could not find flake8! Install flake8 and try again.
+
+    $ pip install -U --require-hashes -r {}
+""".strip().format(FLAKE8_REQUIREMENTS_PATH)
+
+
+FLAKE8_INSTALL_ERROR = """
+Unable to install correct version of flake8
+Try to install it manually with:
+    $ pip install -U --require-hashes -r {}
+""".strip().format(FLAKE8_REQUIREMENTS_PATH)
+
+LINE_OFFSETS = {
+    # continuation line under-indented for hanging indent
+    'E121': (-1, 2),
+    # continuation line missing indentation or outdented
+    'E122': (-1, 2),
+    # continuation line over-indented for hanging indent
+    'E126': (-1, 2),
+    # continuation line over-indented for visual indent
+    'E127': (-1, 2),
+    # continuation line under-indented for visual indent
+    'E128': (-1, 2),
+    # continuation line unaligned for hanging indend
+    'E131': (-1, 2),
+    # expected 1 blank line, found 0
+    'E301': (-1, 2),
+    # expected 2 blank lines, found 1
+    'E302': (-2, 3),
+}
+"""Maps a flake8 error to a lineoffset tuple.
+
+The offset is of the form (lineno_offset, num_lines) and is passed
+to the lineoffset property of `ResultContainer`.
+"""
+
+EXTENSIONS = ['.py', '.lint']
+results = []
+
+
+def process_line(line):
+    # Escape slashes otherwise JSON conversion will not work
+    line = line.replace('\\', '\\\\')
+    try:
+        res = json.loads(line)
+    except ValueError:
+        print('Non JSON output from linter, will not be processed: {}'.format(line))
+        return
+
+    if 'code' in res:
+        if res['code'].startswith('W'):
+            res['level'] = 'warning'
+
+        if res['code'] in LINE_OFFSETS:
+            res['lineoffset'] = LINE_OFFSETS[res['code']]
+
+    results.append(result.from_linter(LINTER, **res))
+
+
+def run_process(cmdargs):
+    # flake8 seems to handle SIGINT poorly. Handle it here instead
+    # so we can kill the process without a cryptic traceback.
+    orig = signal.signal(signal.SIGINT, signal.SIG_IGN)
+    proc = ProcessHandler(cmdargs, env=os.environ,
+                          processOutputLine=process_line)
+    proc.run()
+    signal.signal(signal.SIGINT, orig)
+
+    try:
+        proc.wait()
+    except KeyboardInterrupt:
+        proc.kill()
+
+
+def get_flake8_binary():
+    """
+    Returns the path of the first flake8 binary available
+    if not found returns None
+    """
+    binary = os.environ.get('FLAKE8')
+    if binary:
+        return binary
+
+    try:
+        return which.which('flake8')
+    except which.WhichError:
+        return None
+
+
+def _run_pip(*args):
+    """
+    Helper function that runs pip with subprocess
+    """
+    try:
+        subprocess.check_output(['pip'] + list(args),
+                                      stderr=subprocess.STDOUT)
+        return True
+    except subprocess.CalledProcessError as e:
+        print(e.output)
+        return False
+
+
+def reinstall_flake8():
+    """
+    Try to install flake8 at the target version, returns True on success
+    otherwise prints the otuput of the pip command and returns False
+    """
+    if _run_pip('install', '-U',
+                '--require-hashes', '-r',
+                FLAKE8_REQUIREMENTS_PATH):
+        return True
+
+    return False
+
+
+def lint(files, **lintargs):
+
+    if not reinstall_flake8():
+        print(FLAKE8_INSTALL_ERROR)
+        return 1
+
+    binary = get_flake8_binary()
+
+    cmdargs = [
+        binary,
+        '--format', '{"path":"%(path)s","lineno":%(row)s,'
+                    '"column":%(col)s,"rule":"%(code)s","message":"%(text)s"}',
+    ]
+
+    # Run any paths with a .flake8 file in the directory separately so
+    # it gets picked up. This means only .flake8 files that live in
+    # directories that are explicitly included will be considered.
+    # See bug 1277851
+    no_config = []
+    for f in files:
+        if not os.path.isfile(os.path.join(f, '.flake8')):
+            no_config.append(f)
+            continue
+        run_process(cmdargs+[f])
+
+    # XXX For some reason passing in --exclude results in flake8 not using
+    # the local .flake8 file. So for now only pass in --exclude if there
+    # is no local config.
+    exclude = lintargs.get('exclude')
+    if exclude:
+        cmdargs += ['--exclude', ','.join(lintargs['exclude'])]
+
+    if no_config:
+        run_process(cmdargs+no_config)
+
+    return results
+
+
+LINTER = {
+    'name': "flake8",
+    'description': "Python linter",
+    'include': [
+        'python/mozlint',
+        'taskcluster',
+        'testing/firefox-ui',
+        'testing/marionette/client',
+        'testing/marionette/harness',
+        'testing/marionette/puppeteer',
+        'testing/mozbase',
+        'testing/mochitest',
+        'testing/talos/',
+        'tools/lint',
+    ],
+    'exclude': ["testing/mozbase/mozdevice/mozdevice/Zeroconf.py",
+                'testing/mochitest/pywebsocket'],
+    'extensions': EXTENSIONS,
+    'type': 'external',
+    'payload': lint,
+}