Re: nil messaging? Is it safe?
Re: nil messaging? Is it safe?
- Subject: Re: nil messaging? Is it safe?
- From: Jonathan Wight <email@hidden>
- Date: Thu, 26 Sep 2002 21:48:48 -0500
On 09/26/2002 20:20, "Ondra Cada" <email@hidden> wrote:
>
On Friday, September 27, 2002, at 01:19 , Jonathan Wight wrote:
>
>
> Which reminds me - I find the fact that the runtime effectively ignores
>
> messages to nil/NULL to be a source of many hard to trace errors. Is it
>
> possible to set the runtime or perhaps GDB up so that it'll break if you
>
> attempt to send a message to nil?
>
>
No, since it is a *VERY* common trick.
>
>
More precisely: of course you can do that, but if you try, you'll return
>
to the original behaviour as fast as possible. Anybody sends messages to
>
nil (assuming nothing happens) *VERY* frequently.
I understand that - and appreciate it.
The kind of bug I'm talking about is where a method returns an object and
then you call methods on the returned object. If the original method fails
and returns null (and you've neglected to test for null) the subsequent
methods are not going to be executed. Instead of having to hunt this bug
down by hand, I'd love to be able to switch on a environment variable and
have all attempts to send messages to NULL logged.
I have no problems with the current behaviour, sending messages to NULL
makes a lot of sense in most circumstances (esp. lazy releases). I'd just
like to know when it's happening and I'm not expecting it.
Jon.
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