Bug #13073: Hash Key => Proc parse failure

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: 2.4.0p0
• Backport: 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: DONE

[myrrlyn (Alexander Payne)]

A Hash that stores multiple Proc literals causes syntax failures when passed as a method argument. Specifically, this only appears to happen on the second Proc literal in a Hash, not the first.

Minimal test case:

def foo a, h
  [a, h]
end

foo :bar, {
  a: proc do
  end,
  b: proc do
  end
}

Attempting to load this code causes the following error:

SyntaxError: test.rb:8: syntax error, unexpected keyword_do_block, expecting '}'
  b: proc do
            ^

I first encountered this while attempting to run the Middleman gem (version 4.2.0). The specific error is:

/usr/local/lib/ruby/gems/2.4.0/gems/middleman-core-4.2.0/lib/middleman-core/application.rb:194: syntax error, unexpected keyword_do_block, expecting '}' (SyntaxError)
      layout: proc do |file, app|
                     ^
/usr/local/lib/ruby/gems/2.4.0/gems/middleman-core-4.2.0/lib/middleman-core/application.rb:194: syntax error, unexpected '|', expecting '='
   layout: proc do |file, app|
                              ^
/usr/local/lib/ruby/gems/2.4.0/gems/middleman-core-4.2.0/lib/middleman-core/application.rb:197: syntax error, unexpected '}', expecting keyword_end
    }, 'Callbacks that can exclude 
     ^
/usr/local/lib/ruby/gems/2.4.0/gems/middleman-core-4.2.0/lib/middleman-core/application.rb:460: syntax error, unexpected keyword_end, expecting end-of-input

The offending code is visible on GitHub, here.

[myrrlyn (Alexander Payne)]

A Hash that stores multiple Proc literals causes syntax failures when passed as a method argument. Specifically, this only appears to happen on the second Proc literal in a Hash, not the first.

Minimal test case:

def foo a, h
  [a, h]
end

foo :bar, {
  a: proc do
  end,
  b: proc do
  end
}

Attempting to load this code causes the following error:

SyntaxError: test.rb:8: syntax error, unexpected keyword_do_block, expecting '}'
  b: proc do
            ^

Note that simply commenting out the lines for b: proc do \n end cause the file to be successfully parsed.

def foo a, h
  [a, h]
end

foo :bar, {
  a: proc do
  end,
#  b: proc do
#  end
}

I first encountered this while attempting to run the Middleman gem (version 4.2.0). The specific error is:

/usr/local/lib/ruby/gems/2.4.0/gems/middleman-core-4.2.0/lib/middleman-core/application.rb:194: syntax error, unexpected keyword_do_block, expecting '}' (SyntaxError)
      layout: proc do |file, app|
                     ^
/usr/local/lib/ruby/gems/2.4.0/gems/middleman-core-4.2.0/lib/middleman-core/application.rb:194: syntax error, unexpected '|', expecting '='
   layout: proc do |file, app|
                              ^
/usr/local/lib/ruby/gems/2.4.0/gems/middleman-core-4.2.0/lib/middleman-core/application.rb:197: syntax error, unexpected '}', expecting keyword_end
    }, 'Callbacks that can exclude 
     ^
/usr/local/lib/ruby/gems/2.4.0/gems/middleman-core-4.2.0/lib/middleman-core/application.rb:460: syntax error, unexpected keyword_end, expecting end-of-input

The offending code is visible on GitHub, here.

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset r57198.

---

parse.y: preserve cmdarg stack

• parse.y (do_body): preserve cmdarg stack around do/end block.
  [ruby-core:78837] [Bug #13073]

[naruse (Yui NARUSE)]

• Backport changed from 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN to 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: DONE

ruby_2_4 r57837 merged revision(s) 57198.