From 48a93e4fc0f7bc0f7c02c42bbac2a371873d4021 Mon Sep 17 00:00:00 2001
From: Rok Cesnovar <rok.cesnovar@fri.uni-lj.si>
Date: Mon, 19 Jul 2021 11:12:16 +0200
Subject: [PATCH 1/2] check for arch to download appropriate tarball

---
 R/install.R | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/R/install.R b/R/install.R
index eae3600df..2bc82a084 100644
--- a/R/install.R
+++ b/R/install.R
@@ -99,8 +99,9 @@ install_cmdstan <- function(dir = NULL,
       warning("version and release_url shouldn't both be specified!",
               "\nrelease_url will be ignored.", call. = FALSE)
     }
+
     release_url <- paste0("https://github.com/stan-dev/cmdstan/releases/download/v",
-                          version, "/cmdstan-", version, ".tar.gz")
+                          version, "/cmdstan-", version, cmdstan_arch_suffix(version), ".tar.gz")
   }
   if (!is.null(release_url)) {
     if (!endsWith(release_url, ".tar.gz")) {
@@ -118,7 +119,7 @@ install_cmdstan <- function(dir = NULL,
   } else {
     ver <- latest_released_version()
     message("* Latest CmdStan release is v", ver)
-    cmdstan_ver <- paste0("cmdstan-", ver)
+    cmdstan_ver <- paste0("cmdstan-", ver, cmdstan_arch_suffix(ver))
     tar_gz_file <- paste0(cmdstan_ver, ".tar.gz")
     dir_cmdstan <- file.path(dir, cmdstan_ver)
     message("* Installing CmdStan v", ver, " in ", dir_cmdstan)
@@ -300,9 +301,10 @@ github_auth_token <- function() {
 
 # construct url for download from cmdstan version number
 github_download_url <- function(version_number) {
+
   base_url <- "https://github.com/stan-dev/cmdstan/releases/download/"
   paste0(base_url, "v", version_number,
-         "/cmdstan-", version_number, ".tar.gz")
+         "/cmdstan-", version_number, cmdstan_arch_suffix(), ".tar.gz")
 }
 
 # get version number of latest release
@@ -614,3 +616,15 @@ check_unix_cpp_compiler <- function() {
     }
   }
 }
+
+cmdstan_arch_suffix <- function(version = NULL) {
+  arch <- NULL
+  if (grepl("linux", R.version$os) && grepl("aarch64", R.version$arch)) {
+    arch <- "-linux-arm64"
+  }  
+  if (!is.null(version) && version < "2.26" && !is.null(arch_suffix)) {
+    # pre-CmdStan 2.26, only the x85 tarball was provided
+    arch <- NULL
+  }
+  arch
+}
\ No newline at end of file

From 849915fc5a996093c3e7cf29c637acc38cc91c46 Mon Sep 17 00:00:00 2001
From: Rok Cesnovar <rok.cesnovar@fri.uni-lj.si>
Date: Mon, 19 Jul 2021 12:38:43 +0200
Subject: [PATCH 2/2] fix bug

---
 R/install.R | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/R/install.R b/R/install.R
index 2bc82a084..da48880bd 100644
--- a/R/install.R
+++ b/R/install.R
@@ -622,7 +622,7 @@ cmdstan_arch_suffix <- function(version = NULL) {
   if (grepl("linux", R.version$os) && grepl("aarch64", R.version$arch)) {
     arch <- "-linux-arm64"
   }  
-  if (!is.null(version) && version < "2.26" && !is.null(arch_suffix)) {
+  if (!is.null(version) && version < "2.26") {
     # pre-CmdStan 2.26, only the x85 tarball was provided
     arch <- NULL
   }