Noissue - Added flake8 extension accounting for our coding style and some other stuff

flake8-abp/flake8_abp.py

Index: flake8-abp/flake8_abp.py
===================================================================
new file mode 100644
--- /dev/null
+++ b/flake8-abp/flake8_abp.py
@@ -0,0 +1,471 @@
+# This file is part of Adblock Plus <https://adblockplus.org/>,
+# Copyright (C) 2006-2016 Eyeo GmbH
+#
+# Adblock Plus is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# Adblock Plus is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+
+import ast
+import re
+import tokenize
+import sys
+import collections
+
+try:
+    import builtins
+except ImportError:
+    import __builtin__ as builtins
+
+import pkg_resources
+
+try:
+    ascii
+except NameError:
+    ascii = repr
+
+__version__ = pkg_resources.get_distribution('flake8-abp').version
+
+DISCOURAGED_APIS = {
+    're.match': 're.search',
+    'codecs.open': 'io.open',
+}
+
+ESSENTIAL_BUILTINS = set(dir(builtins)) - {'apply', 'buffer', 'coerce',
+                                           'intern', 'file'}
+
+LEAVE_BLOCK = (ast.Return, ast.Raise, ast.Continue, ast.Break)
+VOLATILE = object()
+
+
+def evaluate(node):
+    try:
+        return eval(compile(ast.Expression(node), '', 'eval'), {})
+    except Exception:
+        return VOLATILE
+
+
+def is_const(node):
+    return evaluate(node) is not VOLATILE
+
+
+def get_identifier(node):
+    if isinstance(node, ast.Name):
+        return node.id
+    if isinstance(node, ast.Attribute) and isinstance(node.value, ast.Name):
+        return '{}.{}'.format(node.value.id, node.attr)
+
+
+def get_statement(node):
+    return type(node).__name__.lower()
+
+
+class TreeVisitor(ast.NodeVisitor):
+    Scope = collections.namedtuple('Scope', ['node', 'names', 'globals'])
+
+    def __init__(self):
+        self.errors = []
+        self.scope_stack = []
+
+    def _visit_block(self, nodes, block_required=False,
+                     nodes_required=True, docstring=False,
+                     can_have_unused_expr=False):
+        pass_node = None
+        has_non_pass = False
+        leave_node = None
+        dead_code = False
+
+        for i, node in enumerate(nodes):
+            if isinstance(node, ast.Pass):
+                pass_node = node
+            else:
+                has_non_pass = True
+
+            if leave_node and not dead_code:
+                dead_code = True
+                statement = get_statement(leave_node)
+                self.errors.append((node, 'A202 dead code after '
+                                          '{}'.format(statement)))
+
+            if isinstance(node, LEAVE_BLOCK):
+                leave_node = node
+
+            if can_have_unused_expr or not isinstance(node, ast.Expr):
+                continue
+            if docstring and i == 0 and isinstance(node.value, ast.Str):
+                continue
+            if isinstance(node.value, (ast.Call, ast.Yield)):
+                continue
+
+            self.errors.append((node, 'A203 unused expression'))
+
+        if pass_node:
+            if not nodes_required or len(nodes) > 1:
+                self.errors.append((pass_node, 'A204 redundant '
+                                               'pass statement'))
+
+            if not block_required and not has_non_pass:
+                self.errors.append((pass_node, 'A205 empty block'))
+
+    def _check_redundant_else(self, node, handlers, clause):
+        if not node.orelse:
+            return
+
+        for handler in handlers:
+            for child in handler.body:
+                if isinstance(child, LEAVE_BLOCK):
+                    leave_node = child
+                    break
+            else:
+                return
+
+        statement = get_statement(leave_node)
+        self.errors.append((node.orelse[0],
+                            'A206 Extraneous else statement after {} '
+                            'in {}-clause'.format(statement, clause)))
+
+    def visit_If(self, node):
+        self._visit_block(node.body, block_required=bool(node.orelse))
+        self._visit_block(node.orelse)
+        self._check_redundant_else(node, [node], 'if')
+        self.generic_visit(node)
+
+    def visit_Try(self, node):
