DevTools: Add lint_javascript.py to drive eslint

third_party/WebKit/Source/devtools/scripts/lint_javascript.py

Index: third_party/WebKit/Source/devtools/scripts/lint_javascript.py
diff --git a/third_party/WebKit/Source/devtools/scripts/lint_javascript.py b/third_party/WebKit/Source/devtools/scripts/lint_javascript.py
new file mode 100755
index 0000000000000000000000000000000000000000..5f39b857e78859385c470a346efc1990c6d283c9
--- /dev/null
+++ b/third_party/WebKit/Source/devtools/scripts/lint_javascript.py
@@ -0,0 +1,133 @@
+#!/usr/bin/env python
+# Copyright (c) 2012 Google Inc. All rights reserved.

[caseq, 2016/04/26 01:39:44]

Let's bring the 3-line chromium authors copyright?

[paulirish, 2016/04/26 03:37:43]

done

+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import os
+import os.path as path
+import re
+import subprocess
+import sys
+
+files_to_lint = None
+
+if len(sys.argv) == 2:
+    if sys.argv[1] == '--help':

[caseq, 2016/04/26 01:39:44]

Let's settle on one quote style? Either is good per code style, but I guess we
could make it double quotes for consistency with JS.

[paulirish, 2016/04/26 03:37:43]

double. you got it.

+        print("Usage: %s [file|dir|glob]*" % path.basename(sys.argv[0]))
+        print
+        print(" [file|dir|glob]*  Path or glob to run eslint on.")
+        print("                   If absent, the entire frontend will be checked.")
+        sys.exit(0)
+
+    else:
+        print 'Linting only this path:\n %s' % sys.argv[1:]
+        files_to_lint = sys.argv[1:]
+
+
+is_cygwin = sys.platform == 'cygwin'
+
+
+def popen(arguments):
+    return subprocess.Popen(arguments, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+
+
+def to_platform_path(filepath):
+    if not is_cygwin:
+        return filepath
+    return re.sub(r'^/cygdrive/(\w)', '\\1:', filepath)
+
+
+def to_platform_path_exact(filepath):
+    if not is_cygwin:
+        return filepath
+    output, _ = popen(['cygpath', '-w', filepath]).communicate()
+    # pylint: disable=E1103
+    return output.strip().replace('\\', '\\\\')
+
+scripts_path = path.dirname(path.abspath(__file__))
+devtools_path = path.dirname(scripts_path)
+devtools_frontend_path = path.join(devtools_path, 'front_end')
+
+
+# Based on http://stackoverflow.com/questions/377017/test-if-executable-exists-in-python.
+def which(program):
+    def is_exe(fpath):
+        return path.isfile(fpath) and os.access(fpath, os.X_OK)
+
+    fpath, fname = path.split(program)
+    if fpath:
+        if is_exe(program):
+            return program
+    else:
+        for part in os.environ["PATH"].split(os.pathsep):
+            part = part.strip('"')
+            exe_file = path.join(part, program)
+            if is_exe(exe_file):
+                return exe_file
+    return None
+
+
+print 'Linting JavaScript with eslint...\n'
+errors_found = False

[caseq, 2016/04/26 01:39:44]

move into js_lint?

[paulirish, 2016/04/26 03:37:43]

Seems good. done.

+
+
+def js_lint(files_list=None):
+    eslint_path = which('eslint')
+    if not eslint_path:
+        print '!! Skipping JavaScript linting because eslint is not installed.'
+        print '!!   npm install -g eslint'
+        errors_found = False  # Linting is opt-in for now, so this is a soft failure
+        return errors_found
+
+    if files_list is None:
+        files_list = [devtools_frontend_path]
+
+    eslintconfig_path = path.join(devtools_path, 'front_end/.eslintrc.js')
+    eslintignore_path = path.join(devtools_path, 'front_end/.eslintignore')
+    exec_command = [
+        eslint_path,
+        '--config', to_platform_path_exact(eslintconfig_path),
+        '--ignore-path', to_platform_path_exact(eslintignore_path),
+        ' '.join(files_list)
+        ]
+
+    eslint_proc = popen(exec_command)
+    (eslint_proc_out, _) = eslint_proc.communicate()
+    if eslint_proc.returncode != 0:
+        errors_found = True
+        print eslint_proc_out

[caseq, 2016/04/26 01:39:44]

move out of conditional?

[paulirish, 2016/04/26 03:37:43]

done

+    else:
+        print 'eslint exited successfully'
+        print eslint_proc_out
+
+    return errors_found
+
+errors_found = js_lint(files_to_lint)
+
+if errors_found:
+    print 'ERRORS DETECTED'
+    sys.exit(1)