Styling resulted in code that isn't parsable.

[balthasars]

Hi there!

Thank you for your ongoing work on this great package!

Dealing with legacy code, I encountered code like this:

styler::style_text(
'whatever <- function(x) {
    if (is.vector(x)){
        {if(is.Date(x)){ mbspalte <- 1}
            }  #Label "seit dd.mm.yyyy"
    }
}
'
)
#> Error in `value[[3L]]()`:
#> ! Styling resulted in code that isn't parsable. This should not happen. Please file a bug report on GitHub (https://github.com/r-lib/styler/issues) using a reprex.

#> Backtrace:
#>      ▆
#>   1. ├─styler::style_text("whatever <- function(x) {\n    if (is.vector(x)){\n        {if(is.Date(x)){ mbspalte <- 1}\n            }  #Label \"seit dd.mm.yyyy\"\n    }\n}\n")
#>   2. │ └─styler (local) transformer(text)
#>   3. │   └─... %>% ...
#>   4. ├─purrr::when(...)
#>   5. └─styler:::parse_transform_serialize_r(...)
#>   6.   └─styler:::verify_roundtrip(text, text_out, parsable_only = !parse_tree_must_be_identical(transformers))
#>   7.     └─rlang::with_handlers(...)
#>   8.       └─base::tryCatch(.expr, error = `<fn>`)
#>   9.         └─base (local) tryCatchList(expr, classes, parentenv, handlers)
#>  10.           └─base (local) tryCatchOne(expr, names, parentenv, handlers[[1L]])
#>  11.             └─value[[3L]](cond)
#>  12.               └─rlang::abort(...)

^{Created on 2022-11-24 with reprex v2.0.2}

Interestingly enough, removing the comment #Label "seit dd.mm.yyyy" resolves this issue.

styler::style_text(
  "whatever <- function(x) {
    if (is.vector(x)){
        {if(is.Date(x)){ mbspalte <- 1}
            }
    }
}
"
)
#> Warning: Could not use colored = TRUE, as the package prettycode is not
#> installed. Please install it if you want to see colored output or see `?
#> print.vertical` for more information.
#> whatever <- function(x) {
#>   if (is.vector(x)) {{ if (is.Date(x)) {
#>     mbspalte <- 1
#>   } }}
#> }

^{Created on 2022-11-24 with reprex v2.0.2}

Thought this might be useful, cheers!

[IndrajeetPatil]

Thanks for reporting, and also illustrating the workaround.

Definitely a bug.

[lorenzwalthert]

I supspect that it has to do with how new lines are added or removed around curly braces. I note that the R parser does not tolerate all ways you can potentially handle these. In addition, it would be useful if the output would also include the code that can't be parsed, instead of just this message.

[IndrajeetPatil]

Slightly more minimal reprex (suitable for testing):

code <- "{{ 
# x 
}}"

styler::style_text(code)
#> Error in `value[[3L]]()`:
#> ! Styling resulted in code that isn't parsable. This should not happen. Please file a bug report on GitHub (https://github.com/r-lib/styler/issues) using a reprex.

^{Created on 2022-11-24 with reprex v2.0.2}

This code is styled to {{ # x }}, which is not valid:

parse(text = "{{ # x }}")
#> Error in parse(text = "{{ # x }}"): <text>:2:0: unexpected end of input
#> 1: {{ # x }}
#>    ^

^{Created on 2022-11-24 with reprex v2.0.2}

[lorenzwalthert]

Thanks guys. Of course, I should have known that line breaks can never be removed when they move code behind a comment...