twisted.internet.defer.Deferred.errback(self, fail=None)
method documentationtwisted.internet.defer.Deferred
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Run all error callbacks that have been added to this Deferred
.
Each callback will have its result passed as the first argument to the next; this way, the callbacks act as a 'processing chain'. Also, if the error-callback returns a non-Failure or doesn't raise an Exception
, processing will continue on the *success*-callback chain.
If the argument that's passed to me is not a failure.Failure
instance, it will be embedded in one. If no argument is passed, a failure.Failure
instance will be created based on the current traceback stack.
Passing a string as `fail' is deprecated, and will be punished with a warning message.
An instance of Deferred
may only have either callback
or errback
called on it, and only once.
Parameters | fail | The Failure object which will be passed to the first errback added to this Deferred (via addErrback ). Alternatively, a Exception instance from which a Failure will be constructed (with no traceback) or None to create a Failure instance from the current exception state (with a traceback). |
Raises | AlreadyCalledError | If callback or errback has already been called on this Deferred . |
NoCurrentExceptionError | If fail is None but there is no current exception state. |