Nested heredocs are not parsed correctly

[aibaars]

puts <<HERE
  hello #{<<HERE}
  world
HERE
HERE

In the following parse tree the ranges of the heredoc bodies are not right

program [0, 0] - [6, 0])
  method_call [0, 0] - [0, 11])
    method: identifier [0, 0] - [0, 4])
    arguments: argument_list [0, 5] - [0, 11])
      heredoc_beginning [0, 5] - [0, 11])
  heredoc_body [0, 11] - [3, 4])
    interpolation [1, 8] - [1, 17])
      heredoc_beginning [1, 10] - [1, 16])
    heredoc_end [3, 0] - [3, 4])
  heredoc_body [3, 4] - [4, 4])
    heredoc_end [4, 0] - [4, 4])

[aegarbutt-stripe]

I've run into this issue when trying to run semgrep on a ruby file with nested heredocs. (semgrep/semgrep#3151)

When I paste the following into https://tree-sitter.github.io/tree-sitter/playground:

output =
  <<~ABC
    Top
    #{
      <<~DEF
        Middle
      DEF
    }
    Bottom
  ABC

puts output

I get the following output:

program [0, 0] - [13, 0])
  assignment [0, 0] - [1, 8])
    left: identifier [0, 0] - [0, 6])
    right: heredoc_beginning [1, 2] - [1, 8])
  heredoc_body [1, 8] - [9, 5])
    heredoc_content [1, 8] - [3, 4])
    interpolation [3, 4] - [7, 5])
      heredoc_beginning [4, 6] - [4, 12])
      constant [5, 8] - [5, 14])
      constant [6, 6] - [6, 9]). <-- This is the closing DEF of the HEREDOC string
    heredoc_content [7, 5] - [9, 2])
    heredoc_end [9, 2] - [9, 5])
  heredoc_body [9, 5] - [13, 0])
    heredoc_content [9, 5] - [13, 0])
    heredoc_end [13, 0] - [13, 0])

[dumblob]

I have the same issue with bourne shell. Nested heredocs are totally wrongly parsed and thus wrongly highlighted e.g. by neovim.

Do you have any news on the state of heredocs in treesitter?

[aibaars]

@dumblob heredocs are not a treesitter feature. Support for special lexcical things such as heredocs are implemented by scanner.cc. I guess the scanner used tree-sitter-bash has a similar bug as the one of tree-sitter-ruby.