libcurl error when using htmlwidgets::saveWidget along with plotly::partial_bundle without an internet connection

Running the ?plotly::partial_bundle example without an internet connection available results in the below error.
I think it used to work without accessing https://cdn.plot.ly ?
As a workaround I'm now using curl::has_internet to check whether I can use partial_bundle.

Example:

library(plotly)
p <- plot_ly(x = 1:10, y = 1:10) %>% add_markers()
save_widget <- function(p, f) {
  owd <- setwd(dirname(f))
  on.exit(setwd(owd))
  htmlwidgets::saveWidget(p, f)
  mb <- round(file.info(f)$size / 1e6, 3)
  message("File is: ", mb," MB")
}
f1 <- tempfile(fileext = ".html")
f2 <- tempfile(fileext = ".html")
save_widget(p, f1)
save_widget(partial_bundle(p), f2)

Error:

Error in curl::curl_download(paste0("https://cdn.plot.ly/", bundle_script),  : 
  Could not resolve hostname [cdn.plot.ly]:
Could not resolve host: cdn.plot.ly
11.
stop(e)
10.
raise_libcurl_error(6L, "Could not resolve hostname", "Could not resolve host: cdn.plot.ly",
"https://cdn.plot.ly/plotly-basic-2.25.2.min.js", NULL)
9.
curl::curl_download(paste0("https://cdn.plot.ly/", bundle_script),
tmpfile)
8.
verify_partial_bundle(p)
7.
plotly_build.plotly(p)
6.
plotly_build(p)
5.
htmlwidgets::saveWidget(p, f)
4.
x$elementId %||% paste("htmlwidget", createWidgetId(), sep = "-")
3.
toHTML(widget, standalone = TRUE, knitrOptions = knitrOptions)
2.
htmlwidgets::saveWidget(p, f)
1.
save_widget(partial_bundle(p), f2)

sessionInfo:

R version 4.6.1 (2026-06-24 ucrt)
Platform: x86_64-w64-mingw32/x64
Running under: Windows 10 x64 (build 19045)

Matrix products: default
  LAPACK version 3.12.1

locale:
[1] LC_COLLATE=German_Germany.utf8  LC_CTYPE=German_Germany.utf8    LC_MONETARY=German_Germany.utf8 LC_NUMERIC=C                   
[5] LC_TIME=German_Germany.utf8    

time zone: Europe/Berlin
tzcode source: internal

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] htmlwidgets_1.6.4 plotly_4.12.1     ggplot2_4.0.3     shiny_1.14.0     

loaded via a namespace (and not attached):
 [1] sass_0.4.10         generics_0.1.4      tidyr_1.3.2         digest_0.6.39       magrittr_2.0.5      evaluate_1.0.5     
 [7] grid_4.6.1          RColorBrewer_1.1-3  fastmap_1.2.0       jsonlite_2.0.0      promises_1.5.0      httr_1.4.8         
[13] purrr_1.2.2         crosstalk_1.2.2     viridisLite_0.4.3   scales_1.4.0        jquerylib_0.1.4     cli_3.6.6          
[19] rlang_1.3.0         withr_3.0.3         cachem_1.1.0        yaml_2.3.12         otel_0.2.0          tools_4.6.1        
[25] memoise_2.0.1       dplyr_1.2.1         httpuv_1.6.17       curl_8.0.0          vctrs_0.7.3         R6_2.6.1           
[31] mime_0.13           lifecycle_1.0.5     fontawesome_0.5.3   pkgconfig_2.0.3     pillar_1.11.1       bslib_0.12.0       
[37] later_1.4.8         gtable_0.3.6        data.table_1.18.6.1 glue_1.8.1          Rcpp_1.1.2          xfun_0.60          
[43] tibble_3.3.1        tidyselect_1.2.1    rstudioapi_0.19.0   knitr_1.51          farver_2.1.2        xtable_1.8-8       
[49] htmltools_0.5.9     rmarkdown_2.31      compiler_4.6.1      S7_0.2.2     

エラースタックに現れる plotly::partial_bundle と verify_partial_bundle から始め、オフラインで htmlwidgets::saveWidget を使って例を再現します。CDN バンドルに対する curl::curl_download の呼び出しを追跡し、これらのエントリポイント周辺にある既存のテストや例を調査します。報告されたオフラインワークフローが、ホスト名解決エラーなしに定義済みで検証された動作を持つことが確認できれば完了です。