Feature #2975
closed
Kernel.warn always writes despite $VERBOSE value
Description
=begin
Kernel.warn always writes despite $VERBOSE value
The RDoc say:
http://www.ruby-doc.org/core/classes/Kernel.html#M005921
warn(msg) => nil
Display the given message (followed by a newline) on STDERR unless warnings are disabled (for example with the -W0 flag).
(from Ruby.h, ver 1.8.6, line 562..564, Language="C" )
void rb_warning __((const char*, ...)); /* reports if -w' specified */ void rb_sys_warning __((const char*, ...)); /* reports if -w' specified /
void rb_warn __((const char, ...)); /* reports always */
In ver 1.8.6, in practice Kernel.warn (and by inclusion,) anyobject's instance method warn, outputs no matter what the setting of $VERBOSE. It then appears to work as though it's calling rb_warn in the core, but the RDoc seems to say it should act like it's calling rb_warning in the core.
This has forced me to make my 'warn' calls work the way they should, by doing this:
Send warning only if in Verbose mode¶
warn('My Informational Message') if $VERBOSE
Send warning unless in Silent mode¶
warn('My Important Message') unless $VERBOSE.nil?
Send warning no matter what Verbose mode¶
warn('My Critical Message that MUST be displayed!')
I'm tired of this workaround:
I think we need something like this overrride, where I define 3 methods,
warn, warn?, warn!
and in addition, I have them return a boolean result (the original warn just returned nil.)
#!ruby warn_ovr.rb
Make Warnings work the way they should.¶
by: Dan Rathbun - 16 MAR 2010 - Palm Bay, FL, USA¶
TERMS: Public Domain, Take it, Use it, Abuse it!¶
module Kernel
alias the old warn method¶
alias_method(:old_warn,:warn)
warn! will always send to $stderr¶
regardless of $VERBOSE setting¶
def warn!(msg)
unless msg.is_a?(String)
raise(TypeError,'String argument expected.',caller(1))
end
$stderr.write(msg + "\n")
return true # no IO error occured
end
warn will now send to $stderr¶
ONLY if $VERBOSE is not Silent mode (nil)¶
def warn(msg)
unless msg.is_a?(String)
raise(TypeError,'String argument expected.',caller(1))
end
unless $VERBOSE.nil?
$stderr.write(msg + "\n")
return true
else
return false
end
end
warn? will send to $stderr¶
ONLY if $VERBOSE is in Verbose mode (true)¶
def warn?(msg)
unless msg.is_a?(String)
raise(TypeError,'String argument expected.',caller(1))
end
if $VERBOSE
$stderr.write(msg + "\n")
return true
else
# We return false if $VERBOSE is nil or false
return false
end
end
end # Kernel
NOTE: The above override script does not override the Module method Kernel.warn, only the instance method. (I could have just run the script in the ObjectSpace without the Kernel wrapper, and added the methods to class Object. Their use either way is the same.)
=end
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