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class CtxMgr:
def __enter__(self):
print("__enter__")
return self
def __exit__(self, a, b, c):
print("__exit__", repr(a), repr(b))
with CtxMgr() as a:
print(isinstance(a, CtxMgr))
try:
with CtxMgr() as a:
raise ValueError
except ValueError:
print("ValueError")
class CtxMgr2:
def __enter__(self):
print("__enter__")
return self
def __exit__(self, a, b, c):
print("__exit__", repr(a), repr(b))
return True
try:
with CtxMgr2() as a:
raise ValueError
print("No ValueError2")
except ValueError:
print("ValueError2")
# These recursive try-finally tests are attempt to get some interpretation
# of last phrase in http://docs.python.org/3.4/library/dis.html#opcode-WITH_CLEANUP
# "If the stack represents an exception, and the function call returns a 'true'
# value, this information is "zapped" and replaced with a single WHY_SILENCED
# to prevent END_FINALLY from re-raising the exception. (But non-local gotos
# will still be resumed.)"
print("===")
with CtxMgr2() as a:
try:
try:
raise ValueError
print("No ValueError3")
finally:
print("finally1")
finally:
print("finally2")
print("===")
try:
try:
with CtxMgr2() as a:
try:
try:
raise ValueError
print("No ValueError3")
finally:
print("finally1")
finally:
print("finally2")
finally:
print("finally3")
finally:
print("finally4")
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