[DRE-maint] Bug#802116: ruby-coveralls: FTBFS: `require': cannot load such file -- multi_json (LoadError)

[Chris West (Faux)]

Source: ruby-coveralls
Version: 0.7.0-1
Severity: serious
Justification: fails to build from source
Tags: sid stretch
User: reproducible-builds at lists.alioth.debian.org
Usertags: ftbfs
X-Debbugs-CC: reproducible-builds at lists.alioth.debian.org

Dear Maintainer,

The package fails to build:

Rewriting shebang line of /ruby-coveralls-0.7.0/debian/ruby-coveralls/usr/bin/coveralls

┌──────────────────────────────────────────────────────────────────────────────┐
│ Install Rubygems integration metadata                                        │
└──────────────────────────────────────────────────────────────────────────────┘

generating gemspec at /ruby-coveralls-0.7.0/debian/ruby-coveralls/usr/share/rubygems-integration/all/specifications/coveralls-0.7.0.gemspec
/usr/bin/ruby2.1 /usr/bin/gem2deb-test-runner

┌──────────────────────────────────────────────────────────────────────────────┐
│ Run tests for ruby2.1 from debian/ruby-tests.rb                              │
└──────────────────────────────────────────────────────────────────────────────┘

RUBYLIB=/ruby-coveralls-0.7.0/debian/ruby-coveralls/usr/lib/ruby/vendor_ruby:. ruby2.1 debian/ruby-tests.rb
/usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- multi_json (LoadError)
	from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /ruby-coveralls-0.7.0/debian/ruby-coveralls/usr/lib/ruby/vendor_ruby/coveralls/api.rb:4:in `<class:API>'
	from /ruby-coveralls-0.7.0/debian/ruby-coveralls/usr/lib/ruby/vendor_ruby/coveralls/api.rb:2:in `<module:Coveralls>'
	from /ruby-coveralls-0.7.0/debian/ruby-coveralls/usr/lib/ruby/vendor_ruby/coveralls/api.rb:1:in `<top (required)>'
	from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /ruby-coveralls-0.7.0/debian/ruby-coveralls/usr/lib/ruby/vendor_ruby/coveralls.rb:3:in `<top (required)>'
	from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /ruby-coveralls-0.7.0/spec/spec_helper.rb:35:in `<top (required)>'
	from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /ruby-coveralls-0.7.0/spec/coveralls/coveralls_spec.rb:1:in `<top (required)>'
	from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from debian/ruby-tests.rb:2:in `block in <main>'
	from debian/ruby-tests.rb:2:in `each'
	from debian/ruby-tests.rb:2:in `<main>'
ERROR: Test "ruby2.1" failed. Exiting.
dh_auto_install: dh_ruby --install /ruby-coveralls-0.7.0/debian/ruby-coveralls returned exit code 1
debian/rules:15: recipe for target 'binary' failed

Full build log:
https://reproducible.debian.net/rb-pkg/unstable/amd64/ruby-coveralls.html

-- System Information:
Debian Release: stretch/sid
APT prefers unstable
APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)