+        self._visit_block(node.body, can_have_unused_expr=bool(node.handlers))
+        self._visit_block(node.orelse)
+        self._visit_block(node.finalbody)
+        self._check_redundant_else(node, node.handlers, 'except')
+        self.generic_visit(node)
+
+    def visit_TryExcept(self, node):
+        self._visit_block(node.body, can_have_unused_expr=True)
+        self._visit_block(node.orelse)
+        self._check_redundant_else(node, node.handlers, 'except')
+        self.generic_visit(node)
+
+    def visit_TryFinally(self, node):
+        self._visit_block(node.body)
+        self._visit_block(node.finalbody)
+        self.generic_visit(node)
+
+    def visit_ExceptHandler(self, node):
+        self._visit_block(node.body, block_required=True)
+        self.generic_visit(node)
+
+    def _visit_stored_name(self, node, name):
+        scope = self.scope_stack[-1]
+        scope.names.add(name)
+
+        if name in ESSENTIAL_BUILTINS and isinstance(scope.node,
+                                                     ast.FunctionDef):
+            self.errors.append((node, 'A302 redefined built-in ' + name))
+
+    def visit_Name(self, node):
+        if isinstance(node.ctx, (ast.Store, ast.Param)):
+            self._visit_stored_name(node, node.id)
+
+    def visit_arg(self, node):
+        self._visit_stored_name(node, node.arg)
+
+    def _visit_with_scope(self, node):
+        scope = self.Scope(node, names=set(), globals=[])
+        self.scope_stack.append(scope)
+        self.generic_visit(node)
+        del self.scope_stack[-1]
+        return scope
+
+    def visit_Module(self, node):
+        self._visit_block(node.body, block_required=True,
+                          nodes_required=False, docstring=True)
+        self._visit_with_scope(node)
+
+    def visit_FunctionDef(self, node):
+        self._visit_stored_name(node, node.name)
+        self._visit_block(node.body, block_required=True, docstring=True)
+
+        scope = self._visit_with_scope(node)
+        global_names = set()
+
+        for declaration in scope.globals:
+            for name in declaration.names:
+                if name not in scope.names or name in global_names:
+                    statement = get_statement(declaration)
+                    self.errors.append((declaration,
+                                        'A201 redundant {} declaration for '
+                                        '{}'.format(statement, name)))
+                else:
+                    global_names.add(name)
+
+    visit_ClassDef = visit_FunctionDef
+
+    def visit_Global(self, node):
+        scope = self.scope_stack[-1]
+        scope.globals.append(node)
+
+        if isinstance(scope.node, ast.Module):
+            statement = get_statement(node)
+            self.errors.append((node, 'A201 {} declaration on '
+                                      'top-level'.format(statement)))
+
+    visit_Nonlocal = visit_Global
+
+    def _visit_iter(self, node):
+        if isinstance(node, (ast.Tuple, ast.Set)):
+            self.errors.append((node, 'A101 use lists for data '
+                                      'that have order'))
+
+    def visit_comprehension(self, node):
+        self._visit_iter(node.iter)
+        self.generic_visit(node)
+
+    def visit_For(self, node):
+        self._visit_iter(node.iter)
+        self._visit_block(node.body, block_required=True)
+        self._visit_block(node.orelse)
+        self.generic_visit(node)
+
+    def visit_While(self, node):
+        self._visit_block(node.body, block_required=True)
+        self._visit_block(node.orelse)
+        self.generic_visit(node)
+
+    def visit_BinOp(self, node):
+        if isinstance(node.op, ast.Mod) and isinstance(node.left, ast.Str):
+            self.errors.append((node, 'A107 use format() instead of '
+                                      '% operator for string formatting'))
+
+        multi_addition = (isinstance(node.op, ast.Add) and
+                          isinstance(node.left, ast.BinOp) and
+                          isinstance(node.left.op, ast.Add))
+        if multi_addition and (isinstance(node.left.left, ast.Str) or
+                               isinstance(node.left.right, ast.Str) or
