[ruby-core:56239] [ruby-trunk - Bug #8625][Assigned] IO#read(len, buf) shortens buf even if data is not read actually

Issue #8625 has been updated by Glass_saga (Masaki Matsushita).

Status changed from Open to Assigned
Assignee set to nobu (Nobuyoshi Nakada)

Nakada-san, what do you think?
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Bug #8625: IO#read(len, buf) shortens buf even if data is not read actually
https://bugs.ruby-lang.org/issues/8625#change-40730

Author: no6v (Nobuhiro IMAI)
Status: Assigned
Priority: Normal
Assignee: nobu (Nobuyoshi Nakada)
Category: core
Target version: 
ruby -v: ruby 2.1.0dev (2013-07-11 trunk 41923) [x86_64-linux]
Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN


=begin
By r34580, IO#read(len, buf) does not expand buf until data is read actually,
but it still shortens if the original buf size is greater than len.
Is this an intended behavior?

 def m(s)
   IO.pipe do |r, w|
     t = Thread.new{r.read(2, s)}
     Thread.pass until t.stop?
     t.kill
     t.value
   end
 end
 
 (1..3).each do |len|
   s = "x" * len
   s # => "x", "xx", "xxx"
   m(s)
   s # => "x", "xx", "xx"
 end
=end



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