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     

从错误堆栈中出现的 plotly::partial_bundle 和 verify_partial_bundle 开始，并在离线时使用 htmlwidgets::saveWidget 重现该示例。跟踪用于下载 CDN bundle 的 curl::curl_download 调用，并检查这些入口点附近现有的测试或示例。当所报告的离线工作流在没有主机名解析错误的情况下具有已定义且经过验证的行为时，即视为完成。