Use HEAD for ref instead of master in runGitHub() (#3564)

Co-authored-by: Kathryn Doering <kathryn.doering@noaa.gov>

NEWS.md

@@ -11,6 +11,8 @@ shiny development
 
 * HTML dependencies that are sent to dynamic UI now have better type checking, and no longer require a `dep.src.href` field. (#3537)
 
+* Default for `ref` input in `runGithub()` changed from `"master"` to `"HEAD"`. (#3346)
+
 * When taking a test snapshot, the sort order of the json keys of the `input`, `output`, and `export` fields is currently sorted using the locale of the machine. This can lead to inconsistent test snapshot results. To opt-in to a consistent ordering of snapshot fields with `{shinytest}`, please set the global option `options(shiny.snapshotsortc = TRUE)`. `{shinytest2}` users do not need to set this value.  (#3515)
 
 ### Bug fixes

R/run-url.R

@@ -121,7 +121,8 @@ runGist <- function(gist, destdir = NULL, ...) {
 #' @param username GitHub username. If `repo` is of the form
 #'   `"username/repo"`, `username` will be taken from `repo`.
 #' @param ref Desired git reference. Could be a commit, tag, or branch name.
-#'   Defaults to `"master"`.
+#'   Defaults to `"HEAD"`, which means the default branch on GitHub, typically
+#'   `"main"` or `"master"`.
 #' @export
 #' @examples
 #' ## Only run this example in interactive R sessions
@@ -133,7 +134,7 @@ runGist <- function(gist, destdir = NULL, ...) {
 #'   runGitHub("shiny_example", "rstudio", subdir = "inst/shinyapp/")
 #' }
 runGitHub <- function(repo, username = getOption("github.user"),
-                      ref = "master", subdir = NULL, destdir = NULL, ...) {
+                      ref = "HEAD", subdir = NULL, destdir = NULL, ...) {
 
   if (grepl('/', repo)) {
     res <- strsplit(repo, '/')[[1]]

man/runUrl.Rd

@@ -13,7 +13,7 @@ runGist(gist, destdir = NULL, ...)
 runGitHub(
   repo,
   username = getOption("github.user"),
-  ref = "master",
+  ref = "HEAD",
   subdir = NULL,
   destdir = NULL,
   ...
@@ -47,7 +47,8 @@ all valid values.}
 \code{"username/repo"}, \code{username} will be taken from \code{repo}.}
 
 \item{ref}{Desired git reference. Could be a commit, tag, or branch name.
-Defaults to \code{"master"}.}
+Defaults to \code{"HEAD"}, which means the default branch on GitHub, typically
+\code{"main"} or \code{"master"}.}
 }
 \description{
 \code{runUrl()} downloads and launches a Shiny application that is hosted at