123 lines
4.4 KiB
Python
123 lines
4.4 KiB
Python
from jedi.parser_utils import get_flow_branch_keyword, is_scope, get_parent_scope
|
|
from jedi.inference.recursion import execution_allowed
|
|
from jedi.inference.helpers import is_big_annoying_library
|
|
|
|
|
|
class Status(object):
|
|
lookup_table = {}
|
|
|
|
def __init__(self, value, name):
|
|
self._value = value
|
|
self._name = name
|
|
Status.lookup_table[value] = self
|
|
|
|
def invert(self):
|
|
if self is REACHABLE:
|
|
return UNREACHABLE
|
|
elif self is UNREACHABLE:
|
|
return REACHABLE
|
|
else:
|
|
return UNSURE
|
|
|
|
def __and__(self, other):
|
|
if UNSURE in (self, other):
|
|
return UNSURE
|
|
else:
|
|
return REACHABLE if self._value and other._value else UNREACHABLE
|
|
|
|
def __repr__(self):
|
|
return '<%s: %s>' % (type(self).__name__, self._name)
|
|
|
|
|
|
REACHABLE = Status(True, 'reachable')
|
|
UNREACHABLE = Status(False, 'unreachable')
|
|
UNSURE = Status(None, 'unsure')
|
|
|
|
|
|
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
|
|
|
|
|
|
def reachability_check(context, value_scope, node, origin_scope=None):
|
|
if is_big_annoying_library(context) \
|
|
or not context.inference_state.flow_analysis_enabled:
|
|
return UNSURE
|
|
|
|
first_flow_scope = get_parent_scope(node, include_flows=True)
|
|
if origin_scope is not None:
|
|
origin_flow_scopes = list(_get_flow_scopes(origin_scope))
|
|
node_flow_scopes = list(_get_flow_scopes(node))
|
|
|
|
branch_matches = True
|
|
for flow_scope in origin_flow_scopes:
|
|
if flow_scope in node_flow_scopes:
|
|
node_keyword = get_flow_branch_keyword(flow_scope, node)
|
|
origin_keyword = get_flow_branch_keyword(flow_scope, origin_scope)
|
|
branch_matches = node_keyword == origin_keyword
|
|
if flow_scope.type == 'if_stmt':
|
|
if not branch_matches:
|
|
return UNREACHABLE
|
|
elif flow_scope.type == 'try_stmt':
|
|
if not branch_matches and origin_keyword == 'else' \
|
|
and node_keyword == 'except':
|
|
return UNREACHABLE
|
|
if branch_matches:
|
|
break
|
|
|
|
# Direct parents get resolved, we filter scopes that are separate
|
|
# branches. This makes sense for autocompletion and static analysis.
|
|
# For actual Python it doesn't matter, because we're talking about
|
|
# potentially unreachable code.
|
|
# e.g. `if 0:` would cause all name lookup within the flow make
|
|
# unaccessible. This is not a "problem" in Python, because the code is
|
|
# never called. In Jedi though, we still want to infer types.
|
|
while origin_scope is not None:
|
|
if first_flow_scope == origin_scope and branch_matches:
|
|
return REACHABLE
|
|
origin_scope = origin_scope.parent
|
|
|
|
return _break_check(context, value_scope, first_flow_scope, node)
|
|
|
|
|
|
def _break_check(context, value_scope, flow_scope, node):
|
|
reachable = REACHABLE
|
|
if flow_scope.type == 'if_stmt':
|
|
if flow_scope.is_node_after_else(node):
|
|
for check_node in flow_scope.get_test_nodes():
|
|
reachable = _check_if(context, check_node)
|
|
if reachable in (REACHABLE, UNSURE):
|
|
break
|
|
reachable = reachable.invert()
|
|
else:
|
|
flow_node = flow_scope.get_corresponding_test_node(node)
|
|
if flow_node is not None:
|
|
reachable = _check_if(context, flow_node)
|
|
elif flow_scope.type in ('try_stmt', 'while_stmt'):
|
|
return UNSURE
|
|
|
|
# Only reachable branches need to be examined further.
|
|
if reachable in (UNREACHABLE, UNSURE):
|
|
return reachable
|
|
|
|
if value_scope != flow_scope and value_scope != flow_scope.parent:
|
|
flow_scope = get_parent_scope(flow_scope, include_flows=True)
|
|
return reachable & _break_check(context, value_scope, flow_scope, node)
|
|
else:
|
|
return reachable
|
|
|
|
|
|
def _check_if(context, node):
|
|
with execution_allowed(context.inference_state, node) as allowed:
|
|
if not allowed:
|
|
return UNSURE
|
|
|
|
types = context.infer_node(node)
|
|
values = set(x.py__bool__() for x in types)
|
|
if len(values) == 1:
|
|
return Status.lookup_table[values.pop()]
|
|
else:
|
|
return UNSURE
|