Merge 5f7d419458beeecc1898a0181c318cffe2601dc8 into 4beab63631764fc381a0e56273faf8d43b8f9509

Fixes #3402

nvm.sh

@@ -503,9 +503,9 @@ $(nvm_wrap_with_color_code 'y' "${warn_text}")"
 }
 
 nvm_process_nvmrc() {
-  local NVMRC_PATH="$1"
+  local NVMRC_PATH
+  NVMRC_PATH="$1"
   local lines
-  local unpaired_line
 
   lines=$(command sed 's/#.*//' "$NVMRC_PATH" | command sed 's/^[[:space:]]*//;s/[[:space:]]*$//' | nvm_grep -v '^$')
 
@@ -515,8 +515,12 @@ nvm_process_nvmrc() {
   fi
 
   # Initialize key-value storage
-  local keys=''
+  local keys
-  local values=''
+  keys=''
+  local values
+  values=''
+  local unpaired_line
+  unpaired_line=''
 
   while IFS= read -r line; do
     if [ -z "${line}" ]; then
@@ -4488,7 +4492,11 @@ nvm_supports_xz() {
   if [ "_${NVM_OS}" = '_darwin' ]; then
     local MACOS_VERSION
     MACOS_VERSION="$(sw_vers -productVersion)"
-    if nvm_version_greater "10.9.0" "${MACOS_VERSION}"; then
+    if tar --version | command grep -q GNU && ! command which xz >/dev/null 2>&1; then
+      # On macOS with GNU tar in use, and no xv on the path, xv-compressed
+      # tarballs aren't supported
+      return 1
+    elif nvm_version_greater "10.9.0" "${MACOS_VERSION}"; then
       # macOS 10.8 and earlier doesn't support extracting xz-compressed tarballs with tar
       return 1
     fi