Use pylint.

18 files changed, 93 insertions, 53 deletions

diff --git a/build_extra/rust/get_rustc_info.py b/build_extra/rust/get_rustc_info.py
index 1b61bdbc0..66751c20b 100755
--- a/build_extra/rust/get_rustc_info.py
+++ b/build_extra/rust/get_rustc_info.py
@@ -48,7 +48,7 @@ def get_ldflags(rustc_args):
     # On Posix systems, this file is directly executable thanks to it's shebang.
     # On Windows, we use a .cmd wrapper file.
     if os.name == "nt":
-        rustc_linker_base, rustc_linker_ext = path.splitext(__file__)
+        rustc_linker_base, _rustc_linker_ext = path.splitext(__file__)
         rustc_linker = rustc_linker_base + ".cmd"
     else:
         rustc_linker = __file__
diff --git a/tools/benchmark.py b/tools/benchmark.py
index 760bad100..fe71cc88e 100755
--- a/tools/benchmark.py
+++ b/tools/benchmark.py
@@ -1,7 +1,8 @@
 #!/usr/bin/env python
 # Copyright 2018 the Deno authors. All rights reserved. MIT license.
 # Performs benchmark and append data to //website/data.json.
-# If //website/data.json doesn't exist, this script tries to import it from gh-pages branch.
+# If //website/data.json doesn't exist, this script tries to import it from
+# gh-pages branch.
 # To view the results locally run ./tools/http_server.py and visit
 # http://localhost:4545/website
 
@@ -49,7 +50,7 @@ def import_data_from_gh_pages():
             "https://github.com/denoland/deno.git", "gh-pages"
         ])
         shutil.copy(gh_pages_data_file, all_data_file)
-    except:
+    except ValueError:
         write_json(all_data_file, [])  # writes empty json data
 
 
diff --git a/tools/deno_dir_test.py b/tools/deno_dir_test.py
index bb07b7544..9f53cf3b9 100755
--- a/tools/deno_dir_test.py
+++ b/tools/deno_dir_test.py
@@ -40,9 +40,12 @@ def run_deno(deno_exe, deno_dir=None):
     run(cmd, quiet=True, env=deno_dir_env)
 
 
+USAGE = "./tools/deno_dir_test.py target/debug/deno target/debug/.deno_dir"
+
+
 def main(argv):
     if len(sys.argv) != 3:
-        print "Usage ./tools/deno_dir_test.py target/debug/deno target/debug/.deno_dir"
+        print "Usage: " + USAGE
         sys.exit(1)
     deno_dir_test(argv[1], argv[2])
 
diff --git a/tools/gcloud_upload.py b/tools/gcloud_upload.py
index ed9c48ec8..b919a1ed9 100755
--- a/tools/gcloud_upload.py
+++ b/tools/gcloud_upload.py
@@ -14,7 +14,7 @@ from third_party import tp
 
 
 def print_usage():
-    print "Usage: ./tools/gcloud_upload.py target/release/obj/third_party/v8/libv8.a"
+    print "Usage: ./tools/gcloud_upload.py target/release/libv8.a"
     sys.exit(1)
 
 
diff --git a/tools/http_server.py b/tools/http_server.py
index 065635c6f..f9820ff19 100755
--- a/tools/http_server.py
+++ b/tools/http_server.py
@@ -62,7 +62,7 @@ def redirect_server():
     Handler = RedirectHandler
     SocketServer.TCPServer.allow_reuse_address = True
     s = SocketServer.TCPServer(("", REDIRECT_PORT), Handler)
-    print "Deno redirect server http://localhost:%d/ -> http://localhost:%d/" % (
+    print "redirect server http://localhost:%d/ -> http://localhost:%d/" % (
         REDIRECT_PORT, PORT)
     return s
 
