From: "nobu (Nobuyoshi Nakada) via ruby-core" <ruby-core@...>
Date: 2024-05-07T04:03:52+00:00
Subject: [ruby-core:117786] [Ruby master Bug#20465] parse.y adds an extra empty string to the AST

Issue #20465 has been updated by nobu (Nobuyoshi Nakada).


tenderlovemaking (Aaron Patterson) wrote in #note-2:
> It's not a problem for the compiler (of course), but a problem for the language server use case.  Users didn't write `""` there, so consumers of the AST will have to detect and handle this case.  If the AST is supposed to reflect the source document, then I would expect there to _not_ be a `""` node.

I think it should be there, since there is an empty string part before `#`.


----------------------------------------
Bug #20465: parse.y adds an extra empty string to the AST
https://bugs.ruby-lang.org/issues/20465#change-108193

* Author: tenderlovemaking (Aaron Patterson)
* Status: Open
* ruby -v: ruby 3.4.0dev (2024-05-02T15:27:18Z master 7c0cf71049) [arm64-darwin23]
* Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
Given this code:

```ruby
t0 = '\\xc1'
"#{t0}"
```

The AST is like this:

```
$ ./miniruby --dump=parsetree test.rb
###########################################################
## Do NOT use this node dump for any purpose other than  ##
## debug and research.  Compatibility is not guaranteed. ##
###########################################################

# @ NODE_SCOPE (id: 8, line: 1, location: (1,0)-(2,7))
# +- nd_tbl: :t0
# +- nd_args:
# |   (null node)
# +- nd_body:
#     @ NODE_BLOCK (id: 6, line: 1, location: (1,0)-(2,7))
#     +- nd_head (1):
#     |   @ NODE_LASGN (id: 0, line: 1, location: (1,0)-(1,12))*
#     |   +- nd_vid: :t0
#     |   +- nd_value:
#     |       @ NODE_STR (id: 1, line: 1, location: (1,5)-(1,12))
#     |       +- string: "\\xc1"
#     +- nd_head (2):
#         @ NODE_DSTR (id: 4, line: 2, location: (2,0)-(2,7))*
#         +- string: ""
#         +- nd_next->nd_head:
#         |   @ NODE_EVSTR (id: 3, line: 2, location: (2,0)-(2,7))
#         |   +- nd_body:
#         |       @ NODE_LVAR (id: 2, line: 2, location: (2,3)-(2,5))
#         |       +- nd_vid: :t0
#         +- nd_next->nd_next:
#             (null node)
```

There is an empty DSTR.  I don't think that DSTR should be there since it's not part of the source.



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