[DRE-maint] Bug#892460: ruby-parslet: FTBFS and Debci failure with Ruby 2.5

[Adrian Bunk]

Source: ruby-parslet
Version: 1.8.2-1
Severity: serious

https://ci.debian.net/packages/r/ruby-parslet/unstable/amd64/
https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/ruby-parslet.html

...
Failures:

  1) Regression on example/mathn.rb runs successfully
     Failure/Error: io.read.strip.should == File.read(name).strip

       expected: "it terminates before we require mathn\nrequiring mathn now\nand trying again (will hang without the fix)\nokay!"
            got: "it terminates before we require mathn\nrequiring mathn now" (using ==)
       Diff:
       @@ -1,5 +1,3 @@
        it terminates before we require mathn
        requiring mathn now
       -and trying again (will hang without the fix)
       -okay!
     # ./spec/acceptance/examples_spec.rb:25:in `block (5 levels) in <top (required)>'
     # ./spec/acceptance/examples_spec.rb:21:in `any?'
     # ./spec/acceptance/examples_spec.rb:21:in `block (4 levels) in <top (required)>'

Finished in 1 minute 1.22 seconds (files took 8.01 seconds to load)
436 examples, 1 failure

Failed examples:

rspec ./spec/acceptance/examples_spec.rb[1:3:1] # Regression on example/mathn.rb runs successfully

/usr/bin/ruby2.5 /usr/bin/rspec --pattern ./spec/\*\*/\*_spec.rb --format documentation failed
ERROR: Test "ruby2.5" failed. Exiting.
dh_auto_install: dh_ruby --install /build/1st/ruby-parslet-1.8.2/debian/ruby-parslet returned exit code 1
make: *** [debian/rules:6: binary] Error 1