+                               isinstance(node.right, ast.Str)):
+            self.errors.append((node, 'A108 use format() instead of '
+                                      '+ operator when concatenating '
+                                      'more than two strings'))
+
+        self.generic_visit(node)
+
+    def visit_Compare(self, node):
+        left = node.left
+        single = len(node.ops) == 1
+
+        for op, right in zip(node.ops, node.comparators):
+            membership = isinstance(op, (ast.In, ast.NotIn))
+            symmetric = isinstance(op, (ast.Eq, ast.NotEq, ast.Is, ast.IsNot))
+
+            if membership and isinstance(right, (ast.Tuple, ast.List)):
+                self.errors.append((right, 'A102 use sets for distinct '
+                                           'unordered data'))
+
+            consts_first = single and not membership or symmetric
+            if consts_first and is_const(left) and not is_const(right):
+                self.errors.append((left, 'A103 yoda condition'))
+
+            left = right
+
+        self.generic_visit(node)
+
+    def _check_deprecated(self, node, name):
+        substitute = DISCOURAGED_APIS.get(name)
+        if substitute:
+            self.errors.append((node, 'A301 use {}() instead of '
+                                      '{}()'.format(substitute, name)))
+
+    def visit_Call(self, node):
+        func = get_identifier(node.func)
+        arg = next(iter(node.args), None)
+        redundant_literal = False
+
+        if isinstance(arg, ast.Lambda) and func in {'map', 'filter',
+                                                    'imap', 'ifilter',
+                                                    'itertools.imap',
+                                                    'itertools.ifilter'}:
+            self.errors.append((node, 'A104 use a comprehension '
+                                      'instead of calling {}() with '
+                                      'lambda function'.format(func)))
+        elif isinstance(arg, (ast.List, ast.Tuple)):
+            if func == 'dict':
+                redundant_literal = all(isinstance(elt, (ast.Tuple, ast.List))
+                                        for elt in arg.elts)
+            else:
+                redundant_literal = func in {'list', 'set', 'tuple'}
+        elif isinstance(arg, (ast.ListComp, ast.GeneratorExp)):
+            if func == 'dict':
+                redundant_literal = isinstance(arg.elt, (ast.Tuple, ast.List))
+            else:
+                redundant_literal = func in {'list', 'set'}
+
+        if redundant_literal:
+            self.errors.append((node, 'A105 use a {0} literal or '
+                                      'comprehension instead of calling '
+                                      '{0}()'.format(func)))
+
+        self._check_deprecated(node, func)
+        self.generic_visit(node)
+
+    def visit_Import(self, node):
+        for alias in node.names:
+            self._visit_stored_name(node, alias.asname or alias.name)
+
+            if hasattr(node, 'module'):
+                self._check_deprecated(node, '{}.{}'.format(node.module,
+                                                            alias.name))
+
+    visit_ImportFrom = visit_Import
+
+    def visit_Assign(self, node):
+        if isinstance(node.value, ast.BinOp) and len(node.targets) == 1:
+            target = node.targets[0]
+            left_is_target = (isinstance(target, ast.Name) and
+                              isinstance(node.value.left, ast.Name) and
+                              target.id == node.value.left.id)
+            if left_is_target:
+                self.errors.append((node, 'A106 use augment assignment, '
+                                          'e.g. x += y instead x = x + y'))
+        self.generic_visit(node)
+
+    def _visit_hash_keys(self, nodes, what):
+        keys = []
+        for node in nodes:
+            key = evaluate(node)
+            if key is VOLATILE:
+                continue
+
+            if key in keys:
+                self.errors.append((node, 'A207 duplicate ' + what))
+                continue
+
+            keys.append(key)
+
+    def visit_Dict(self, node):
