Add pylint to depot_tools.

third_party/pylint/checkers/utils.py

+# pylint: disable=W0611
+#
+# Copyright (c) 2003-2010 LOGILAB S.A. (Paris, FRANCE).
+# http://www.logilab.fr/ -- mailto:contact@logilab.fr
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program 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
+# this program; if not, write to the Free Software Foundation, Inc.,
+# 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+"""some functions that may be useful for various checkers
+"""
+
+import string
+from logilab import astng
+from logilab.common.compat import builtins
+BUILTINS_NAME = builtins.__name__
+
+COMP_NODE_TYPES = astng.ListComp, astng.SetComp, astng.DictComp, astng.GenExpr
+
+def is_inside_except(node):
+    """Returns true if node is directly inside an exception handler"""
+    return isinstance(node.parent, astng.ExceptHandler)
+
+
+def clobber_in_except(node):
+    """Checks if an assignment node in an except handler clobbers an existing
+    variable.
+
+    Returns (True, args for W0623) if assignment clobbers an existing variable,
+    (False, None) otherwise.
+    """
+    if isinstance(node, astng.AssAttr):
+        return (True, (node.attrname, 'object %r' % (node.expr.name,)))
+    elif node is not None:
+        name = node.name
+        if is_builtin(name):
+            return (True, (name, 'builtins'))
+        else:
+            scope, stmts = node.lookup(name)
+            if (stmts and 
+                not isinstance(stmts[0].ass_type(), 
+                               (astng.Assign, astng.AugAssign, astng.ExceptHandler))):
+                return (True, (name, 'outer scope (line %i)' % (stmts[0].lineno,)))
+    return (False, None)
+
+
+def safe_infer(node):
+    """return the inferred value for the given node.
+    Return None if inference failed or if there is some ambiguity (more than
+    one node has been inferred)
+    """
+    try:
+        inferit = node.infer()
+        value = inferit.next()
+    except astng.InferenceError:
+        return
+    try:
+        inferit.next()
+        return # None if there is ambiguity on the inferred node
+    except StopIteration:
+        return value
+
+def is_super(node):
+    """return True if the node is referencing the "super" builtin function
+    """
+    if getattr(node, 'name', None) == 'super' and \
+           node.root().name == BUILTINS_NAME:
+        return True
+    return False
+
+def is_error(node):
+    """return true if the function does nothing but raising an exception"""
+    for child_node in node.get_children():
+        if isinstance(child_node, astng.Raise):
+            return True
+        return False
+
+def is_raising(body):
+    """return true if the given statement node raise an exception"""
+    for node in body:
+        if isinstance(node, astng.Raise):
+            return True
+    return False
+
+def is_empty(body):
+    """return true if the given node does nothing but 'pass'"""
+    return len(body) == 1 and isinstance(body[0], astng.Pass)
+
+builtins =  __builtins__.copy()
+SPECIAL_BUILTINS = ('__builtins__',) # '__path__', '__file__')
+
+def is_builtin(name): # was is_native_builtin
+    """return true if <name> could be considered as a builtin defined by python
+    """
+    if name in builtins:
+        return True
+    if name in SPECIAL_BUILTINS:
+        return True
+    return False
+
+def is_defined_before(var_node):
+    """return True if the variable node is defined by a parent node (list,
+    set, dict, or generator comprehension, lambda) or in a previous sibling
+    node on the same line (statement_defining ; statement_using)
+    """
+    varname = var_node.name
+    _node = var_node.parent
+    while _node:
+        if isinstance(_node, COMP_NODE_TYPES):
+            for ass_node in _node.nodes_of_class(astng.AssName):
+                if ass_node.name == varname:
+                    return True
+        elif isinstance(_node, astng.For):
+            for ass_node in _node.target.nodes_of_class(astng.AssName):
+                if ass_node.name == varname:
+                    return True
+        elif isinstance(_node, astng.With):
+            if _node.vars is None:
+                # quickfix : case in which 'with' is used without 'as'
+                return False
+            if _node.vars.name == varname:
+                return True
+        elif isinstance(_node, (astng.Lambda, astng.Function)):
+            if _node.args.is_argument(varname):
+                return True
+            if getattr(_node, 'name', None) == varname:
+                return True
+            break
+        _node = _node.parent
+    # possibly multiple statements on the same line using semi colon separator
+    stmt = var_node.statement()
+    _node = stmt.previous_sibling()
+    lineno = stmt.fromlineno
+    while _node and _node.fromlineno == lineno:
+        for ass_node in _node.nodes_of_class(astng.AssName):
+            if ass_node.name == varname:
+                return True
+        for imp_node in _node.nodes_of_class( (astng.From, astng.Import)):
+            if varname in [name[1] or name[0] for name in imp_node.names]:
+                return True
+        _node = _node.previous_sibling()
+    return False
+
+def is_func_default(node):
+    """return true if the given Name node is used in function default argument's
+    value
+    """
+    parent = node.scope()
+    if isinstance(parent, astng.Function):
+        for default_node in parent.args.defaults:
+            for default_name_node in default_node.nodes_of_class(astng.Name):
+                if default_name_node is node:
+                    return True
+    return False
+
