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 +1,238 @@
+# 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'

[Sebastian Noack, 2016/04/21 19:02:12]

It would be kinda cool if we could inject the version based on the mercurial
revision as a build step, given that we probably won't have releases for this
peace of code, and that it can only be used with flake8 after installing it via
setup.py, anyway.

However, I already spend more time than intended on this. But if you know from
the top of your head how to do that, or if you'd volunteer to look into that
later, that would be cool. ;)

+
+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)
+
+
+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, ast.Dict)):
+            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_Call(self, node):
+        func = node.func
+        if isinstance(func, ast.Name) and func.id in {'filter', 'map'}:
+            if len(node.args) > 0 and isinstance(node.args[0], ast.Lambda):
+                self.errors.append((node, 'A131 use a comprehension '
+                                          'instead calling {}() with '
+                                          'lambda function'.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(m, 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)
+
+
+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):
+    first_token = True
+    offset = 0
+
+    for kind, token, start, end, _ in tokens:
+        if kind == tokenize.INDENT:
+            offset = end[1]
+            continue
+
+        if kind == tokenize.STRING:
+            pos = start[1] - offset
+            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 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__