[DRE-maint] Bug#888164: ruby-packable: FTBFS on ruby2.5: Illegal seek @ rb_io_tell

[Chris West (Faux)]

Source: ruby-packable
Version: 1.3.8-1
Severity: important
User: debian-ruby at lists.debian.org
Usertags: ruby2.5

Dear Maintainer,

This package fails to build against ruby2.5. Soon, there will
be a transition to ruby2.5, and this package will FTBFS in sid.

There may be some details on the wiki about common problems:
https://wiki.debian.org/Teams/Ruby/Ruby25Transition

Build log excerpt:


┌──────────────────────────────────────────────────────────────────────────────┐
│ Run tests for ruby2.3 from debian/ruby-test-files.yaml                       │
└──────────────────────────────────────────────────────────────────────────────┘

RUBYLIB=/build/ruby-packable-1.3.8/debian/ruby-packable/usr/lib/ruby/vendor_ruby:. GEM_PATH=debian/ruby-packable/usr/share/rubygems-integration/all:/root/.gem/ruby/2.3.0:/var/lib/gems/2.3.0:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.3.0:/usr/share/rubygems-integration/2.3.0:/usr/share/rubygems-integration/all ruby2.3 -ryaml -e YAML.load_file\(\"debian/ruby-test-files.yaml\"\).each\ \{\ \|f\|\ require\ f\ \}
Run options: --seed 55512

# Running:

................/build/ruby-packable-1.3.8/debian/ruby-packable/usr/lib/ruby/vendor_ruby/packable/extensions/io.rb:57: warning: Enumerator.new without a block is deprecated; use Object#to_enum
.

Finished in 0.006436s, 2641.5416 runs/s, 10721.5511 assertions/s.

17 runs, 69 assertions, 0 failures, 0 errors, 0 skips
/usr/bin/ruby2.5 /usr/bin/gem2deb-test-runner

┌──────────────────────────────────────────────────────────────────────────────┐
│ Run tests for ruby2.5 from debian/ruby-test-files.yaml                       │
└──────────────────────────────────────────────────────────────────────────────┘

RUBYLIB=/build/ruby-packable-1.3.8/debian/ruby-packable/usr/lib/ruby/vendor_ruby:. GEM_PATH=debian/ruby-packable/usr/share/rubygems-integration/all:/root/.gem/ruby/2.5.0:/var/lib/gems/2.5.0:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0:/usr/share/rubygems-integration/2.5.0:/usr/share/rubygems-integration/all ruby2.5 -ryaml -e YAML.load_file\(\"debian/ruby-test-files.yaml\"\).each\ \{\ \|f\|\ require\ f\ \}
/usr/lib/ruby/vendor_ruby/backports/1.8.7/fixnum/div.rb:1: warning: constant ::Fixnum is deprecated
/usr/lib/ruby/vendor_ruby/backports/1.8.7/fixnum/fdiv.rb:1: warning: constant ::Fixnum is deprecated
/usr/lib/ruby/vendor_ruby/backports/2.1.0/bignum/bit_length.rb:1: warning: constant ::Bignum is deprecated
/usr/lib/ruby/vendor_ruby/backports/2.1.0/fixnum/bit_length.rb:1: warning: constant ::Fixnum is deprecated
/build/ruby-packable-1.3.8/debian/ruby-packable/usr/lib/ruby/vendor_ruby/packable/extensions/io.rb:86:in `pos': Illegal seek @ rb_io_tell - <STDOUT> (Errno::ESPIPE)
	from /build/ruby-packable-1.3.8/debian/ruby-packable/usr/lib/ruby/vendor_ruby/packable/extensions/io.rb:86:in `pack_and_write'
	from /build/ruby-packable-1.3.8/debian/ruby-packable/usr/lib/ruby/vendor_ruby/packable/extensions/io.rb:62:in `write_with_packing'
	from /usr/lib/ruby/vendor_ruby/minitest.rb:580:in `puts'



Full build log:
https://rbuild.fau.xxx/2018-01-23/ruby-packable.log

Please fix it!

Cheers,
Chris.