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

flake8-abp/flake8_abp.py

Index: flake8-abp/flake8_abp.py
===================================================================
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+++ b/flake8-abp/flake8_abp.py
@@ -0,0 +1,352 @@
+# 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
+
+__version__ = '0.1'
+
+DEPRECATED_APIS = {
+    ('re', 'match'): 'A101 use re.search() instead re.match()',
+    ('codecs', 'open'): 'A102 use io.open() instead codecs.open()',
+}
+
+BAILOUT = (ast.Return, ast.Raise, ast.Continue, ast.Break)
+
+
+def is_const(node):
+    if isinstance(node, (ast.Str, ast.Num)):
+        return True
+    if hasattr(ast, 'Bytes') and isinstance(node, ast.Bytes):
+        return True
+
+    if isinstance(node, (ast.Tuple, ast.List, ast.Set)):
+        return all(is_const(elt) for elt in node.elts)
+    if isinstance(node, ast.Name):
+        return node.id in {'None', 'True', 'False'}
+    if isinstance(node, ast.BinOp):
+        return is_const(node.left) and is_const(node.right)
+    if isinstance(node, ast.UnaryOp):
+        return is_const(node.operand)
+
+    return False
+
+
+class TreeVisitor(ast.NodeVisitor):
+    def __init__(self):
+        self.errors = []
+        self.stack = []
+
+    def _visit_block(self, nodes, mandatory=False, docstring=False):
+        pass_node = None
+        bailed = False
+        dead_code = False
+
+        for node in nodes:
+            if isinstance(node, ast.Pass):
+                pass_node = node
+
+            if bailed and not dead_code:
+                dead_code = True
+                self.errors.append((node, 'A151 dead code after '
+                                          'return/raise/continue/break'))
+
+            if isinstance(node, BAILOUT):
+                bailed = True
+
+            if not isinstance(node, ast.Expr):
+                continue
+            if isinstance(node.value, (ast.Call, ast.Yield)):
+                continue
+            if docstring and node is nodes[0] and isinstance(node.value, ast.Str):
+                continue
+
+            self.errors.append((node, 'A152 unused expression'))
+
+        if pass_node:
+            if len(nodes) > 1:
+                self.errors.append((pass_node, 'A153 redundant pass statement'))
+
+            if not mandatory and all(isinstance(n, ast.Pass) for n in nodes):
+                self.errors.append((pass_node, 'A154 empty block'))
+
+    def _visit_block_node(self, node, **kwargs):
+        self._visit_block(node.body, **kwargs)
+        if hasattr(node, 'orelse'):
+            self._visit_block(node.orelse)
+        if hasattr(node, 'finalbody'):
+            self._visit_block(node.finalbody)
+        self.generic_visit(node)
+
+    visit_Try = visit_TryExcept = visit_TryFinally = _visit_block_node
+
+    visit_ExceptHandler = visit_While = \
+        lambda self, node: self._visit_block_node(node, mandatory=True)
+
+    visit_Module = visit_ClassDef = \
+        lambda self, node: self._visit_block_node(node, mandatory=True,
+                                                        docstring=True)
+
+    def visit_Attribute(self, node):
+        if isinstance(node.ctx, ast.Load) and isinstance(node.value, ast.Name):
+            error = DEPRECATED_APIS.get((node.value.id, node.attr))
+            if error:
+                self.errors.append((node, error))
+        self.generic_visit(node)
+
+    def visit_ImportFrom(self, node):
+        for alias in node.names:
+            error = DEPRECATED_APIS.get((node.module, alias.name))
+            if error:
+                self.errors.append((node, error))
+
+    def visit_BinOp(self, node):
+        if isinstance(node.op, ast.Mod) and isinstance(node.left, ast.Str):
+            self.errors.append((node, 'A111 use format() instead % 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, 'A112 use format() instead + operator '
+                                      'when concatenating >2 strings'))
+
+        self.generic_visit(node)
+
+    def visit_comprehension(self, node):
+        if isinstance(node.iter, (ast.Tuple, ast.Set)):
+            self.errors.append((node.iter, 'A121 use lists for data '
+                                           'that have order'))
+        self.generic_visit(node)
+
+    def visit_For(self, node):
+        self._visit_block(node.body, mandatory=True)
+        self.visit_comprehension(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, 'A122 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, 'A123 yoda condition'))
+
+            left = right
+
