import inspect, re
import config, testing
from sqlalchemy import orm
__all__ = 'mapper',
_whitespace = re.compile(r'^(\s+)')
def _find_pragma(lines, current):
m = _whitespace.match(lines[current])
basis = m and m.group() or ''
for line in reversed(lines[0:current]):
if 'testlib.pragma' in line:
return line
m = _whitespace.match(line)
indent = m and m.group() or ''
# simplistic detection:
# >> # testlib.pragma foo
# >> center_line()
if indent == basis:
break
# >> # testlib.pragma foo
# >> if fleem:
# >> center_line()
if line.endswith(':'):
break
return None
def _make_blocker(method_name, fallback):
"""Creates tripwired variant of a method, raising when called.
To excempt an invocation from blockage, there are two options.
1) add a pragma in a comment::
# testlib.pragma exempt:methodname
offending_line()
2) add a magic cookie to the function's namespace::
__sa_baremethodname_exempt__ = True
...
offending_line()
another_offending_lines()
The second is useful for testing and development.
"""
if method_name.startswith('__') and method_name.endswith('__'):
frame_marker = '__sa_%s_exempt__' % method_name[2:-2]
else:
frame_marker = '__sa_%s_exempt__' % method_name
pragma_marker = 'exempt:' + method_name
def method(self, *args, **kw):
frame_r = None
try:
frame = inspect.stack()[1][0]
frame_r = inspect.getframeinfo(frame, 9)
module = frame.f_globals.get('__name__', '')
type_ = type(self)
pragma = _find_pragma(*frame_r[3:5])
exempt = (
(not module.startswith('sqlalchemy')) or
(pragma and pragma_marker in pragma) or
(frame_marker in frame.f_locals) or
('self' in frame.f_locals and
getattr(frame.f_locals['self'], frame_marker, False)))
if exempt:
supermeth = getattr(super(type_, self), method_name, None)
if (supermeth is None or
getattr(supermeth, 'im_func', None) is method):
return fallback(self, *args, **kw)
else:
return supermeth(*args, **kw)
else:
raise AssertionError(
"%s.%s called in %s, line %s in %s" % (
type_.__name__, method_name, module, frame_r[1], frame_r[2]))
finally:
del frame
method.__name__ = method_name
return method
def mapper(type_, *args, **kw):
forbidden = [
('__hash__', 'unhashable', lambda s: id(s)),
('__eq__', 'noncomparable', lambda s, o: s is o),
('__ne__', 'noncomparable', lambda s, o: s is not o),
('__cmp__', 'noncomparable', lambda s, o: object.__cmp__(s, o)),
('__le__', 'noncomparable', lambda s, o: object.__le__(s, o)),
('__lt__', 'noncomparable', lambda s, o: object.__lt__(s, o)),
('__ge__', 'noncomparable', lambda s, o: object.__ge__(s, o)),
('__gt__', 'noncomparable', lambda s, o: object.__gt__(s, o)),
('__nonzero__', 'truthless', lambda s: 1), ]
if isinstance(type_, type) and type_.__bases__ == (object,):
for method_name, option, fallback in forbidden:
if (getattr(config.options, option, False) and
method_name not in type_.__dict__):
setattr(type_, method_name, _make_blocker(method_name, fallback))
return orm.mapper(type_, *args, **kw)
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