+        self._visit_hash_keys(node.keys, 'key in dict')
+
+    def visit_Set(self, node):
+        self._visit_hash_keys(node.elts, 'item in set')
+
+
+class ASTChecker(object):
+    name = 'abp'
+    version = __version__
+
+    def __init__(self, tree, filename):
+        self.tree = tree
+
+    def run(self):
+        visitor = TreeVisitor()
+        visitor.visit(self.tree)
+
+        for node, error in visitor.errors:
+            yield (node.lineno, node.col_offset, error, type(self))
+
+
+def check_non_default_encoding(physical_line, line_number):
+    if line_number <= 2 and re.search(r'^\s*#.*coding[:=]', physical_line):
+        return (0, 'A303 non-default file encoding')
+
+check_non_default_encoding.name = 'abp-non-default-encoding'
+check_non_default_encoding.version = __version__
+
+
+def check_quotes(logical_line, tokens, previous_logical):
+    first_token = True
+
+    for kind, token, start, end, _ in tokens:
+        if kind == tokenize.INDENT or kind == tokenize.DEDENT:
+            continue
+
+        if kind == tokenize.STRING:
+            match = re.search(r'^(u)?(b)?(r)?((""")?.*)$',
+                              token, re.IGNORECASE | re.DOTALL)
+            (is_unicode, is_bytes, is_raw,
+             literal, has_doc_quotes) = match.groups()
+
+            if first_token and re.search(r'^(?:(?:def|class)\s|$)',
+                                         previous_logical):
+                if not has_doc_quotes:
+                    yield (start, 'A109 use triple double '
+                                  'quotes for docstrings')
+                elif is_unicode or is_bytes or is_raw:
+                    yield (start, "A109 don't use u'', b'' "
+                                  "or r'' for doc strings")
+            elif start[0] == end[0]:
+                if is_raw:
+                    literal = re.sub(r'\\(?!{})'.format(literal[0]),
+                                     '\\\\\\\\', literal)
+
+                if sys.version_info[0] >= 3:
+                    if is_bytes:
+                        literal = 'b' + literal
+                elif is_unicode:
+                    literal = 'u' + literal
+
+                if ascii(eval(literal)) != literal:
+                    yield (start, "A110 string literal doesn't match"
+                                  '{}()'.format(ascii.__name__))
+
+        first_token = False
+
+check_quotes.name = 'abp-quotes'
+check_quotes.version = __version__
+
+
+def check_redundant_parenthesis(logical_line, tokens):
+    start_line = tokens[0][2][0]
+    level = 0
+    statement = None
+
+    for i, (kind, token, _, end, _) in enumerate(tokens):
+        if kind == tokenize.INDENT or kind == tokenize.DEDENT:
+            continue
+
+        if statement is None:
+            # logical line doesn't start with an if, elif or while statement
+            if kind != tokenize.NAME or token not in {'if', 'elif', 'while'}:
+                break
+
+            # expression doesn't start with parenthesis
+            next_token = tokens[i + 1]
+            if next_token[:2] != (tokenize.OP, '('):
+                break
+
+            # expression is empty tuple
+            if tokens[i + 2][:2] == (tokenize.OP, ')'):
+                break
+
+            statement = token
+            pos = next_token[2]
+            continue
+
+        # expression ends on a different line, parenthesis are necessary
+        if end[0] > start_line:
+            break
+
+        if kind == tokenize.OP:
+            if token == ',':
+                # expression is non-empty tuple
+                if level == 1:
+                    break
+            elif token == '(':
+                level += 1
+            elif token == ')':
+                level -= 1
+                if level == 0:
+                    # outer parenthesis closed before end of expression
+                    if tokens[i + 1][:2] != (tokenize.OP, ':'):
+                        break
+
+                    return [(pos, 'A111 redundant parenthesis for {} '
+                                  'statement'.format(statement))]
+
+    return []
+
+check_redundant_parenthesis.name = 'abp-redundant-parenthesis'
+check_redundant_parenthesis.version = __version__