+        self.generic_visit(node)
+
+    def visit_Call(self, node):
+        func = node.func
+        if isinstance(func, ast.Name) and len(node.args) > 0:
+            arg = node.args[0]
+
+            if isinstance(arg, ast.Lambda) and func.id in {'filter', 'map'}:
+                self.errors.append((node, 'A131 use a comprehension '
+                                          'instead calling {}() with '
+                                          'lambda function'.format(func.id)))
+
+            if isinstance(arg, (ast.ListComp, ast.GeneratorExp)):
+                redundant_comp = func.id in {'list', 'set'}
+                if func.id == 'dict':
+                    redundant_comp = isinstance(arg.elt, (ast.Tuple, ast.List))
+
+                if redundant_comp:
+                    self.errors.append((node, 'A132 use a {0} comprehension '
+                                              'instead calling the {0}() '
+                                              'constructor'.format(func.id)))
+
+        self.generic_visit(node)
+
+    def visit_FunctionDef(self, node):
+        self._visit_block(node.body, mandatory=True, docstring=True)
+
+        self.stack.append((set(), []))
+        self.generic_visit(node)
+        targets, globals = self.stack.pop()
+
+        for var in globals:
+            if any(name not in targets for name in var.names):
+                self.errors.append((var, 'A141 redundant global/nonlocal '
+                                         'declaration'))
+
+    def visit_Name(self, node):
+        if self.stack and isinstance(node.ctx, ast.Store):
+            self.stack[-1][0].add(node.id)
+
+    def visit_Global(self, node):
+        if self.stack:
+            self.stack[-1][1].append(node)
+        else:
+            self.errors.append((node, 'A141 global/nonlocal declaration '
+                                      'on top-level'))
+
+    visit_Nonlocal = visit_Global
+
+    def visit_If(self, node):
+        has_else = bool(node.orelse)
+
+        if has_else and any(isinstance(n, BAILOUT) for n in node.body):
+            self.errors.append((node, 'A159 redundant else statement after '
+                                      'return/raise/continue/break '
+                                      'in if-clause'))
+
+        self._visit_block(node.body, mandatory=has_else)
+        self._visit_block(node.orelse)
+        self.generic_visit(node)
+
+    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, 'A161 use in-place assignment, '
+                                          'e.g. x += y instead x = x + y'))
+        self.generic_visit(node)
+
+
+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, 'A201 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, indent_level):
+    first_token = True
+
+    for kind, token, start, end, _ in tokens:
+        if kind == tokenize.INDENT:
+            continue
+
+        if kind == tokenize.STRING:
+            pos = start[1] - indent_level
+            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 (pos, 'A301 use triple double quotes for docstrings')
+                if is_unicode or is_bytes or is_raw:
+                    yield (pos, "A302 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
+                    else:
+                        literal = re.sub(r'(?<!\\)\\x(?!a[0d])([a-f][0-9a-f])',
+                                         lambda m: chr(int(m.group(1), 16)),
+                                         literal)
+                elif is_unicode:
+                    literal = 'u' + literal
+
+                if repr(eval(literal)) != literal:
+                    yield (pos, "A311 string literal doesn't match repr()")
+
+        first_token = False
+
+check_quotes.name = 'abp-quotes'
+check_quotes.version = __version__
+
+
+def check_redundant_parenthesis(logical_line, tokens, indent_level):
+    start_line = tokens[0][2][0]
+    level = 0
+    statement = None
+
+    for i, (kind, token, _, end, _) in enumerate(tokens):
+        if kind == tokenize.INDENT:
+            continue
+
+        if statement is None:
+            # logical line doesn't start with an if or while statement
+            if kind != tokenize.NAME or token not in {'if', '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][1] - indent_level
+            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, 'A401 redundant parenthesis for {} '
+                                  'statement'.format(statement))]
+
+    return []
+
+check_redundant_parenthesis.name = 'abp-redundant-parenthesis'
+check_redundant_parenthesis.version = __version__