Esempio n. 1
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    def py__getattribute__(self,
                           name_or_str,
                           name_context=None,
                           position=None,
                           analysis_errors=True):
        """
        :param position: Position of the last statement -> tuple of line, column
        """
        if name_context is None:
            name_context = self
        names = self.goto(name_or_str, position)

        string_name = name_or_str.value if isinstance(name_or_str,
                                                      Name) else name_or_str

        # This paragraph is currently needed for proper branch type inference
        # (static analysis).
        found_predefined_types = None
        if self.predefined_names and isinstance(name_or_str, Name):
            node = name_or_str
            while node is not None and not parser_utils.is_scope(node):
                node = node.parent
                if node.type in ("if_stmt", "for_stmt", "comp_for",
                                 'sync_comp_for'):
                    try:
                        name_dict = self.predefined_names[node]
                        types = name_dict[string_name]
                    except KeyError:
                        continue
                    else:
                        found_predefined_types = types
                        break
        if found_predefined_types is not None and names:
            from medi.inference import flow_analysis
            check = flow_analysis.reachability_check(
                context=self,
                value_scope=self.tree_node,
                node=name_or_str,
            )
            if check is flow_analysis.UNREACHABLE:
                values = NO_VALUES
            else:
                values = found_predefined_types
        else:
            values = ValueSet.from_sets(name.infer() for name in names)

        if not names and not values and analysis_errors:
            if isinstance(name_or_str, Name):
                from medi.inference import analysis
                message = ("NameError: name '%s' is not defined." %
                           string_name)
                analysis.add(name_context, 'name-error', name_or_str, message)

        debug.dbg('context.names_to_types: %s -> %s', names, values)
        if values:
            return values
        return self._check_for_additional_knowledge(name_or_str, name_context,
                                                    position)
Esempio n. 2
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        def parent_scope(node):
            while True:
                node = node.parent

                if parser_utils.is_scope(node):
                    return node
                elif node.type in ('argument', 'testlist_comp'):
                    if node.children[1].type in ('comp_for', 'sync_comp_for'):
                        return node.children[1]
                elif node.type == 'dictorsetmaker':
                    for n in node.children[1:4]:
                        # In dictionaries it can be pretty much anything.
                        if n.type in ('comp_for', 'sync_comp_for'):
                            return n
Esempio n. 3
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def check_flow_information(value, flow, search_name, pos):
    """ Try to find out the type of a variable just with the information that
    is given by the flows: e.g. It is also responsible for assert checks.::

        if isinstance(k, str):
            k.  # <- completion here

    ensures that `k` is a string.
    """
    if not settings.dynamic_flow_information:
        return None

    result = None
    if is_scope(flow):
        # Check for asserts.
        module_node = flow.get_root_node()
        try:
            names = module_node.get_used_names()[search_name.value]
        except KeyError:
            return None
        names = reversed([
            n for n in names
            if flow.start_pos <= n.start_pos < (pos or flow.end_pos)
        ])

        for name in names:
            ass = search_ancestor(name, 'assert_stmt')
            if ass is not None:
                result = _check_isinstance_type(value, ass.assertion,
                                                search_name)
                if result is not None:
                    return result

    if flow.type in ('if_stmt', 'while_stmt'):
        potential_ifs = [c for c in flow.children[1::4] if c != ':']
        for if_test in reversed(potential_ifs):
            if search_name.start_pos > if_test.end_pos:
                return _check_isinstance_type(value, if_test, search_name)
    return result
Esempio n. 4
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def infer_node(context, element):
    if isinstance(context, CompForContext):
        return _infer_node(context, element)

    if_stmt = element
    while if_stmt is not None:
        if_stmt = if_stmt.parent
        if if_stmt.type in ('if_stmt', 'for_stmt'):
            break
        if parser_utils.is_scope(if_stmt):
            if_stmt = None
            break
    predefined_if_name_dict = context.predefined_names.get(if_stmt)
    # TODO there's a lot of issues with this one. We actually should do
    # this in a different way. Caching should only be active in certain
    # cases and this all sucks.
    if predefined_if_name_dict is None and if_stmt \
            and if_stmt.type == 'if_stmt' and context.inference_state.is_analysis:
        if_stmt_test = if_stmt.children[1]
        name_dicts = [{}]
        # If we already did a check, we don't want to do it again -> If
        # value.predefined_names is filled, we stop.
        # We don't want to check the if stmt itself, it's just about
        # the content.
        if element.start_pos > if_stmt_test.end_pos:
            # Now we need to check if the names in the if_stmt match the
            # names in the suite.
            if_names = get_names_of_node(if_stmt_test)
            element_names = get_names_of_node(element)
            str_element_names = [e.value for e in element_names]
            if any(i.value in str_element_names for i in if_names):
                for if_name in if_names:
                    definitions = context.inference_state.infer(context, if_name)
                    # Every name that has multiple different definitions
                    # causes the complexity to rise. The complexity should
                    # never fall below 1.
                    if len(definitions) > 1:
                        if len(name_dicts) * len(definitions) > 16:
                            debug.dbg('Too many options for if branch inference %s.', if_stmt)
                            # There's only a certain amount of branches
                            # Medi can infer, otherwise it will take to
                            # long.
                            name_dicts = [{}]
                            break

                        original_name_dicts = list(name_dicts)
                        name_dicts = []
                        for definition in definitions:
                            new_name_dicts = list(original_name_dicts)
                            for i, name_dict in enumerate(new_name_dicts):
                                new_name_dicts[i] = name_dict.copy()
                                new_name_dicts[i][if_name.value] = ValueSet([definition])

                            name_dicts += new_name_dicts
                    else:
                        for name_dict in name_dicts:
                            name_dict[if_name.value] = definitions
        if len(name_dicts) > 1:
            result = NO_VALUES
            for name_dict in name_dicts:
                with context.predefine_names(if_stmt, name_dict):
                    result |= _infer_node(context, element)
            return result
        else:
            return _infer_node_if_inferred(context, element)
    else:
        if predefined_if_name_dict:
            return _infer_node(context, element)
        else:
            return _infer_node_if_inferred(context, element)
Esempio n. 5
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def _get_flow_scopes(node):
    while True:
        node = get_parent_scope(node, include_flows=True)
        if node is None or is_scope(node):
            return
        yield node