@@ -82,7 +82,7 @@ def spawn():
     return thread
 
 
-if __name__ == '__main__':
+def main():
     try:
         thread = spawn()
         while thread.is_alive():
@@ -90,3 +90,7 @@ if __name__ == '__main__':
     except KeyboardInterrupt:
         pass
     sys.exit(1)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/tools/lint.py b/tools/lint.py
index f163a3264..e297c0478 100755
--- a/tools/lint.py
+++ b/tools/lint.py
@@ -3,7 +3,8 @@
 # Does google-lint on c++ files and ts-lint on typescript files
 
 import os
-from util import enable_ansi_colors, run
+import sys
+from util import enable_ansi_colors, run, find_exts
 
 enable_ansi_colors()
 
@@ -24,3 +25,6 @@ run([
     "node", tslint, "./js/**/*_test.ts", "./tests/**/*.ts", "--exclude",
     "**/gen/**/*.ts", "--project", "tsconfig.json"
 ])
+
+run([sys.executable, "third_party/depot_tools/pylint.py"] +
+    find_exts(["tools", "build_extra"], [".py"], skip=["tools/clang"]))
diff --git a/tools/permission_prompt_test.py b/tools/permission_prompt_test.py
index 2bc24d12c..7f0ae1c97 100755
--- a/tools/permission_prompt_test.py
+++ b/tools/permission_prompt_test.py
@@ -138,6 +138,10 @@ def permission_prompt_test(deno_exe):
     p.test_net_no()
 
 
-if __name__ == "__main__":
+def main():
     deno_exe = os.path.join(build_path(), "deno" + executable_suffix)
     permission_prompt_test(deno_exe)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tools/repl_test.py b/tools/repl_test.py
index ce3db8953..afce192f5 100644
--- a/tools/repl_test.py
+++ b/tools/repl_test.py
@@ -35,7 +35,7 @@ class Repl(object):
         except CalledProcessError as e:
             p.kill()
             p.wait()
-            raise
+            raise e
         retcode = p.poll()
         # Ignore Windows CRLF (\r\n).
         return out.replace('\r\n', '\n'), err.replace('\r\n', '\n'), retcode
@@ -125,6 +125,10 @@ def repl_tests(deno_exe):
     Repl(deno_exe).run()
 
 
-if __name__ == "__main__":
+def main():
     deno_exe = os.path.join(build_path(), "deno" + executable_suffix)
     repl_tests(deno_exe)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tools/setup.py b/tools/setup.py
index 44c183553..8660ee6d7 100755
--- a/tools/setup.py
+++ b/tools/setup.py
@@ -94,9 +94,9 @@ def write_gn_args(args_filename, args):
     assert gn_args_are_generated(lines)  # With header -> generated.
 
     # Ensure the directory where args.gn goes exists.
-    dir = os.path.dirname(args_filename)
-    if not os.path.isdir(dir):
-        os.makedirs(dir)
+    d = os.path.dirname(args_filename)
+    if not os.path.isdir(d):
+        os.makedirs(d)
 
     with open(args_filename, "w") as f:
         f.write("\n".join(lines) + "\n")
diff --git a/tools/setup_test.py b/tools/setup_test.py
index 15dff00fa..bc0a9ecba 100644
--- a/tools/setup_test.py
+++ b/tools/setup_test.py
@@ -40,22 +40,22 @@ def read_gn_args_test():
 
 def write_gn_args_test():
     # Build a nonexistent path; write_gn_args() should call mkdir as needed.
-    dir = mktemp()
-    filename = os.path.join(dir, "args.gn")
-    assert not os.path.exists(dir)
+    d = mktemp()
+    filename = os.path.join(d, "args.gn")
+    assert not os.path.exists(d)
     assert not os.path.exists(filename)
     # Write some args.
     args = ['lalala=42', 'foo_bar_baz="lorem ipsum dolor#amet"']
     write_gn_args(filename, args)
     # Directory and args file should now be created.
-    assert os.path.isdir(dir)
+    assert os.path.isdir(d)
     assert os.path.isfile(filename)
     # Validate that the right contents were written.
     (check_args, hand_edited) = read_gn_args(filename)
     assert check_args == args
     assert hand_edited == False
     # Clean up.
-    rmtree(dir)
+    rmtree(d)
 
 
 def setup_test():
diff --git a/tools/sha256sum.py b/tools/sha256sum.py
index d3273d5ba..139368e89 100644
--- a/tools/sha256sum.py
+++ b/tools/sha256sum.py
@@ -55,15 +55,15 @@ def main():
     hasher = sha256()
     for data in args.input:
         hasher.update(data)
-    hash = hasher.hexdigest()
+    h = hasher.hexdigest()
 
