def make_fake_object(cls: type, varname: str) -> object:
constructor = get_smt_proxy_type(cls)
try:
proxy = constructor()
except TypeError as e:
# likely the type has a __new__ that expects arguments
raise CrosshairUnsupported(f'Unable to proxy {name_of_type(cls)}: {e}')
for name, typ in get_type_hints(cls).items():
origin = getattr(typ, '__origin__', None)
if origin is Callable:
continue
value = proxy_for_type(
typ, varname + '.' + name + context_statespace().uniq())
object.__setattr__(proxy, name, value)
return proxy
def get_smt_proxy_type(cls: type) -> type:
if issubclass(cls, SmtProxyMarker):
return cls
global _SMT_PROXY_TYPES
cls_name = name_of_type(cls)
if cls not in _SMT_PROXY_TYPES:
def symbolic_init(self):
self.__class__ = cls
class_body = { '__init__': symbolic_init }
try:
proxy_cls = type(cls_name + '_proxy', (SmtProxyMarker, cls), class_body)
except TypeError as e:
if 'is not an acceptable base type' in str(e):
raise CrosshairUnsupported(f'Cannot subclass {cls_name}')
else:
raise
_SMT_PROXY_TYPES[cls] = proxy_cls
return _SMT_PROXY_TYPES[cls]
def __exit__(self, exc_type, exc_value, tb):
if isinstance(exc_value, (PostconditionFailed, IgnoreAttempt)):
if isinstance(exc_value, PostconditionFailed):
# Postcondition : although this indicates a problem, it's with a
# subroutine; not this function.
# Usualy we want to ignore this because it will be surfaced more locally
# in the subroutine.
debug(
f'Ignoring based on internal failed post condition: {exc_value}'
)
self.ignore = True
self.analysis = CallAnalysis()
return True
if isinstance(exc_value, self.expected_exceptions):
debug(f'Hit expected exception: {exc_value}')
self.ignore = True
self.analysis = CallAnalysis(VerificationStatus.CONFIRMED)
return True
if isinstance(exc_value, TypeError):
exc_str = str(exc_value)
if ('SmtStr' in exc_str or 'SmtInt' in exc_str
or 'SmtFloat' in exc_str
or 'expected string or bytes-like object' in exc_str):
# Ideally we'd attempt literal strings after encountering this.
# See https://github.com/pschanely/CrossHair/issues/8
debug('Proxy intolerace at: ', traceback.format_exc())
raise CrosshairUnsupported('Detected proxy intolerance: ' +
exc_str)
if isinstance(exc_value,
(UnexploredPath, CrosshairInternal, z3.Z3Exception)):
return False # internal issue: re-raise
if isinstance(
exc_value,
BaseException): # TODO: should this be "Exception" instead?
# Most other issues are assumed to be user-level exceptions:
self.user_exc = (exc_value,
traceback.extract_tb(sys.exc_info()[2]))
self.analysis = CallAnalysis(VerificationStatus.REFUTED)
return True # suppress user-level exception
return False # re-raise resource and system issues