From: Dr Balwinder S Dheeman <bsd.SANSPAM@...>
Date: 2005-05-10T01:14:37+09:00
Subject: Re: No Thing Here vs Uninitialized and RCR 303

On 05/09/2005 04:21 AM, Bill Atkins wrote:
> This isn't about changing programming habits.  Having nil return nil
> for missing methods can have serious consequences.
> 
> Consider:
> 
>    file = create_new_log_file
>    file.log "here's a bit of information"
> 
> You're expecting this code to log something to a file every time it
> gets called.  But suppose create_new_log_file returns nil, due to some
> mistake you've made while coding it.  No exception is raised, so when
> you run your program, it performs its job appropriately.  You move on.
> 
> Two months later, you urgently need to get information from those
> logs.  But uh-oh - the log files are empty.  Now you're screwed.

irb(main):001:0> file.log 'here is a bit of infromation'
NameError: undefined local variable or method `file' for main:Object
         from (irb):1
irb(main):002:0> file = nil
=> nil
irb(main):003:0> file.log 'here is a bit of infromation'
NoMethodError: undefined method `log' for nil:NilClass
         from (irb):3
irb(main):004:0>

-- 
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