From: Kornelius Kalnbach <murphy@...>
Date: 2010-04-12T02:33:41+09:00
Subject: [ruby-core:29453] Re: [Bug #2731](Rejected) FileUtils.copy prints error message in $DEBUG mode when destination doesn't exist

On 11.04.10 16:08, Yusuke Endoh wrote:
> You say, library must not use an exception for internal implementation?
> The convension is uneasy and too uncomfortable for library authors.
> 
> In old convension, an exception might be for exceptional condition.
> But currently, it has many use cases not only to represent exceptional
> condition but also to represent normal condition (e.g., StopIteration),
> to control execution (e.g., DSL), etc.
You're right. I agree that it's not a bug, more like an inconvenient
behavior. The patch might still be an improvement.

The only workaround I know is:

  debug, $DEBUG = $DEBUG, false
  FileUtils.copy source, destination
  $DEBUG = debug

I don't like such constructs because they look ugly (aka "noise").

> So this is not a bug and I close the ticket.
> Rather, we should reconsider the purpose and behavior of $DEBUG.
> Currently, it is worthless in effect.
Spontaneous idea: Setting $DEBUG to an Exception class or an array of
such classes to specify which exception you want to debug. Improving
Rubys debugging capabilities can't hurt.

[murphy]