nvm bash compatibility issue: Unbound variable: PATTERN

[arizvisa]

nvm debug output:

Details

$ nvm debug
nvm --version: v0.40.4
$SHELL: /bin/bash
$SHLVL: 1
whoami: 'user'
${HOME}: /home/user
${NVM_DIR}: '${HOME}/.nvm'
${PATH}: ${NVM_DIR}/versions/node/v14.17.3/bin:${HOME}/.local/bin:${HOME}/.npm/bin:${NVM_DIR}/versions/node/v14.17.3/bin:${HOME}/.config/yarn/global/node_modules/.bin:${HOME}/.yarn/bin:${HOME}/bin:${HOME}/.local/bin:/usr/local/sbin:/usr/sbin:/sbin:/usr/local/bin:/usr/bin:/bin
-bash: PREFIX: unbound variable
$PREFIX: ''
-bash: NPM_CONFIG_PREFIX: unbound variable
${NPM_CONFIG_PREFIX}: ''
-bash: NVM_NODEJS_ORG_MIRROR: unbound variable

nvm ls output:

Details

$ nvm ls
->     v14.17.3
       v16.20.2
       v20.18.0
       v20.19.5
       v22.20.0
       v24.14.1
default -> v14.17.3 *
iojs -> N/A (default)
node -> stable (-> v24.14.1 *) (default)
stable -> 24.14 (-> v24.14.1 *) (default)
unstable -> N/A (default)
lts/argon -> v4.9.1 (-> N/A)
lts/boron -> v6.17.1 (-> N/A)
lts/carbon -> v8.17.0 (-> N/A)
lts/dubnium -> v10.24.1 (-> N/A)
lts/erbium -> v12.22.12 (-> N/A)
lts/fermium -> v14.21.3 (-> N/A)
lts/gallium -> v16.20.2 *
lts/hydrogen -> v18.20.8 (-> N/A)
lts/iron -> v20.20.2 (-> N/A)
lts/jod -> v22.22.2 (-> N/A)
lts/krypton -> v24.14.1 *
lts/* -> lts/krypton (-> v24.14.1 *)

How did you install nvm?

install script

What steps did you perform?

$ nvm ls-remote

What happened?

Standard unbound variable issue.

What did you expect to happen?

Non-failure.

Is there anything in any of your profile files that modifies the PATH?

Yes, but PATH is irrelevant with regards to this issue.

Comments

There doesn't appear to be a section in this template for describing how to fix the issue, but anyways...

The lines of code that follow are from the tag v0.40.4 in the repository.

This loop inside the case for "ls-remote" will not be executed if there are no parameters specified.

nvm/nvm.sh

Lines 4187 to 4220 in 62387b8

	while [ $# -gt 0 ]; do
	case "${1-}" in
	--) ;;
	--lts)
	NVM_LTS='*'
	;;
	--lts=*)
	NVM_LTS="${1##--lts=}"
	;;
	--no-colors) NVM_NO_COLORS="${1}" ;;
	--*)
	nvm_err "Unsupported option \"${1}\"."
	return 55
	;;
	*)
	if [ -z "${PATTERN-}" ]; then
	PATTERN="${1-}"
	if [ -z "${NVM_LTS-}" ]; then
	case "${PATTERN}" in
	'lts/*')
	NVM_LTS='*'
	PATTERN=''
	;;
	lts/*)
	NVM_LTS="${PATTERN##lts/}"
	PATTERN=''
	;;
	esac
	fi
	fi
	;;
	esac
	shift
	done

Then at line 4224, the "PATTERN" variable is used without having a default value. Easy fix is to replace "${PATTERN}" with "${PATTERN:-}" similar to how it's used in multiple places throughout the library.

nvm/nvm.sh

Lines 4222 to 4229 in 62387b8

	local NVM_OUTPUT
	local EXIT_CODE
	NVM_OUTPUT="$(NVM_LTS="${NVM_LTS-}" nvm_remote_versions "${PATTERN}" &&:)"
	EXIT_CODE=$?
	if [ -n "${NVM_OUTPUT}" ]; then
	NVM_NO_COLORS="${NVM_NO_COLORS-}" nvm_print_versions "${NVM_OUTPUT}"
	return $EXIT_CODE
	fi

While running nvm debug for this issue, there were some more undefined variables. Since this is for debugging, maybe it's preferred to output an error message on a different line in order to distinguish whether an environment variable is undefined without using a placeholder value such as "<MISSING>" or something... but, that's up to the maintainer.

The lines of code in the following snippet contain the code relevant to nvm debug. Lines 3258 contains the reference to "PREFIX", with the following line 3259 referencing "NPM_CONFIG_PREFIX". Then at line 3260 is the reference to "NVM_NODEJS_ORG_MIRROR".

nvm/nvm.sh

Lines 3253 to 3264 in 62387b8

	nvm_err "\$SHLVL: ${SHLVL-}"
	nvm_err "whoami: '$(whoami)'"
	nvm_err "\${HOME}: ${HOME}"
	nvm_err "\${NVM_DIR}: '$(nvm_sanitize_path "${NVM_DIR}")'"
	nvm_err "\${PATH}: $(nvm_sanitize_path "${PATH}")"
	nvm_err "\$PREFIX: '$(nvm_sanitize_path "${PREFIX}")'"
	nvm_err "\${NPM_CONFIG_PREFIX}: '$(nvm_sanitize_path "${NPM_CONFIG_PREFIX}")'"
	nvm_err "\$NVM_NODEJS_ORG_MIRROR: '${NVM_NODEJS_ORG_MIRROR}'"
	nvm_err "\$NVM_IOJS_ORG_MIRROR: '${NVM_IOJS_ORG_MIRROR}'"
	nvm_err "shell version: '$(${SHELL} --version | command head -n 1)'"
	nvm_err "uname -a: '$(command uname -a | command awk '{$2=""; print}' | command xargs)'"
	nvm_err "checksum binary: '$(nvm_get_checksum_binary 2>/dev/null)'"