     # Format and write to specified out file (or the default, stdout).
-    args.outfile.write(args.format % hash)
+    args.outfile.write(args.format % h)
 
 
 def read_file(filename):
-    with open(filename, "rb") as file:
-        return file.read()
+    with open(filename, "rb") as f:
+        return f.read()
 
 
 if __name__ == '__main__':
diff --git a/tools/sync_third_party.py b/tools/sync_third_party.py
index 5fe78c407..4205c4883 100755
--- a/tools/sync_third_party.py
+++ b/tools/sync_third_party.py
@@ -3,7 +3,8 @@
 # Run this script if you are changing Deno's dependencies.
 # To update the deno_third_party git repo after running this, try the following:
 # cd third_party
-# find . -type f | grep -v "\.git" | xargs -I% git add -f --no-warn-embedded-repo "%"
+# find . -type f | grep -v "\.git" | \
+#   xargs -I% git add -f --no-warn-embedded-repo "%"
 
 import third_party
 import util
diff --git a/tools/test_format.py b/tools/test_format.py
index 5e93286b6..a0d5ba08e 100755
--- a/tools/test_format.py
+++ b/tools/test_format.py
@@ -7,7 +7,7 @@ import sys
 import subprocess
 
 
-def main(argv):
+def main():
     util.run([sys.executable, "tools/format.py"])
     output = util.run_output(
         ["git", "status", "-uno", "--porcelain", "--ignore-submodules"])
@@ -18,4 +18,4 @@ def main(argv):
 
 
 if __name__ == '__main__':
-    main(sys.argv)
+    main()
diff --git a/tools/third_party.py b/tools/third_party.py
index 46a9cf82e..d7b587845 100644
--- a/tools/third_party.py
+++ b/tools/third_party.py
@@ -34,7 +34,9 @@ python_site_env = None
 
 # Creates/modifies an environment so python can find packages that are bundled
 # in the 'third_party' directory.
-def python_env(env=None, merge_env={}, depot_tools_path=depot_tools_path):
+def python_env(env=None, merge_env=None):
+    if merge_env is None:
+        merge_env = {}
     global python_site_env
 
     # Use site.addsitedir() to determine which search paths would be considered
@@ -59,12 +61,14 @@ def python_env(env=None, merge_env={}, depot_tools_path=depot_tools_path):
 
 # This function creates or modifies an environment so that it matches the
 # expectations of various google tools (gn, gclient, etc).
-def google_env(env=None, merge_env={}, depot_tools_path=depot_tools_path):
+def google_env(env=None, merge_env=None, depot_tools_path_=depot_tools_path):
+    if merge_env is None:
+        merge_env = {}
     # Google tools need the python env too.
     env = python_env(env=env, merge_env=merge_env)
 
     # Depot_tools to be in the PATH, before Python.
-    add_env_path(depot_tools_path, env=env, prepend=True)
+    add_env_path(depot_tools_path_, env=env, prepend=True)
 
     if os.name == "nt":  # Windows-only enviroment tweaks.
         # We're not using Google's internal infrastructure.
@@ -89,7 +93,7 @@ def fix_symlinks():
     # Ensure the third_party directory exists.
     try:
         os.makedirs(third_party_path)
-    except:
+    except OSError:
         pass
 
     # Make symlinks to Yarn metadata living in the root repo.
@@ -102,8 +106,8 @@ def fix_symlinks():
     remove_and_symlink("v8/third_party/markupsafe", tp("markupsafe"), True)
 
     # On Windows, git doesn't create the right type of symlink if the symlink
-    # and it's target are in different repos. Here we fix the symlinks that exist
-    # in the root repo while their target is in the third_party repo.
+    # and it's target are in different repos. Here we fix the symlinks that
+    # exist in the root repo while their target is in the third_party repo.
     remove_and_symlink("third_party/node_modules", root("node_modules"), True)
     remove_and_symlink("third_party/v8/buildtools", root("buildtools"), True)
     remove_and_symlink("third_party/v8/build_overrides",
@@ -120,9 +124,9 @@ def run_yarn():
 
