corruption: backout changeset 49fd21f32695 (issue6528)
inverting the parent is masking copy information leading to bad content being
fetched and bad status result.
Since 49fd21f32695, exchange can actively swap these parent corrupting existing
changesets and triggering the corruption.
Data corruption are considered critical so backing this out and doing and
unscheduled release seems in order.
Differential Revision: https://phab.mercurial-scm.org/D10995
from __future__ import absolute_import, print_function
from mercurial import extensions
def genwrapper(x):
def f(orig, *args, **kwds):
return [x] + orig(*args, **kwds)
f.x = x
return f
def getid(wrapper):
return getattr(wrapper, 'x', '-')
wrappers = [genwrapper(i) for i in range(5)]
class dummyclass(object):
def getstack(self):
return ['orig']
dummy = dummyclass()
def batchwrap(wrappers):
for w in wrappers:
extensions.wrapfunction(dummy, 'getstack', w)
print('wrap %d: %s' % (getid(w), dummy.getstack()))
def batchunwrap(wrappers):
for w in wrappers:
result = None
try:
result = extensions.unwrapfunction(dummy, 'getstack', w)
msg = str(dummy.getstack())
except (ValueError, IndexError) as e:
msg = e.__class__.__name__
print('unwrap %s: %s: %s' % (getid(w), getid(result), msg))
batchwrap(wrappers + [wrappers[0]])
batchunwrap(
[
(wrappers[i] if i is not None and i >= 0 else None)
for i in [3, None, 0, 4, 0, 2, 1, None]
]
)
wrap0 = extensions.wrappedfunction(dummy, 'getstack', wrappers[0])
wrap1 = extensions.wrappedfunction(dummy, 'getstack', wrappers[1])
# Use them in a different order from how they were created to check that
# the wrapping happens in __enter__, not in __init__
print('context manager', dummy.getstack())
with wrap1:
print('context manager', dummy.getstack())
with wrap0:
print('context manager', dummy.getstack())
# Bad programmer forgets to unwrap the function, but the context
# managers still unwrap their wrappings.
extensions.wrapfunction(dummy, 'getstack', wrappers[2])
print('context manager', dummy.getstack())
print('context manager', dummy.getstack())
print('context manager', dummy.getstack())
# Wrap callable object which has no __name__
class callableobj(object):
def __call__(self):
return ['orig']
dummy.cobj = callableobj()
extensions.wrapfunction(dummy, 'cobj', wrappers[0])
print('wrap callable object', dummy.cobj())