[Fix] nvm ls, nvm alias, nvm install: error when an LTS name is invalid

nvm.sh

@@ -196,9 +196,6 @@ nvm_install_latest_npm() {
   nvm_echo 'Attempting to upgrade to the latest working version of npm...'
   local NODE_VERSION
   NODE_VERSION="$(nvm_strip_iojs_prefix "$(nvm_ls_current)")"
-  local NPM_VERSION
-  NPM_VERSION="$(npm --version 2>/dev/null)"
-
   if [ "${NODE_VERSION}" = 'system' ]; then
     NODE_VERSION="$(node --version)"
   elif [ "${NODE_VERSION}" = 'none' ]; then
@@ -209,6 +206,8 @@ nvm_install_latest_npm() {
     nvm_err 'Unable to obtain node version.'
     return 1
   fi
+  local NPM_VERSION
+  NPM_VERSION="$(npm --version 2>/dev/null)"
   if [ -z "${NPM_VERSION}" ]; then
     nvm_err 'Unable to obtain npm version.'
     return 2
@@ -701,9 +700,7 @@ nvm_ensure_version_installed() {
       nvm_err "N/A: version \"${PREFIXED_VERSION:-$PROVIDED_VERSION}\" is not yet installed."
     fi
     nvm_err ""
-    if [ "${PROVIDED_VERSION}" = 'lts' ]; then
-      nvm_err '`lts` is not an alias - you may need to run `nvm install --lts` to install and `nvm use --lts` to use it.'
-    elif [ "${IS_VERSION_FROM_NVMRC}" != '1' ]; then
+    if [ "${IS_VERSION_FROM_NVMRC}" != '1' ]; then
         nvm_err "You need to run \`nvm install ${PROVIDED_VERSION}\` to install and use it."
       else
         nvm_err 'You need to run `nvm install` to install and use the node version specified in `.nvmrc`.'
@@ -4530,11 +4527,7 @@ nvm_supports_xz() {
   if [ "_${NVM_OS}" = '_darwin' ]; then
     local MACOS_VERSION
     MACOS_VERSION="$(sw_vers -productVersion)"
-    if tar --version | command grep -q GNU && ! command which xz >/dev/null 2>&1; then
-      # On macOS with GNU tar in use, and no xv on the path, xv-compressed
-      # tarballs aren't supported
-      return 1
-    elif nvm_version_greater "10.9.0" "${MACOS_VERSION}"; then
+    if 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

@@ -1,19 +0,0 @@
-#!/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"