Environment

• JRuby version:
  • jruby -v: jruby 9.1.7.0 (2.3.1) 2017-01-11 68056ae Java HotSpot(TM) 64-Bit Server VM 25.73-b02 on 1.8.0_73-b02 +jit [linux-x86_64]
  • No flags or JRUBY_OPTS
• Operating system and platform
  • uname -a: Linux manu-dm 4.4.0-45-generic Proc interface regression #66~14.04.1-Ubuntu SMP Wed Oct 19 15:05:38 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

Expected Behavior

Creating enumerators inside GZipReader blocks should not crash. The simple example below works fine (doesn't crash) on MRI 2.3.0:

# /tmp/local_jump_error.rb
require 'zlib'

# echo | gzip > /tmp/somefile.gz
Zlib::GzipReader.open('/tmp/somefile.gz') do |f|
    e = f.each_line
    # ...
end

Actual Behavior

Instead, a LocalJumpError exception is raised:

LocalJumpError: yield called out of block
                          each at org/jruby/ext/zlib/JZlibRubyGzipReader.java:617
                     each_line at org/jruby/ext/zlib/JZlibRubyGzipReader.java:628
  block in local_jump_error.rb at local_jump_error.rb:6
                          open at org/jruby/ext/zlib/JZlibRubyGzipReader.java:99
                        <main> at local_jump_error.rb:5

Note that using File.open instead of Zlib::GzipReader.open does not raise any error.