Merge 5f7d419458beeecc1898a0181c318cffe2601dc8 into 5dc31ac51b08f910a2de1596b37a6a3dddd5e7b7

GNU tar doesn't support using the -J flag required to unpack
xz-compressed tarballs when xv isn't installed. Check for this
scenario and fallback to using gzip-compressed tarballs.

Fixes #3034

nvm.sh

@@ -700,10 +700,12 @@ nvm_ensure_version_installed() {
       nvm_err "N/A: version \"${PREFIXED_VERSION:-$PROVIDED_VERSION}\" is not yet installed."
     fi
     nvm_err ""
-    if [ "${IS_VERSION_FROM_NVMRC}" != '1' ]; then
+    if [ "${PROVIDED_VERSION}" = 'lts' ]; then
-        nvm_err "You need to run \`nvm install ${PROVIDED_VERSION}\` to install and use it."
+      nvm_err '`lts` is not an alias - you may need to run `nvm install --lts` to install and `nvm use --lts` to use it.'
-      else
+    elif [ "${IS_VERSION_FROM_NVMRC}" != '1' ]; then
-        nvm_err 'You need to run `nvm install` to install and use the node version specified in `.nvmrc`.'
+      nvm_err "You need to run \`nvm install ${PROVIDED_VERSION}\` to install and use it."
+    else
+      nvm_err 'You need to run `nvm install` to install and use the node version specified in `.nvmrc`.'
     fi
     return 1
   fi
@@ -4527,7 +4529,11 @@ nvm_supports_xz() {
   if [ "_${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

test/slow/nvm use/Running 'nvm use lts' shows actionable error

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+set -ex
+
+die () { echo "$@" ; exit 1; }
+
+\. ../../../nvm.sh
+
+# Deactivate any active node version
+nvm deactivate >/dev/null 2>&1 || die 'deactivate failed'
+
+# Attempt to use 'lts' without '--' and capture the error message
+ERROR_OUTPUT=$(nvm use lts 2>&1) || true
+
+EXPECTED_ERROR='`lts` is not an alias - you may need to run `nvm install --lts` to install and `nvm use --lts` to use it.'
+
+# Check if the error message matches the expected output
+echo "$ERROR_OUTPUT" | grep -q "$EXPECTED_ERROR" \
+  || die "Expected error message not found. Got: $ERROR_OUTPUT"