# Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html # For details: https://github.com/PyCQA/astroid/blob/main/LICENSE # Copyright (c) https://github.com/PyCQA/astroid/blob/main/CONTRIBUTORS.txt """_filter_stmts and helper functions. This method gets used in LocalsDictnodes.NodeNG._scope_lookup. It is not considered public. """ from __future__ import annotations from astroid import nodes def _get_filtered_node_statements( base_node: nodes.NodeNG, stmt_nodes: list[nodes.NodeNG] ) -> list[tuple[nodes.NodeNG, nodes.Statement]]: statements = [(node, node.statement(future=True)) for node in stmt_nodes] # Next we check if we have ExceptHandlers that are parent # of the underlying variable, in which case the last one survives if len(statements) > 1 and all( isinstance(stmt, nodes.ExceptHandler) for _, stmt in statements ): statements = [ (node, stmt) for node, stmt in statements if stmt.parent_of(base_node) ] return statements def _is_from_decorator(node) -> bool: """Return whether the given node is the child of a decorator.""" return any(isinstance(parent, nodes.Decorators) for parent in node.node_ancestors()) def _get_if_statement_ancestor(node: nodes.NodeNG) -> nodes.If | None: """Return the first parent node that is an If node (or None).""" for parent in node.node_ancestors(): if isinstance(parent, nodes.If): return parent return None def _filter_stmts(base_node: nodes.NodeNG, stmts, frame, offset): """Filter the given list of statements to remove ignorable statements. If base_node is not a frame itself and the name is found in the inner frame locals, statements will be filtered to remove ignorable statements according to base_node's location. :param stmts: The statements to filter. :type stmts: list(nodes.NodeNG) :param frame: The frame that all of the given statements belong to. :type frame: nodes.NodeNG :param offset: The line offset to filter statements up to. :type offset: int :returns: The filtered statements. :rtype: list(nodes.NodeNG) """ # if offset == -1, my actual frame is not the inner frame but its parent # # class A(B): pass # # we need this to resolve B correctly if offset == -1: myframe = base_node.frame().parent.frame() else: myframe = base_node.frame() # If the frame of this node is the same as the statement # of this node, then the node is part of a class or # a function definition and the frame of this node should be the # the upper frame, not the frame of the definition. # For more information why this is important, # see Pylint issue #295. # For example, for 'b', the statement is the same # as the frame / scope: # # def test(b=1): # ... if ( base_node.parent and base_node.statement(future=True) is myframe and myframe.parent ): myframe = myframe.parent.frame() mystmt: nodes.Statement | None = None if base_node.parent: mystmt = base_node.statement(future=True) # line filtering if we are in the same frame # # take care node may be missing lineno information (this is the case for # nodes inserted for living objects) if myframe is frame and mystmt and mystmt.fromlineno is not None: assert mystmt.fromlineno is not None, mystmt mylineno = mystmt.fromlineno + offset else: # disabling lineno filtering mylineno = 0 _stmts = [] _stmt_parents = [] statements = _get_filtered_node_statements(base_node, stmts) for node, stmt in statements: # line filtering is on and we have reached our location, break if stmt.fromlineno and stmt.fromlineno > mylineno > 0: break # Ignore decorators with the same name as the # decorated function # Fixes issue #375 if mystmt is stmt and _is_from_decorator(base_node): continue if node.has_base(base_node): break if isinstance(node, nodes.EmptyNode): # EmptyNode does not have assign_type(), so just add it and move on _stmts.append(node) continue assign_type = node.assign_type() _stmts, done = assign_type._get_filtered_stmts(base_node, node, _stmts, mystmt) if done: break optional_assign = assign_type.optional_assign if optional_assign and assign_type.parent_of(base_node): # we are inside a loop, loop var assignment is hiding previous # assignment _stmts = [node] _stmt_parents = [stmt.parent] continue if isinstance(assign_type, nodes.NamedExpr): # If the NamedExpr is in an if statement we do some basic control flow inference if_parent = _get_if_statement_ancestor(assign_type) if if_parent: # If the if statement is within another if statement we append the node # to possible statements if _get_if_statement_ancestor(if_parent): optional_assign = False _stmts.append(node) _stmt_parents.append(stmt.parent) # If the if statement is first-level and not within an orelse block # we know that it will be evaluated elif not if_parent.is_orelse: _stmts = [node] _stmt_parents = [stmt.parent] # Else we do not known enough about the control flow to be 100% certain # and we append to possible statements else: _stmts.append(node) _stmt_parents.append(stmt.parent) else: _stmts = [node] _stmt_parents = [stmt.parent] # XXX comment various branches below!!! try: pindex = _stmt_parents.index(stmt.parent) except ValueError: pass else: # we got a parent index, this means the currently visited node # is at the same block level as a previously visited node if _stmts[pindex].assign_type().parent_of(assign_type): # both statements are not at the same block level continue # if currently visited node is following previously considered # assignment and both are not exclusive, we can drop the # previous one. For instance in the following code :: # # if a: # x = 1 # else: # x = 2 # print x # # we can't remove neither x = 1 nor x = 2 when looking for 'x' # of 'print x'; while in the following :: # # x = 1 # x = 2 # print x # # we can remove x = 1 when we see x = 2 # # moreover, on loop assignment types, assignment won't # necessarily be done if the loop has no iteration, so we don't # want to clear previous assignments if any (hence the test on # optional_assign) if not (optional_assign or nodes.are_exclusive(_stmts[pindex], node)): del _stmt_parents[pindex] del _stmts[pindex] # If base_node and node are exclusive, then we can ignore node if nodes.are_exclusive(base_node, node): continue # An AssignName node overrides previous assignments if: # 1. node's statement always assigns # 2. node and base_node are in the same block (i.e., has the same parent as base_node) if isinstance(node, (nodes.NamedExpr, nodes.AssignName)): if isinstance(stmt, nodes.ExceptHandler): # If node's statement is an ExceptHandler, then it is the variable # bound to the caught exception. If base_node is not contained within # the exception handler block, node should override previous assignments; # otherwise, node should be ignored, as an exception variable # is local to the handler block. if stmt.parent_of(base_node): _stmts = [] _stmt_parents = [] else: continue elif not optional_assign and mystmt and stmt.parent is mystmt.parent: _stmts = [] _stmt_parents = [] elif isinstance(node, nodes.DelName): # Remove all previously stored assignments _stmts = [] _stmt_parents = [] continue # Add the new assignment _stmts.append(node) if isinstance(node, nodes.Arguments) or isinstance( node.parent, nodes.Arguments ): # Special case for _stmt_parents when node is a function parameter; # in this case, stmt is the enclosing FunctionDef, which is what we # want to add to _stmt_parents, not stmt.parent. This case occurs when # node is an Arguments node (representing varargs or kwargs parameter), # and when node.parent is an Arguments node (other parameters). # See issue #180. _stmt_parents.append(stmt) else: _stmt_parents.append(stmt.parent) return _stmts