+def is_func_decorator(node):
+    """return true if the name is used in function decorator"""
+    parent = node.parent
+    while parent is not None:
+        if isinstance(parent, astng.Decorators):
+            return True
+        if parent.is_statement or isinstance(parent, astng.Lambda):
+            break
+        parent = parent.parent
+    return False
+
+def is_ancestor_name(frame, node):
+    """return True if `frame` is a astng.Class node with `node` in the
+    subtree of its bases attribute
+    """
+    try:
+        bases = frame.bases
+    except AttributeError:
+        return False
+    for base in bases:
+        if node in base.nodes_of_class(astng.Name):
+            return True
+    return False
+
+def assign_parent(node):
+    """return the higher parent which is not an AssName, Tuple or List node
+    """
+    while node and isinstance(node, (astng.AssName,
+                                     astng.Tuple,
+                                     astng.List)):
+        node = node.parent
+    return node
+
+def overrides_an_abstract_method(class_node, name):
+    """return True if pnode is a parent of node"""
+    for ancestor in class_node.ancestors():
+        if name in ancestor and isinstance(ancestor[name], astng.Function) and \
+               ancestor[name].is_abstract(pass_is_abstract=False):
+            return True
+    return False
+
+def overrides_a_method(class_node, name):
+    """return True if <name> is a method overridden from an ancestor"""
+    for ancestor in class_node.ancestors():
+        if name in ancestor and isinstance(ancestor[name], astng.Function):
+            return True
+    return False
+
+PYMETHODS = set(('__new__', '__init__', '__del__', '__hash__',
+                 '__str__', '__repr__',
+                 '__len__', '__iter__',
+                 '__delete__', '__get__', '__set__',
+                 '__getitem__', '__setitem__', '__delitem__', '__contains__',
+                 '__getattribute__', '__getattr__', '__setattr__', '__delattr__',
+                 '__call__',
+                 '__enter__', '__exit__',
+                 '__cmp__', '__ge__', '__gt__', '__le__', '__lt__', '__eq__',
+                 '__nonzero__', '__neg__', '__invert__',
+                 '__mul__', '__imul__', '__rmul__',
+                 '__div__', '__idiv__', '__rdiv__',
+                 '__add__', '__iadd__', '__radd__',
+                 '__sub__', '__isub__', '__rsub__',
+                 '__pow__', '__ipow__', '__rpow__',
+                 '__mod__', '__imod__', '__rmod__',
+                 '__and__', '__iand__', '__rand__',
+                 '__or__', '__ior__', '__ror__',
+                 '__xor__', '__ixor__', '__rxor__',
+                 # XXX To be continued
+                 ))
+
+def check_messages(*messages):
+    """decorator to store messages that are handled by a checker method"""
+
+    def store_messages(func):
+        func.checks_msgs = messages
+        return func
+    return store_messages
+
+class IncompleteFormatString(Exception):
+    """A format string ended in the middle of a format specifier."""
+    pass
+
+class UnsupportedFormatCharacter(Exception):
+    """A format character in a format string is not one of the supported
+    format characters."""
+    def __init__(self, index):
+        Exception.__init__(self, index)
+        self.index = index
+
+def parse_format_string(format_string):
+    """Parses a format string, returning a tuple of (keys, num_args), where keys
+    is the set of mapping keys in the format string, and num_args is the number
+    of arguments required by the format string.  Raises
+    IncompleteFormatString or UnsupportedFormatCharacter if a
+    parse error occurs."""
+    keys = set()
+    num_args = 0
+    def next_char(i):
+        i += 1
+        if i == len(format_string):
+            raise IncompleteFormatString
+        return (i, format_string[i])
+    i = 0
+    while i < len(format_string):
+        c = format_string[i]
+        if c == '%':
+            i, c = next_char(i)
+            # Parse the mapping key (optional).
+            key = None
+            if c == '(':
+                depth = 1
+                i, c = next_char(i)
+                key_start = i
+                while depth != 0:
+                    if c == '(':
+                        depth += 1
+                    elif c == ')':
+                        depth -= 1
+                    i, c = next_char(i)
+                key_end = i - 1
+                key = format_string[key_start:key_end]
+
+            # Parse the conversion flags (optional).
+            while c in '#0- +':
+                i, c = next_char(i)
+            # Parse the minimum field width (optional).
+            if c == '*':
+                num_args += 1
+                i, c = next_char(i)
+            else:
+                while c in string.digits:
+                    i, c = next_char(i)
+            # Parse the precision (optional).
+            if c == '.':
+                i, c = next_char(i)
+                if c == '*':
+                    num_args += 1
+                    i, c = next_char(i)
+                else:
+                    while c in string.digits:
+                        i, c = next_char(i)
+            # Parse the length modifier (optional).
+            if c in 'hlL':
+                i, c = next_char(i)
+            # Parse the conversion type (mandatory).
+            if c not in 'diouxXeEfFgGcrs%':
+                raise UnsupportedFormatCharacter(i)
+            if key:
+                keys.add(key)
+            elif c != '%':
+                num_args += 1
+        i += 1
+    return keys, num_args