[Twisted-Python] Appropriate exception for AMP types receiving garbage?

[Laurens Van Houtven]

How about something like {_error: 1, _error_code: BAD_ARGUMENT_VALUE, ...}?


I was writing something to constrain AMP Argument's in- and output values:

https://github.com/lvh/txampext/blob/master/txampext/constrained.py

... and my users getting a real exception as opposed to a disconnected
transport would be nice :)

Any ticket suggestions welcome.



On Thu, Dec 27, 2012 at 8:02 AM, Glyph <glyph at twistedmatrix.com> wrote:

> On Dec 26, 2012, at 1:43 PM, Laurens Van Houtven <_ at lvh.cc> wrote:
>
> I'm writing a custom AMP type. I noticed that when writing the unit test
> for garbage input, I didn't really know what exception to check for.
>
> I couldn't find any place where this was formally defined, so I checked
> for implementation behavior. Boolean explicitly raises TypeError. Integer
> raises ValueError, but that appears to only be an implementation detail of
> int.
>
> It could also be that it doesn't matter at all, but it does seem a little
> strange that Integer and Boolean raise different exceptions when fed
> garbage...
>
>
> Hey Laurens,
>
> This is basically a feature request :).  There's no particular defined
> error type for argument parse errors in AMP.  It's not a bad feature
> though.  The exception also doesn't go anywhere useful - the only contract
> is basically that it'll bubble up and break the connection if you get some
> bad data.  A more sophisticated and trappable / trackable way to propagate
> this sort of error would be useful.
>
> (I would personally consider it a compatible change if the behavior of the
> error cases changed here, on the grounds that anything that uncontrollably
> logs a traceback in response to network input is a gross spec violation of
> a sort.  Maybe we should add an explicit exemption for that case.)
>
> -glyph
>
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>


-- 
cheers
lvh
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