 # Run Cargo to install Rust dependencies.
 def run_cargo():
-    # Deletes the cargo index lockfile; it appears that cargo itself doesn't do it.
-    # If the lockfile ends up in the git repo, it'll make cargo hang for everyone
-    # else who tries to run sync_third_party.
+    # Deletes the cargo index lockfile; it appears that cargo itself doesn't do
+    # it.  If the lockfile ends up in the git repo, it'll make cargo hang for
+    # everyone else who tries to run sync_third_party.
     def delete_lockfile():
         lockfiles = find_exts([path.join(rust_crates_path, "registry/index")],
                               ['.cargo-index-lock'])
@@ -186,7 +190,7 @@ def run_gclient_sync():
     # Rename depot_tools to depot_tools_temp.
     try:
         os.rename(depot_tools_path, depot_tools_temp_path)
-    except:
+    except OSError:
         # If renaming failed, and the depot_tools_temp directory already exists,
         # assume that it's still there because a prior run_gclient_sync() call
         # failed half-way, before we got the chance to remove the temp dir.
@@ -204,7 +208,7 @@ def run_gclient_sync():
         'DEPOT_TOOLS_UPDATE': "0",
         'GCLIENT_FILE': root("gclient_config.py")
     }
-    env = google_env(depot_tools_path=depot_tools_temp_path, merge_env=envs)
+    env = google_env(depot_tools_path_=depot_tools_temp_path, merge_env=envs)
     run(args, cwd=third_party_path, env=env)
 
     # Delete the depot_tools_temp directory, but not before verifying that
diff --git a/tools/throughput_benchmark.py b/tools/throughput_benchmark.py
index 457f50bae..7afd3cb81 100755
--- a/tools/throughput_benchmark.py
+++ b/tools/throughput_benchmark.py
@@ -1,7 +1,8 @@
 #!/usr/bin/env python
 # Copyright 2018 the Deno authors. All rights reserved. MIT license.
 # Performs benchmark and append data to //website/data.json.
-# If //website/data.json doesn't exist, this script tries to import it from gh-pages branch.
+# If //website/data.json doesn't exist, this script tries to import it from
+# gh-pages branch.
 # To view the results locally run ./tools/http_server.py and visit
 # http://localhost:4545/website
 
@@ -44,7 +45,7 @@ def tcp(deno_exe, megs):
         echo_server.kill()
 
 
-if __name__ == '__main__':
+def main():
     deno_exe = sys.argv[1]
     megs = int(sys.argv[2])
     if not deno_exe or not megs:
@@ -52,3 +53,7 @@ if __name__ == '__main__':
         sys.exit(1)
     secs = tcp(sys.argv[1], megs)
     print secs, "seconds"
+
+
+if __name__ == '__main__':
+    main()
diff --git a/tools/unit_tests.py b/tools/unit_tests.py
index 47dfcf886..8b36fec44 100755
--- a/tools/unit_tests.py
+++ b/tools/unit_tests.py
@@ -29,7 +29,9 @@ def run_unit_test2(cmd):
         sys.exit(errcode)
 
 
-def run_unit_test(deno_exe, permStr, flags=[]):
+def run_unit_test(deno_exe, permStr, flags=None):
+    if flags is None:
+        flags = []
     cmd = [deno_exe, "--reload", "js/unit_tests.ts", permStr] + flags
     run_unit_test2(cmd)
 
diff --git a/tools/util.py b/tools/util.py
index 8c126bd83..b77f17282 100644
--- a/tools/util.py
+++ b/tools/util.py
@@ -14,10 +14,12 @@ executable_suffix = ".exe" if os.name == "nt" else ""
 root_path = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
 
