Case statements not working correctly

[MichaelHoste]

We found some issues with case/when statements when parsing ERB templates:

What doesn't work

erb_content = <<~EOS
  <% case 1 %>
  <% when 1 %>foo!
  <% end %>
EOS

src = ERB.new(erb_content).src

# #coding:UTF-8
# _erbout = +'';  case 1 ; _erbout.<< "\n".freeze
# ;  when 1 ; _erbout.<< "foo!\n".freeze
# ;  end ; _erbout.<< "\n".freeze
# ; _erbout

eval(src)

# (eval):2: syntax error, unexpected local variable or method, expecting `when' (SyntaxError)
# ...erbout = +'';  case 1 ; _erbout.<< "\n".freeze
# ...                        ^~~~~~~
# (eval):3: syntax error, unexpected `when', expecting end-of-input
# ;  when 1 ; _erbout.<< "foo!\n".free...
#    ^~~~

What works

erb_content = <<~EOS
  <% case 1 
  when 1 %>foo!
  <% end %>
EOS

src = ERB.new(erb_content).src

# #coding:UTF-8
# _erbout = +'';  case 1 
# when 1 ; _erbout.<< "foo!\n".freeze
# ;  end ; _erbout.<< "\n".freeze
# ; _erbout

eval(src)

# "foo!\n\n"

It was tested on Ruby 3.0.3 and 2.7.2

[k0kubun]

I'm not sure if we've ever supported it. Unlike Haml, ERB doesn't do anything clever whether you embed case-when or not. You have to carefully write your template or choose a proper option to make it work. e.g. This should work:

erb_content = <<~EOS
  <% case 1 %>
  <% when 1 %>foo!
  <% end %>
EOS

src = ERB.new(erb_content, trim_mode: '>').src

[MichaelHoste]

Thank you for looking at this.

[sandstrom]

For reference, here are some other threads on this:

• https://gist.github.com/davidphasson/91613
• https://stackoverflow.com/questions/5282585/syntaxerror-using-case-expression-on-sinatra-1-2-0-and-ruby-1-9-2