exar...@twistedmatrix.com wrote:
On 12:20 pm, alan.is...@gmail.com wrote:
I think you are missing my point.
I understand it is just a DeprecationWarning.
But **why** should I receive a deprecation warning
when I am **not** using the deprecated practice?
Since I am **not** using the deprecated practice, the
warning is incorrect. (See the class definition above.)
And this incorrect warning affects a lot of people!
You are using the deprecated practice. Attributes are not scoped to a
particular class. There is only one "message" attribute on your
"MyError" instance. It does not belong just to "MyError". It does not
belong just to "Exception". It does not belong just to "BaseException".
It is shared by all of them. Because "BaseException" deprecates
instances of it having a "message" attribute, any instance of any
subclass of "BaseException" which uses this attribute will get the
deprecation warning. Perhaps you weren't intending to use the "message"
attribute as "BaseException" was using it, but this doesn't matter.
There is only one "message" attribute, and "BaseException" already
claimed it, and then deprecated it.
What anyone who is **not** using the deprecated practice
should expect in Python 2.6 is the Py3 behavior. That is
not what we get: we get instead an incorrect deprecation
warning.
Possibly so, but there is no way for the runtime to know that you're not
trying to use the deprecated behavior. All it can tell is that you're
using the deprecated attribute name. Perhaps you can come up with a way
for it to differentiate between these two cases and contribute a patch,
though.
It is sometimes hard to warn exactly when appropriate and impossible for
the default action to satisfy everyone. The developers are, of course,
aware of this. That is why there is a mechanism to turn off particular
warnings. Checkout the extremely flexible warnings module.
tjr
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