 
-def make_env(merge_env={}, env=None):
+def make_env(merge_env=None, env=None):
     if env is None:
         env = os.environ
     env = env.copy()
+    if merge_env is None:
+        merge_env = {}
     for key in merge_env.keys():
         env[key] = merge_env[key]
     return env
@@ -25,19 +27,21 @@ def make_env(merge_env={}, env=None):
 
 def add_env_path(add, env, key="PATH", prepend=False):
     dirs_left = env[key].split(os.pathsep) if key in env else []
-    dirs_right = add.split(os.pathsep) if type(add) is str else add
+    dirs_right = add.split(os.pathsep) if isinstance(add, str) else add
 
     if prepend:
         dirs_left, dirs_right = dirs_right, dirs_left
 
-    for dir in dirs_right:
-        if not dir in dirs_left:
-            dirs_left += [dir]
+    for d in dirs_right:
+        if not d in dirs_left:
+            dirs_left += [d]
 
     env[key] = os.pathsep.join(dirs_left)
 
 
-def run(args, quiet=False, cwd=None, env=None, merge_env={}):
+def run(args, quiet=False, cwd=None, env=None, merge_env=None):
+    if merge_env is None:
+        merge_env = {}
     args[0] = os.path.normpath(args[0])
     if not quiet:
         print " ".join(args)
@@ -48,7 +52,9 @@ def run(args, quiet=False, cwd=None, env=None, merge_env={}):
         sys.exit(rc)
 
 
-def run_output(args, quiet=False, cwd=None, env=None, merge_env={}):
+def run_output(args, quiet=False, cwd=None, env=None, merge_env=None):
+    if merge_env is None:
+        merge_env = {}
     args[0] = os.path.normpath(args[0])
     if not quiet:
         print " ".join(args)
@@ -92,7 +98,7 @@ def remove_and_symlink(target, name, target_is_dir=False):
             os.rmdir(name)
         else:
             os.unlink(name)
-    except:
+    except OSError:
         pass
     symlink(target, name, target_is_dir)
 
@@ -146,7 +152,9 @@ def touch(fname):
 #   * Recursive glob doesn't exist in python 2.7.
 #   * On windows, `os.walk()` unconditionally follows symlinks.
 #     The `skip`  parameter should be used to avoid recursing through those.
-def find_exts(directories, extensions, skip=[]):
+def find_exts(directories, extensions, skip=None):
+    if skip is None:
+        skip = []
     assert isinstance(directories, list)
     assert isinstance(extensions, list)
     skip = [os.path.normpath(i) for i in skip]
@@ -247,7 +255,7 @@ def enable_ansi_colors_win10():
 
     # Function factory for errcheck callbacks that raise WinError on failure.
     def raise_if(error_result):
-        def check(result, func, args):
+        def check(result, _func, args):
             if result == error_result:
                 raise ctypes.WinError(ctypes.get_last_error())
             return args
@@ -321,7 +329,7 @@ def enable_ansi_colors_win10():
     # Try to set the flag that controls ANSI escape code support.
     try:
         SetConsoleMode(conout, mode.value | ENABLE_VIRTUAL_TERMINAL_PROCESSING)
-    except WindowsError as e:
+    except WindowsError as e:  # pylint:disable=undefined-variable
         if e.winerror == ERROR_INVALID_PARAMETER:
             return False  # Not supported, likely an older version of Windows.
         raise
@@ -332,7 +340,6 @@ def enable_ansi_colors_win10():
 
 
 def parse_unit_test_output(output, print_to_stdout):
-    first = True
     expected = None
     actual = None
     result = None
diff --git a/tools/util_test.py b/tools/util_test.py
index 24fd2eba1..bf2b92b5a 100644
--- a/tools/util_test.py
+++ b/tools/util_test.py
@@ -21,7 +21,8 @@ def pattern_match_test():
     # Iterate through the fixture lists, testing each one
     for (pattern, string, expected) in fixtures:
         actual = pattern_match(pattern, string)
-        assert expected == actual, "expected %s for\nExpected:\n%s\nTo equal actual:\n%s" % (
+        assert expected == actual, \
+            "expected %s for\nExpected:\n%s\nTo equal actual:\n%s" % (
             expected, pattern, string)
 
     assert pattern_match("foo[BAR]baz", "foobarbaz",