checks.py 文件源码

def _check_string_formatting(self, node):
        [lhs, rhs] = [node.left, node.right]
        if isinstance(lhs, ast.Str):
            lhs = lhs.s
        else:
            return
        if isinstance(rhs, ast.Tuple):
            if sys.version_info >= (3, 5):
                if any(isinstance(elt, ast.Starred) for elt in rhs.elts):  # pylint: disable=no-member
                    return
            rhs = tuple(
                elt.s if isinstance(elt, ast.Str) else 0
                for elt in rhs.elts
            )
        elif isinstance(rhs, ast.Dict):
            new_rhs = {}
            for key, value in zip(rhs.keys, rhs.values):
                if isinstance(key, ast.Str):
                    key = key.s
                else:
                    return
                if isinstance(value, ast.Str):
                    value = value.s
                else:
                    value = 0
                new_rhs[key] = value
            rhs = new_rhs
        elif isinstance(rhs, ast.Str):
            rhs = rhs.s
        elif isinstance(rhs, ast.Num):
            rhs = 0
        else:
            return
        try:
            lhs % rhs
        except KeyError as exc:
            yield self.tag(node, 'string-formatting-error', 'missing key', str(exc))
        except Exception as exc:  # pylint: disable=broad-except
            yield self.tag(node, 'string-formatting-error', str(exc))