add gh_wrapper to fallback for 401 calls

This allows users with bad credentials (they expired or were
misconfigured in the first place) to install pandoc using the limited
API without credentials.

This will fix cderv#30

Author: zkamvar

NEWS.md

@@ -1,5 +1,8 @@
 # pandoc (development version)
 
+-   pandoc installation will no longer immediately fail for users with bad 
+    GitHub credentials
+
 # pandoc 0.2.0
 
 -   input and output path containing short path version using `~` now works (thanks, @olivroy, #31)

R/pandoc-install.R

@@ -149,14 +149,14 @@ pandoc_install_nightly <- function(n_last = 1L) {
   version <- "nightly"
   install_dir <- pandoc_home(version)
   rlang::inform(c(i = "Retrieving last available nightly informations..."))
-  runs <- gh::gh("/repos/jgm/pandoc/actions/workflows/nightly.yml/runs",
+  runs <- gh_wrapper("/repos/jgm/pandoc/actions/workflows/nightly.yml/runs",
     .limit = max(15L, n_last + 5)
   )
   runs <- keep(runs$workflow_runs, ~ .x$conclusion == "success")
   ind <- min(length(runs), n_last)
   artifacts_url <- runs[[ind]][["artifacts_url"]]
   head_sha <- runs[[ind]][["head_sha"]]
-  artifacts <- gh::gh(artifacts_url)
+  artifacts <- gh_wrapper(artifacts_url)
   artifact_url <- keep(artifacts$artifacts, ~ .x$name == bundle_name)[[1]][["archive_download_url"]]
   if (fs::dir_exists(install_dir)) {
     current_version <- pandoc_nightly_version()
@@ -171,7 +171,7 @@ pandoc_install_nightly <- function(n_last = 1L) {
   bundle_name <- fs::path_ext_set(head_sha, "zip")
   rlang::inform(c(i = "Installing last available nightly..."))
   tmp_file <- with_download_cache("nightly", bundle_name, {
-    gh::gh(artifact_url, .destfile = bundle_name)
+    gh_wrapper(artifact_url, .destfile = bundle_name)
   })
 
   utils::unzip(tmp_file, exdir = install_dir, junkpaths = TRUE)
@@ -293,7 +293,7 @@ pandoc_releases <- function() {
 fetch_gh_releases <- function(limit = Inf) {
   gh_required()
   rlang::inform(c(i = "Fetching Pandoc releases info from github..."))
-  gh::gh(
+  gh_wrapper(
     "GET /repos/:owner/:repo/releases",
     owner = "jgm",
     repo = "pandoc",
@@ -337,6 +337,23 @@ pandoc_os <- function() {
   )
 }
 
+# fallback for bad token errors. See 
+# https://github.com/cderv/pandoc/issues/30#issuecomment-1691712036
+# for details
+gh_wrapper <- function(...) {
+  tryCatch(gh::gh(...),
+    http_error_401 = function(e) {
+      rlang::inform(c(
+        "!" = "Bad GitHub credentials found", 
+        i = "Attempting to install without credentials..."))
+      # if we get a 401 error, the user has a bad token and we should try with
+      # an empty token
+      e$call$.token <- ""
+      eval(e$call)
+    }
+  )
+}
+
 # nocov start
 gh_required <- function() {
   rlang::check_installed(