Handle endless ranges

[palkan]

Ruby version: 2.6.3
Unparser: 0.4.5
Parser: 2.6.3

This patch fixes the following error:

Unparser.unparse(Parser::CurrentRuby.parse("r = (1..)"))
#=> NoMethodError: undefined method `type' for nil:NilClass

Couldn't find a quick way to add tests for this change 🤷🏻‍♂️ (has been used and tests here).

[mbj]

@palkan Thanks.

I'm surprised this is not found when round tripping rubyspec (which is part of the CI). I need to expand the corpus to catch these.

I'll add the tests in a fresh PR.

[mbj]

@palkan any idea on a project that covers more ruby syntax?

The alternative idea was to hook the parser tests and roundtrip its tests. that is probably the gold standard.

[palkan]

I'm surprised this is not found when round tripping rubyspec

I found that rubyspec is far from complete) I had to write my own tests for this syntax.

any idea on a project that covers more ruby syntax?

Probably, some other transformers/analyzers, e.g., RuboCop. Though it mostly uses eval.
Ruby's own test suite also relies on eval.

Rails covers a lot but it's huge 🙂

[mbj]

Rails covers a lot but it's huge

Unparser is quite fast (in sense of enough). So its probably a good corpus target. Intercepting the ruby fragments parser uses during may also be an option.

[mbj]

I'm closing this in favor of #139