[Fix] ensure --reinstall-packages-from has a version number.

Fixes #1760.

nvm.sh

@@ -2558,8 +2558,16 @@ nvm() {
         case "$1" in
           --reinstall-packages-from=*)
             PROVIDED_REINSTALL_PACKAGES_FROM="$(nvm_echo "$1" | command cut -c 27-)"
+            if [ -z "${PROVIDED_REINSTALL_PACKAGES_FROM}" ]; then
+              nvm_err 'If --reinstall-packages-from is provided, it must point to an installed version of node.'
+              return 6
+            fi
             REINSTALL_PACKAGES_FROM="$(nvm_version "$PROVIDED_REINSTALL_PACKAGES_FROM")" ||:
           ;;
+          --reinstall-packages-from)
+            nvm_err 'If --reinstall-packages-from is provided, it must point to an installed version of node using `=`.'
+            return 6
+          ;;
           --copy-packages-from=*)
             PROVIDED_REINSTALL_PACKAGES_FROM="$(nvm_echo "$1" | command cut -c 22-)"
             REINSTALL_PACKAGES_FROM="$(nvm_version "$PROVIDED_REINSTALL_PACKAGES_FROM")" ||:

test/fast/Running "nvm install" with "--reinstall-packages-from" requires a valid version

@@ -39,4 +39,18 @@ set -e
 [ $INSTALL_EXIT_CODE -eq 4 ] \
   || die ""nvm install --reinstall-packages-from" should exit with code 4 when given the same version, got $INSTALL_EXIT_CODE"
 
+set +ex # needed for stderr
+INSTALL_ERROR_MSG="$(nvm install v0.10.5 --reinstall-packages-from 2>&1)"
+set -ex
+EXPECTED_ERROR_MSG='If --reinstall-packages-from is provided, it must point to an installed version of node using `=`.'
+[ "~$INSTALL_ERROR_MSG" = "~$EXPECTED_ERROR_MSG" ] \
+  || die ""nvm install --reinstall-packages-from" should fail when given an uninstalled version: expected '$EXPECTED_ERROR_MSG', got '$INSTALL_ERROR_MSG'"
+
+set +ex # needed for stderr
+INSTALL_ERROR_MSG="$(nvm install v0.10.5 --reinstall-packages-from= 2>&1)"
+set -ex
+EXPECTED_ERROR_MSG="If --reinstall-packages-from is provided, it must point to an installed version of node."
+[ "~$INSTALL_ERROR_MSG" = "~$EXPECTED_ERROR_MSG" ] \
+  || die ""nvm install --reinstall-packages-from" should fail when given an uninstalled version: expected '$EXPECTED_ERROR_MSG', got '$INSTALL_ERROR_MSG'"
+
 cleanup