dev.args ignored unless wrapped in a list with device names as element names, even with only one device

[petrbouchal]

When setting a device document-wide, the dev.args only has effect if passed in the form of dev.args = list(device_name = list(option_1 = "x")); when set as dev.args = list(option_1 = "x"), the argument is ignored.

This applies also when only one device is set in dev.

This is surprising given that the documenation states the former usage as necessary only when multiple devices are used (and can be interpreted that when multiple devices are set, the dev.args list would apply to both devices unless set as list(dev_1 = list(...), dev_2 = list(...))).

The reprex below explores the resulting files when

1. dev.args is set without the list structure (dev.args is ignored)
2. dev.args is a list with one element, named after the single device (this works)
3. the same arguments are passed to the device directly, for confirmation

Reprex

---
title: "dev.args passed to svglite"
output: 
  html_document:
    self_contained: false
---

```{r setup, include=FALSE}
library(ggplot2)
library(svglite)
```

## Set `dev.args` as named list for the single device

```{r set-devargs-using-list, include=FALSE}
knitr::opts_chunk$set(echo = TRUE, dev = "svglite",
                      comment = "",
                      dev.args = list(svglite = list(web_fonts = list("https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:ital,wght@0,400;0,700;1,400;1,700&display=swap",
                                  "https://fonts.googleapis.com/css2?family=IBM+Plex+Sans+Condensed:ital,wght@0,400;0,700;1,400;1,700&display=swap"))))
```

### Make plot

```{r}
plt <- ggplot(mtcars) +
  annotate("text", label = "FFf gjfsgd fdshfdsk", x = .5, y = .5, family = "IBM Plex Sans", size = 12)
```

### Render plot

```{r list}
plt
```

### Inspect resulting file

Note the font-related lines that have appeared on lines 5-6 because the argument has been passed through `dev.args`

```{r}
readLines("svgtest_files/figure-html/list-1.svg", n = 15)
```

## Now  set `dev.args` as a list of options

```{r set-devargs-without-list}
knitr::opts_chunk$set(echo = TRUE, dev = "svglite",
                      comment = "",
                      dev.args = list(web_fonts = list("https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:ital,wght@0,400;0,700;1,400;1,700&display=swap",
                                  "https://fonts.googleapis.com/css2?family=IBM+Plex+Sans+Condensed:ital,wght@0,400;0,700;1,400;1,700&display=swap")))

```

### Render file

```{r generate-svg-no-list}
plt
```

Inspect resulting file - note no font-related lines here

```{r}
readLines("svgtest_files/figure-html/no-list-1.svg", n = 15)
```

## Pass the argument directly to the device

```{r}
svglite("svgtest.svg",
        web_fonts = list("https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:ital,wght@0,400;0,700;1,400;1,700&display=swap",
                                  "https://fonts.googleapis.com/css2?family=IBM+Plex+Sans+Condensed:ital,wght@0,400;0,700;1,400;1,700&display=swap"))
plt
dev.off()
```

### Inspect the file

Again, the arguments have an effect

```{r}
readLines("svgtest.svg", n = 15)
```

Same without the argument

```{r}
svglite("svgtest-noarg.svg")
plt
dev.off()
```

### Inspect the file

Here, the font lines do not appear, as expected

```{r}
readLines("svgtest-noarg.svg", n = 15)
```

Session info

R version 4.2.1 (2022-06-23)
Platform: aarch64-apple-darwin20 (64-bit)
Running under: macOS Ventura 13.3, RStudio 2023.3.0.323

Locale: en_US.UTF-8 / en_US.UTF-8 / en_US.UTF-8 / C / en_US.UTF-8 / en_US.UTF-8

Package version:
  askpass_1.1       base64enc_0.1.3   brew_1.0.7        brio_1.1.3        bslib_0.4.0       cachem_1.0.6      callr_3.7.0       cli_3.6.0         clipr_0.8.0      
  clisymbols_1.2.0  commonmark_1.8.0  compiler_4.2.1    cpp11_0.4.3       crayon_1.5.2      credentials_1.3.2 curl_5.0.0        desc_1.4.2        devtools_2.4.3   
  diffobj_0.3.5     digest_0.6.31     ellipsis_0.3.2    evaluate_0.20     fansi_1.0.3       fastmap_1.1.0     fs_1.6.1          gert_1.9.0        gh_1.3.1         
  gitcreds_0.1.2    glue_1.6.2        graphics_4.2.1    grDevices_4.2.1   highr_0.10        htmltools_0.5.4   httr_1.4.4        ini_0.3.1         jquerylib_0.1.4  
  jsonlite_1.8.0    knitr_1.42.3      lifecycle_1.0.3   magrittr_2.0.3    memoise_2.0.1     methods_4.2.1     mime_0.12         openssl_2.0.3     pillar_1.8.1     
  pkgbuild_1.3.1    pkgconfig_2.0.3   pkgload_1.2.4     praise_1.0.0      prettyunits_1.1.1 processx_3.6.1    prompt_1.0.1      ps_1.7.1          purrr_1.0.1      
  R6_2.5.1          rappdirs_0.3.3    rcmdcheck_1.4.0   rematch2_2.1.2    remotes_2.4.2     reprex_2.0.2      rlang_1.0.6       rmarkdown_2.16    roxygen2_7.2.1   
  rprojroot_2.0.3   rstudioapi_0.14   rversions_2.1.1   sass_0.4.2        sessioninfo_1.2.2 stats_4.2.1       stringi_1.7.8     stringr_1.5.0     sys_3.4          
  testthat_3.1.6    tibble_3.1.8      tinytex_0.42      tools_4.2.1       usethis_2.1.6     utf8_1.2.2        utils_4.2.1       vctrs_0.5.2       waldo_0.4.0      
  whisker_0.4       withr_2.5.0       xfun_0.37         xml2_1.3.3        xopen_1.0.0       yaml_2.3.7        zip_2.2.2        

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[yihui]

Should be fixed now. Thanks for the report!

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