[patch] give a more helpful message when lts alias is mistakenly used

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
- nvm_err "You need to run \`nvm install ${PROVIDED_VERSION}\` to install and use it."
- else
- nvm_err 'You need to run `nvm install` to install and use the node version specified in `.nvmrc`.'
+ if [ "${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
+ 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

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"