[DRE-maint] Bug#920953: ruby-haml-rails FTBFS: invalid byte sequence in US-ASCII (ArgumentError)

[Adrian Bunk]

Source: ruby-haml-rails
Version: 1.0.0-1
Severity: serious
Tags: ftbfs

https://buildd.debian.org/status/fetch.php?pkg=ruby-haml-rails&arch=all&ver=1.0.0-1&stamp=1548295203&raw=0

...
┌──────────────────────────────────────────────────────────────────────────────┐
│ Checking Rubygems dependency resolution on ruby2.5                           │
└──────────────────────────────────────────────────────────────────────────────┘

Invalid gemspec in [haml-rails.gemspec]: No such file or directory - git
/usr/lib/ruby/vendor_ruby/gem2deb/metadata.rb:145:in `gsub!': invalid byte sequence in US-ASCII (ArgumentError)
	from /usr/lib/ruby/vendor_ruby/gem2deb/metadata.rb:145:in `block in load_modified_gemspec'
	from /usr/lib/ruby/vendor_ruby/gem2deb/metadata.rb:144:in `each'
	from /usr/lib/ruby/vendor_ruby/gem2deb/metadata.rb:144:in `load_modified_gemspec'
	from /usr/lib/ruby/vendor_ruby/gem2deb/metadata.rb:121:in `load_gemspec'
	from /usr/lib/ruby/vendor_ruby/gem2deb/metadata.rb:34:in `block in initialize'
	from /usr/lib/ruby/vendor_ruby/gem2deb/metadata.rb:33:in `chdir'
	from /usr/lib/ruby/vendor_ruby/gem2deb/metadata.rb:33:in `initialize'
	from /usr/lib/ruby/vendor_ruby/gem2deb/test_runner.rb:77:in `new'
	from /usr/lib/ruby/vendor_ruby/gem2deb/test_runner.rb:77:in `do_check_dependencies'
	from /usr/lib/ruby/vendor_ruby/gem2deb/test_runner.rb:67:in `run_tests'
	from /usr/bin/gem2deb-test-runner:61:in `<main>'
ERROR: Test "ruby2.5" failed. Exiting.
dh_auto_install: dh_ruby --install /<<PKGBUILDDIR>>/debian/ruby-haml-rails returned exit code 1
make: *** [debian/rules:18: binary-indep] Error 1