Single-indent multi-line function definitions

[d-morrison]

The "Good" "Single-indent" example of "Multi-line function definitions" from the tidyverse style guide (https://style.tidyverse.org/functions.html#multi-line-function-definitions) currently generates a lint from indentation_linter:

code <-
'long_function_name <- function(
    a = "a long argument",
    b = "another argument",
    c = "another long argument"
) {
  # As usual code is indented by two spaces.
}'
cat(code)
#> long_function_name <- function(
#>     a = "a long argument",
#>     b = "another argument",
#>     c = "another long argument"
#> ) {
#>   # As usual code is indented by two spaces.
#> }
lintr::lint(code)
#> <text>:2:4: style: [indentation_linter] Indentation should be 2 spaces but is 4 spaces.
#>     a = "a long argument",
#>   ~^

^{Created on 2025-03-10 with reprex v2.1.1}

This occurs both with v3.2.0 from CRAN and commit a2b8d6f from GitHub.

In contrast, moving ) { onto the line of the last argument produces no lint:

code <-
'long_function_name <- function(
    a = "a long argument",
    b = "another argument",
    c = "another long argument") {
  # As usual code is indented by two spaces.
}'
cat(code)
#> long_function_name <- function(
#>     a = "a long argument",
#>     b = "another argument",
#>     c = "another long argument") {
#>   # As usual code is indented by two spaces.
#> }
lintr::lint(code)
#> ℹ No lints found.

^{Created on 2025-03-10 with reprex v2.1.1}

[AshesITR]

Double indentation for argument lists was removed from the tidyverse guide. So to me the first example is expected default behavior?

[d-morrison]

Ah - I didn't realize that those indents had gotten doubled when I set up the reprex (they are un-doubled in the style guide).
I think "Reindent lines" (Ctrl-I) in RStudio still adds the double-indent (c.f. rstudio/rstudio#10752 and rstudio/rstudio#11101).

If double-indentation has been removed from the style guide, should the second example above also throw a lint? It also has double indentation, but currently no lint is thrown. Here's a slightly clearer version:

code <-
'
long_function_name <- function(
    a = "a long argument",
    b = "another argument",
    c = "another long argument") {
  # As usual code is indented by two spaces.
}
'
cat(code)
#> 
#> long_function_name <- function(
#>     a = "a long argument",
#>     b = "another argument",
#>     c = "another long argument") {
#>   # As usual code is indented by two spaces.
#> }
lintr::lint(code)
#> ℹ No lints found.

^{Created on 2025-03-11 with reprex v2.1.1}

[AshesITR]

Yes I agree that could lint.
IMO it's not an indentation lint though, I think the lint should land on ) which should be on a new line since the corresponding ( is last-on-line.

WDYT, @MichaelChirico and @IndrajeetPatil?