Ruby

Bug #1633

Updated by jeremyevans0 (Jeremy Evans) over 5 years ago

=begin 
  
  I don't claim to fully understand this issue, but I'd like to explain some differences between ARGF#close/#skip on 1.8 and 1.9 which seem peculiar. 
 
  If ARGV is empty, ARGF refers to STDIN. On all versions ARGF#close suceeds, but ARGF#closed? returns false on 1.9; true on earlier versions. 
 
      $ ruby86 -ve 'ARGF.close; p ARGF.closed?' 
      ruby 1.8.6 (2009-03-31 patchlevel 368) [i686-linux] 
      true 
 
      $ ruby1.8 -ve 'ARGF.close; p ARGF.closed?' 
      ruby 1.8.7 (2008-08-11 patchlevel 72) [i486-linux] 
      true 
 
      $ ruby -ve 'ARGF.close; p ARGF.closed?' 
      ruby 1.9.2dev (2009-06-14 trunk 23689) [i686-linux] 
      false 
 
  Trying to #close an already closed stream raises an IOError, whereas it didn't on 1.8. Thus, you can no longer cavalierly say ARGF.close; you must instead say ARGF.close unless ARGF.closed?, or precede it with a rescue clause. 
 
      $ ruby86 -ve 'ARGF.close; ARGF.close' file 
      ruby 1.8.6 (2009-03-31 patchlevel 368) [i686-linux] 
 
      $ ruby1.8 -ve 'ARGF.close; ARGF.close' file 
      ruby 1.8.7 (2008-08-11 patchlevel 72) [i486-linux] 
 
      $ ruby -ve 'ARGF.close; ARGF.close' file 
      ruby 1.9.2dev (2009-06-14 trunk 23689) [i686-linux] 
      -e:1:in `close': closed stream (IOError) 
 	 from -e:1:in `close' 
 	 from -e:1:in `<main>' 
 
  This behaviour impacts ARGF#skip on 1.9, too. Worse, the error message is misleading due to refrencing 'close'; a method that the user did not invoke, thus can't be held responsible for the failure of. 
 
      $ ruby86 -ve 'ARGF.read; ARGF.skip' file 
      ruby 1.8.6 (2009-03-31 patchlevel 368) [i686-linux] 
     
      $ ruby1.8 -ve 'ARGF.read; ARGF.skip' file 
      ruby 1.8.7 (2008-08-11 patchlevel 72) [i486-linux] 
 
      $ ruby -ve 'ARGF.read; ARGF.skip' file 
      ruby 1.9.2dev (2009-06-14 trunk 23689) [i686-linux] 
      -e:1:in `close': closed stream (IOError) 
 	 from -e:1:in `skip' 
 	 from -e:1:in `<main>' 
 
  Tangentially, a similarly odd exception is raised on all versions if ARGF#skip is invoked without files to skip to: 
 
      $ ruby -ve 'ARGF.skip' file 
      ruby 1.9.2dev (2009-06-14 trunk 23689) [i686-linux] 
      -e:1:in `skip': undefined method `close' for nil:NilClass (NoMethodError) 
 	 from -e:1:in `<main>' 
 
  Given that ARGF is likely to contain a variable number of files, it may be easier if these methods returned nil when there are no more files. This would retain backward compatibility, and reduce error handling logic. 
 
 =end 
 

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